Progress in Dentistry

EDITORIAL

Progress in Dentistry Remarkable paradox. Remarkable challenge.

DENTAL TECHNOLOGY continues to evolve at an unprecedented rate. A cursory perusal of the content of local, state, national and international continuing education programs attests to our perception that there has been a notable surge in relevant scientific advancements in dentistry over the past few years. At the same time, the dental clinician’s strong interest in these advances is undeniable. Our ability to replace teeth (implants) as well as our capability, in many instances, to improve the specific biologic environment where these implants will, it is hoped, thrive and remain (site development) could not have been imagined 25 years ago. The link between oral health and systemic disease states has become more clearly defined. Similarly, stem cell research utilizing undifferentiated cells from human tooth pulp tissue holds the promise of dramatically improving future dental and medical care. Additionally, we have identified the etiology of dental caries and its transmissibility mechanisms. And we have developed specific protocols that have shown to be incontrovertibly effective in preventing this disease. The problem of limited access to oral health care has received considerable attention in the past few years. There is growing concern that our modern dental technology and exquisite academic and clinical training programs are not benefiting large segments of the public. There appear to be reversals in oral health status nationally and abroad. Identifying the constellation of complex factors that might be contributing to limiting access will be a fundamental step in removing current obstacles to oral health care for all. Some 4 NYSDJ • MARCH 2008

of these areas might include creating incentives for recent dental school graduates to relocate either temporarily or permanently to underserved areas. Incentives should include some form of “loan forgiveness” or monetary consideration in light of the tremendous personal debt that dental school graduates typically have. Naturally, such an incentive must also include removing any existing barriers to the freedom of professional movement within the U.S. Who will be leading this effort to bring the benefits of modern dentistry to a larger segment of our population? It will be the tripartite dental organization, led by the American Dental Association. It will be the ADA who will visibly and genuinely remain proactive in oral health care access issues as a major stakeholder and who will not remain on the side lines and, perhaps, on the “coat tails” of other heath professions. The ADA will be challenged to find creative paths to consequentially partner with academic and research institutions, the dental manufacturing industry, government, the public and individual dentists, all in an effort to resolve the pressing problem of oral health care access, while, at the same time, protecting the sanctity of the dentist/patient relationship. These are exciting and challenging times for the dental profession and individual dentists. Only through our powerful collective voice, the American Dental Association, can we hope to achieve our enlightened goals. D.D.S. M.Sd

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OFFICERS Stephen B. Gold, President Steven Gounardes, Immediate Past President 8 Medical Drive, Port Jefferson Station, NY 11776 351 87th St., Brooklyn, NY 11209 Michael R. Breault, President Elect 1368 Union St., Schenectady, NY 12308

Roy E. Lasky, Executive Director 20 Corporate Woods Boulevard, Albany, NY 12211

Robert Doherty, Vice President 280 Mamaroneck Ave., White Plains, NY 10605 Richard Andolina, Secretary-Treasurer 74 Main St., Hornell, NY 14843

William R. Calnon, ADA Trustee 3220 Chili Ave., Rochester, NY 14624

BOARD OF GOVERNORS NY County-Lawrence Bailey 215 W. 125th St., New York, NY 10027 NY County-Matthew J. Neary 501 Madison Ave., Fl. 22, New York, NY 10022 NY County- Robert B. Raiber 630 Fifth Ave., #1869, New York, NY 10111 2-Craig S. Ratner 7030 Hylan Blvd., Staten Island, NY 10307 2-James J. Sconzo 1666 Marine Parkway, Brooklyn, NY 11234 3-Lawrence J. Busino 2 Executive Park Dr., Albany, NY 12203 3-John P. Essepian 180 Old Loudon Rd., Latham,NY 12110 4-Mark A. Bauman 157 Lake Ave., Saratoga Springs, NY 12866 4-James E. Galati Parkwood Plaza, 1758 Rte. 9, Clifton Park, NY 12065 5-William H. Karp 472 S. Salina St., #222, Syracuse, NY13202 5-John J. Liang 2813 Genessee St., Utica, NY 13501 6-Robert G. Baker Jr. 803-805 Cascadilla St., Ithaca, NY 14850 6-Scott Farrell 39 Leroy St., Binghamton, NY 13905 7-Robert J. Buhite II 1295 Portland Ave., Rochester, NY 14621 7-Andrew G. Vorrasi 2005-A Lyell Ave., Rochester, NY 14606

8- Jeffrey A. Baumler 2145 Lancelot Dr., Niagara Falls, NY 14304 8- Kevin J. Hanley 959 Kenmore Ave., Buffalo, NY 14223-3160 9-Edward Feinberg 14 Harwood Ct., Ste. 322, Scarsdale, NY 10583 9-Malcolm S. Graham 170 Maple Ave., White Plains, NY 10601 9- Neil R. Riesner 111 Brook St., 3rd Floor, Scarsdale, NY 10583-5149 N- Peter M. Blauzvern 366 N. Broadway, Jericho, NY 11753-2032 N-David J. Miller 467 Newbridge Rd., E. Meadow, NY 11554 N-Frank J. Palmaccio 2 Bayard Drive, Dix Hills, NY 11746 Q-Chad P. Gehani 35-49 82nd St., Jackson Heights, NY 11372 Q-Robert L. Shpuntoff 28 Beverly Rd., Great Neck, NY 11021 S-Paul R. Leary 80 Maple Ave., #206, Smithtown, NY 11787 S-Steven I. Snyder Suffolk Oral Surgery, 264 Union Ave., Holbrook, NY 11741 B-Stephen B. Harrison 1668 Williamsbridge Rd., Bronx, NY 10461 B-Richard P. Herman 20 Squadron Blvd., New City, NY 10956

Address Correction Dr. Howell Archard was kind enough to forward me a copy of the article “Congenital Diseases and a New York State Regulation” that appeared in the June/July NYSDJ, as well as his letter in response to the article, which was printed in the November Journal. In his letter, Dr. Archard says X-Linked Hypophosphatemic Rickets (sometimes still known as Vitamin D Resistant Rickets) should be included in the list of congenital diseases that affect the teeth as well as the bones. Dr. Archard mentioned our organization, but there was an error in the Web site address. Please let people know that the correct Web address for The XLH Network is www.xlhnetwork.org. We also have a listserv open to people affected by the condition, as well as to physicians and researchers interested in the condition. The listserve is F—HYPDRR. Somehow, the two addresses became intertwined. We greatly appreciate your help in getting the information out that at least in New York State, medical insurance is responsible for dental treatment that becomes necessary for congenital diseases such as XLH. Joan Reed, President XLH Network 4562 Stoneledge Lane, Manlius, NY 13104

You Are Invited

COUNCIL CHAIRPERSONS Annual Meetings Alan L. Mazer P.O. Box 985, 140 Terryville Rd. Pt. Jefferson Station, NY 11776 Awards William R. Calnon 3220 Chili Ave., Rochester, NY 14624 Chemical Dependency Robert J. Herzog 16 Parker Ave., Buffalo, NY 14214 Dental Benefit Programs Ian M. Lerner One Hanson Pl., #2900 Brooklyn, NY 11243-2907 Dental Health Planning/ Hospital Dentistry Robert A. Seminara 281 Benedict Rd., Staten Island, NY 10304 Dental Practice Steven L. Essig 33 Main St., Ravena, NY 12143 Dental Education & Licensure Madeline S. Ginzburg 2600 Netherland Ave., #117 Riverdale, NY 10463 Ethics Kevin A. Henner 163 Half Hollow Rd., #1, Deer Park, NY 11729

Letters

Governmental Affairs Alan L. Mazer P.O. Box 985, 140 Terryville Rd. Pt. Jefferson Station, NY 11776 Insurance Roland C. Emmanuele 4 Hinchcliffe Dr. Newburgh, NY 12550 Membership & Communications Lidia Epel 165 N. Village Ave. #102 Rockville Center, NY 11570 New Dentist David C. Bray 18 Leroy St., Binghamton, NY 13905 Nominations Steven Gounardes 351 87th St., Brooklyn, NY 11209 Peer Review & Quality Assurance Steven Damelio 1794 Penfield Rd. Penfield, NY 14526 Relief Anthony V. Maresca 207 Hallock Rd. Stony Brook, NY 11790 NYSDJ •

OFFICE Suite 602 20 Corporate Woods Blvd. Albany, NY 12211 (518) 465-0044 (800) 255-2100 Roy E. Lasky Executive Director Carla Hogan General Counsel Beth M. Wanek Associate Executive Director Michael J. Herrmann Assistant Executive Director Finance-Administration Judith L. Shub Assistant Executive Director Health Affairs Sandra DiNoto Director Public Relations Mary Grates Stoll Managing Editor

NYSDA PRESIDENT’S DINNER DANCE HONORING PRESIDENT STEPHEN B. GOLD & THE OFFICERS OF THE ASSOCIATION FOR 2008 SATURDAY, JUNE 7, 2008 Cocktails & Hors d’Oeuvres 7:30 - 8:30 p.m. DINNER 8:30 P.M. Lombardi’s on the Sound at the Port Jefferson Country Club at Harbor Hills 44 Fairway Drive Port Jefferson, New York ATTIRE: BLACK TIE $95 PER PERSON RSVP: Beth Wanek, NYSDA

MARCH 2008 5 NYSDJ • MARCH 2008 5

NYSDA Chooses Seaside Resort as Setting FOR SEMI-ANNUAL MEETING PRIOR TO 1836, Port Jefferson was known as Drowned Meadow, because of the flooding that took place at every high tide in what is today the village’s business district. Town fathers realized that an allusion to death by water was probably not desirable for a community of shipbuilders, and, so, the name of the settlement was changed to Port Jefferson. The new name came easy. It was, after all, a harbor village, and President Thomas Jefferson was reputed to be the major source of funding for a project to prevent the flooding. When NYSDA gathers in Port Jefferson, on the north shore of Long Island, in June for the Semi-Annual Meeting of its Board of Governors, they’ll find few remnants from the Drowned Meadow days, but plenty of reminders, nonetheless, that this is a village with close ties to the sea and a storied maritime past. This year’s meeting will take place June 5-8 at the Port Jefferson Village Center and nearby Danfords on the Sound. The meeting is being hosted by the Suffolk County Dental Society, whose past president,Stephen B.Gold,will be formally installed as NYSDA President at a dinner dance on Saturday, June 7. Standing up with Dr. Gold will be his fellow officers: President Elect Michael R. Breault; Vice President Robert J. Doherty; Secretary-Treasurer Richard F.Andolina; and Immediate Past President Steven Gounardes. The small town of Port Jefferson, for all its colorful history, is a deceptively cosmopolitan community. Located just 56 miles east of New York City, it boasts several unique restaurants and shops and a growing tourism industry, developed around the town’s many natural attractions, museums and historic sites, and special events. 10 NYSDJ • MARCH 2008

Danfords, which opened in 1986 as an inn, conference center marina, restaurant and catering facility, is itself a tourist attraction. The site is located along the nationally recognized North Shore Heritage Trail and was previously occupied by a painter’s studio, blacksmith shop, boxing emporium, social club and ice cream parlor. The Board of Governors will hold its opening session from 3 to 6 p.m., Thursday, June 5. It will continue deliberations on Saturday during an all-day session that will begin at 9 a.m. The annual luncheon of the New York State chapter of the Pierre Fauchard Academy is also scheduled for Saturday. Arrangements for the meeting are being coordinated by this year’s Annual Meeting Chair Alan L. Mazer. Requests for information should be made to NYSDA Associate Executive Director Beth Wanek at (800) 255-2100 or [email protected].

Getting to Know Port Jefferson Weekend on Long Island Filled with Local Attractions CHAMPAGNE, CHOCOLATE & JEWELRY (Thursday June 5): Ecolin Jewelers, a family-owned jewelry store located across the street from Danfords, is opening its doors especially for NYSDA so that meeting-goers can browse their collection of fine jewelry. While there, enjoy a glass of champagne and a 10% discount off any purchases made between 4 and 6 p.m. Ecolin represents many renowned designers, among them, Lagos, Carrera y Carrera and Tacori.Your Host: Ruth Gold. There is no fee for this event.

Modern-day Port Jefferson continues to build on its maritime past.

LOBSTER BAKE (Thursday June 5): The first social gathering of the meeting takes place at the Three Village Inn. A short ride from the site of the meeting, the Three Village Inn is a charming country get-away, the crown jewel of historic Stony Brook and site of one of Long Island’s great restaurants. The night begins with cocktails and hors d’oeuvres at 7 p.m., followed by an authentic Long Island lobster bake. Price includes transportation from Danfords, open bar and music. Fee: $65 per person. GOLF TOURNAMENT (Friday June 6): Suffolk County Dental Society has invited NYSDA guests to play in its annual tournament at Great Rock Golf Club in Wading River. Great Rock is the newest semi-private club on Long Island. Golfers of all abilities will enjoy this par-71 course, laid out on 136 acres of mature woodlands, overlooking sprawling vistas. This is a shot-gun, scramble tournament. It will begin at 8 a.m. Transportation will be provided for hotel guests and will depart at 6:30 a.m. Entry fee includes greens fees, cart, Continental breakfast, lunch and prizes. Tournament Chairman: Dr. Anthony Maresca. Fee: $195 per person. LONG ISLAND SOUND FISHING (Friday June 6): Spend the morning with Capt. Desmond O’Sullivan and his crew aboard the “Celtic Quest,” a pristine and comfortable 60-foot party fishing boat. Set sail at 7 a.m. from the town dock, just a short walk from Danfords. You will return at approximately 1:30 p.m. If you’re already an accomplished fisherperson, this is a chance to sharpen your skills. If you’re more accustomed to getting your fish from a market, you’re still welcome to join the party and learn techniques, tactics and what gear to use to catch the big fish. Who knows? You may get lucky. No prior fishing or boating experience is necessary. Bring a jacket or sweatshirt and a pair of old sneakers. Price includes rods, bait and tackle, gratuity, boxed lunch and beverages. Your Host: Dr. Alan Mazer. Fee: $60 per person. WINERY TOUR (Friday June 6): Take a scenic ride to the North Fork of Long Island to visit two of the Island’s premiere wineries.Your first stop will be Paumanok Vineyards, a family-owned, 77-acre estate. Its winery is housed in a renovated turn-of-the-century barn, surrounded by an inviting deck that overlooks the vineyards. Lunch follows at the Jamesport Manor Inn, a beautiful reproduction of a 19thcentury Victorian house, which specializes in new American cuisine, with Mediterranean and Asian accents. Last stop is a wine tasting at Martha Clara Vineyards, owned and operated by the Entenmann family, also known for the baked goods it produces. This is a firstclass winery, noted for the knowledge, skill and experience that go into the wine it produces. The bus will depart Danfords at 9:30 a.m. and will return at approximately 3:15 p.m.Your Hosts: Dr.Kerry Lane and Dr. Thomas Bonomo. Fee: $50 per person. COCKTAIL & DESSERT RECEPTION (Friday June 6): NYSDA will not be hosting a dinner function on Friday evening. This will give you a chance to enjoy any of the excellent restaurants located in

Port Jefferson. To get you started on your evening, Suffolk County Dental Society is sponsoring a cocktail reception from 6 to 7 p.m. at Danfords. And save room for dessert. When you get back from dinner, you are invited to a dessert reception at Danfords. Coffee, sweets and cordials will be served from 9:30 to 11 p.m., courtesy of MLMIC, which is underwriting the cost of this event. There is no fee for this event. STONY BROOK MUSEUM TOUR/SHOPPING (Saturday, June 7): The Long Island Museum of American Art, History and Carriages is a showcase for artifacts depicting everyday life in early America, works of art and nearly 200 historic carriages. It’s Long Island’s largest privately supported museum and is accredited by the American Association of Museums for excellence in exhibitions and programs. The museum’s permanent collection numbers over 40,000 items, dating from the late 18th century to the present.Your outing will continue with lunch at Pasta Pasta. If after lunch, you’re still not ready to return to the hotel, you will have time to tour the quaint village of Port Jefferson, stopping at its many and diverse shops and boutiques. Visitor’s guides and maps will be provided. It’s just a short walk from the village of Port Jefferson to Danfords. Your Hosts: Lois Mazer, Dr. Robert & Doreen Benton. Suffolk Oral Surgery Associates, LLP (Drs. Steven Snyder, Guenter Jonke, John Guariglia, Sachin Jamdar and Christopher First) are underwriting the cost of this event. Fee: $35 per person. NATURE TRAIL HIKING/PONTOON BOATING (Saturday, June 7): The Ward Melville Heritage Organization, a not-for-profit corporation was founded to preserve and protect historical and sensitive environmental properties in Stony Brook. On this trip, you will spend approximately one hour hiking the trails of the preserve, then board the 35-passenger vessel, the “Discovery,” for a one and one-half hour tour of the organization’s 88-acre wetlands. A naturalist from the Stony Brook University Marine Sciences Center will be on board to describe the wildlife and flora. Bus departs Danfords at 12:45 p.m. and will return at approximately 5:15 p.m. Wear sneakers or hiking shoes. Your Host: Dr. John Primavera. Fee: $23/Adults; $18/Seniors; $10/Children under 6. PRESIDENT’S DINNER DANCE (Saturday June 7): Join your friends and colleagues at NYSDA’s Annual Dinner Dance as they honor the Association’s 2008 President, Stephen B. Gold, his wife, Ruth, and the other officers of NYSDA. This gala event will be held at Lombardi’s on the Sound at the Port Jefferson Country Club. The evening begins with cocktails and hors d’oeuvres at 7:30 p.m. Dinner and dancing will follow. Black tie attire. Transportation will be provided for hotel guests. Fee: $95 per person. FAREWELL BREAKFAST (Sunday, June 8): Dr. Barry Rifkin and the office of the dean of Stony Brook University have invited everyone to join them for breakfast at Danfords prior to their departure. A hearty buffet will be available from 7 to 10 a.m. NYSDJ • MARCH 2008 11

NEW YORK STATE DENTAL ASSOCIATION 2008 SEMI-ANNUAL MEETING Port Jefferson Village Center Dansfords on the Sound Port Jefferson, New York June 5 - 8, 2008

THURSDAY, JUNE 5 10 am - 5 pm 12:30 - 3 pm 3 - 6 PM 4 - 6 PM 7 pm

Registration — Hotel Lobby (Danfords) NYSDA Support Services — Boardroom 4 (Danfords) Board of Governors — Port Jefferson Village Center Champagne, Chocolate, Jewelry Reception Ecolin Jeweler’s Lobster Bake — Three Village Inn Bus Transportation Provided

FRIDAY, JUNE 6 7 am

8 am 9 am - 3 pm 9:30 am 6 - 7 pm 9:30 - 11pm

Fishing Trip depart from Town Dock return approx 1:30 pm boxed lunch/beverages Annual Golf Tournament w/Suffolk County Dental Society — Great Rock Golf Course in Wading River Registration — Hotel Lobby (Danfords) Winery Tour & Lunch Cocktail Reception — Brookhaven Ballroom (Danfords) Dessert Reception — Brookhaven Ballroom (Danfords)

SATURDAY, JUNE 7 8 am - 3 pm 9 am - 5 pm 9:30 am

12:45 pm Noon - 1:30 pm 7:30 pm - 12:30 pm

Registration — Hotel Lobby (Danfords) Board of Governors — Port Jefferson Village Center Museum Tour Stony Brook Museum Lunch Shopping in Port Jefferson Departure for Nature Trail Hiking/Pontoon Boating Returning at 5:15 p.m. Pierre Fauchard Academy Luncheon — Brookhaven Ballroom (Danfords) President’s Dinner Dance — Lombardi’s on the Sound at Port Jefferson Country Club Cocktail Reception 7:30 - 8:30 pm Dinner/Dancing 8:30 pm - Midnight Transportation Provided Black Tie

SUNDAY, JUNE 8 8 - 10 am

12 NYSDJ • MARCH 2008

Farewell Breakfast — Danfords Inn Check-in time — 4 p.m. Check-out time — 11 a.m.

EVENT REGISTRATION Please register the following individual(s) for the meeting. Please print names as they are to appear on badges. Badges may be picked up at the NYSDA Registration Desk.

# OF TICKETS

TOTAL COST

THURSDAY JUNE 5

CHAMPAGNE RECEPTION No Charge LOBSTER BAKE $65 Per Person FRIDAY JUNE 6

GOLF (complete separate registration) $195 Per Person FISHING $60 Per Person WINERY TOUR $50 Per Person COCKTAIL RECEPTION No Charge DESSERT RECEPTION No Charge SATURDAY JUNE 7

STONY BROOK MUSEUM/SHOPPING $35 Per Person NATURE TRAIL HIKE/PONTOON BOATING $23 Adults / $18 Seniors / $10 Child Under 6 PRESIDENT’S DINNER DANCE $95 Per Person SUNDAY JUNE 8

FAREWELL BREAKFAST No Charge TOTAL

$

NYSDJ • MARCH 2008 13

Craig Ratner, third from left, receives congratulations on winning Tillis Award for excellence in dental writing. Well-wishers are, from left, NYSDJ Editor Elliott Moskowitz; Deborah Pasquale, NYSDA Council Membership & Communications; Steven Gounardes, 2007 NYSDA President.

Council Selects Craig Ratner to Receive Tillis Award ROBERT KELSCH GETS HONORABLE MENTION CRAIG S. RATNER, president of the Second District Dental Society, is winner of the 2007 Bernard P. Tillis Award for excellence in dental writing. Dr. Ratner was selected to receive the award, presented by the NYSDA Council on Membership and Communications, for his editorial “A Troubling Trip to the Local Elementary School” in the June/July 2007 SDDS Bulletin. Dr. Ratner is co-editor of the Bulletin. He received an inscribed plaque. The Council on Membership and Communications also selected Nassau County Editor Robert D. Kelsch, D.M.D., for an Honorable Mention citation for his untitled editorial about globalization in the November/December 2006 Bulletin of NCDS. Dr.

Kelsch is a 1992 graduate of the University of Connecticut School of Dental Medicine. He is an oral pathologist in Rockville Center. The Tillis Award was established in 1996 to honor the memory of the longtime New York State Dental Journal editor. It recognizes members of the Dental Association who, through their writing in The NYSDJ or in any component publication, promotes a positive image of organized dentistry. Dr. Ratner, a 1992 graduate of New Jersey Dental School, is a general practitioner on Staten Island. He represents the Second District on the NYSDA Board of Governors and is an alternate delegate to the ADA. He is past president of the Richmond County Dental Society. His winning editorial is reproduced here.

A TROUBLING TRIP TO THE LOCAL ELEMENTARY SCHOOL Editorial Craig S. Ratner, D.M.D.

A FUNNY THING happened last week. While at my home in New Jersey, I was called by the school nurse to come to my daughter’s school. My daughter needed allergy drops placed in her eyes. This is not the funny part. As I arrived in the nurse’s office, I noticed another little girl playing with a loose tooth. She was unsuccessfully attempting to free it from its gingival jail. She was to the point of tears when I heard the nurse say, “I’m sorry. I can’t help you. Only a dentist can pull a tooth from your mouth.” Noting the irony, I replied, “I’m a dentist. Can I help?” Acknowledging my arrival, the nurse did indeed propose to the young girl that I could help. The young girl was a little reluctant, but the discomfort she was having convinced her to let me help. I reached for the nearest tissue and proceeded to do what most parents do for their children all the time. I painlessly plucked the baby tooth from her mouth with nary a yelp or a tear. The nurse provided a piece of gauze for my “patient” to bite on and sent her back to class. I was a hero, right? On the way home, I was struck by a strange thought. I considered that I had just done something wrong. I had actually treated a minor without her parents’ consent. Not only that, but I did it in a state in which I wasn’t licensed. Now, I knew that I would probably never be arrested for committing these two class B felonies. However, there was 14 NYSDJ • MARCH 2008

a small part of me that actually worried that this little girl’s parents might be some lawsuit-happy Americans who saw this as an opportunity to sue me even though I was doing something I thought was innocent and good. Of course, I kept telling myself that I was overreacting. I was upset nonetheless. I wasn’t upset over a potential lawsuit. Rather,I was upset that the thought even crossed my mind.I was upset that I live in a society where this was even a consideration. I was upset that I let myself get caught in the trap of paranoia.Then,I thought of all that NYSDA has done over the past five years to fight off the advances of the New York State Trial Lawyers Association. It is one of the most important yet unnoticed benefits of our membership,one that we often overlook. We have spent untold time and dollars fighting off the NYSTLA’s legislative efforts to eliminate the statute of limitations and to create new categories of wrongful death and non-economic damages. It is an ongoing battle. How do we convince legislators who are themselves lawyers to ignore the influences of fellow lawyers? So far we have, but we need to continue the fight.We need to maintain our presence in Albany with numbers and dollars. If our numbers fail to show that we significantly represent our profession, or if our lobbying efforts fail because we lack monetary strength, we are in serious trouble. This is important. I for one don’t want to have to worry about helping out another young girl with a loose tooth.

PERSPECTIVES

Dentistry and Dental Technology What went wrong with what was once a beautiful relationship? Can that old feeling be restored?

Burney M. Croll, D.D.S. IN THE PAST 39 YEARS, since I graduated from the University at Buffalo School of Dental Medicine, there have been many changes in dental education, especially in its relationship to dental technology. There have been changes in dental technology as well, including the number of dental technologists and their education and the prosthetic options available to dentists and patients. At the same time, there has been a steady and gradual corporatism of dental education and dental technology that appears to be irreversible. Voids in the existing dental delivery system have become apparent and require action from both the dental and dental technology communities. During my predoctoral training, students were given broad exposure to the technical aspects of prosthetic dentistry. They were expected to wax, invest and cast gold routinely, and make acrylic veneer bridges under the supervision of dental technicians and dentists, who served on the faculty at UB. Students also set their own denture teeth and processed acrylic resin for the partial and complete dentures provided in the predoctoral clinic. During each step, we interacted with real, live dental technicians. In the late ‘60s, graduating students predominately entered the military service. The military maintained a staff of dental technicians who were highly skilled and worked side by side with active dental officers to fabricate simple and complex dental restorations. Retiring military dental technicians opened commercial dental laboratories near military bases and were available to 16 NYSDJ • MARCH 2008

help with the fabrication of the restorations that were provided to military personnel and their families. Other dental technicians became faculty members in dental schools and dental technology programs throughout the country following their retirement from military service. Today, first-year dentists spend a fifth year of education in general practice residencies instead of going into military service. Getting to Know the Technology

As late as the early ‘70s, as an integral part of the educational process, pre- and postgraduate prosthodontic students were required to develop a basic level of dental laboratory skill, competence and attention to detail, as well as an understanding of how to fabricate restorations. The goal was to help students establish principles and learn to recognize standards of excellence for periodontal, occlusal and marginal adaptation, and substructure engineering considerations before treating clinical patients or fabricating prosthetics. Many faculty had either been laboratory technicians before becoming dentists or had developed a high degree of competence in dental technology. In my own postgraduate experience, at Tufts University, one of my mentors, Dr. Lloyd Miller, would bring the porcelain-fused-tometal cases he personally baked to school for us to see. Dental ceramics was in its infancy then. As time went on, postgraduate students were required to visit dental laboratories to meet and

establish communication with the dental technicians who produced the prosthetics the students would be placing in patients. Dr. Miller made sure all of his students visited Bob Welch and Lou Consoulis, two certified dental technicians at Dental Ceramics, Inc., the laboratory that made a significant portion of the fixed restorations the postdoctoral students delivered to patients treated in the postgraduate program. And Bob and Lou freely shared their experience and knowledge with us. They added to our ability to understand the state-of-the-art of dental technology available at the time and to make sure that new materials met established standards of biocompatibility, materials science and durability. In all, they enhanced our ability to do thoughtful case planning and treatment plans. We also learned the fundamental importance of careful tooth preparation, readable dies and appropriate mounting records, all of which enables technicians to perform to their best standards as well. Human Element is Gone

If you visit predoctoral programs today, you notice many changes. There has been a gradual virtualization and corporatism of the education experience. Students are given DVDs with all of the essential information they need to prepare for the regional dental examinations they will take at the end of their predoctoral training. Visits to the library have been replaced by a PDA or notebook computer. Mentors are gone, and there is less chance for students to develop independent curiosity and personal judgment. There is information overload, but also a simplification of information and the development of a market-based mentality. Many predoctoral programs require that their students keep track of their production figures in dollars instead of meeting the unit requirements and quality requirements of the past. Teachers of predoctoral students lament that there has been a shift in the curriculum, resulting in a reduction in the number of clock hours required for dental students in the area of prosthodontics and a virtualization of dental technology. As a result, students have never performed laboratory procedures, are not able to properly evaluate a prosthesis returned from the dental laboratory, have never met a dental technologist and have no sense of the value the dental technologist has in the delivery of dentistry. They are unaware that technologists are being forced to make decisions about product design that were typically a dentist’s responsibility. Adding to the market-based mentality of graduating dental students, many are leaving school with debt between $250,000 and $425,000 in education loans. Now, it’s no longer enough to make a living. One has to turn a profit. No wonder one of the first things these students do upon graduation is create a Web site to extol their excellence in all phases of dentistry—implants, orthodontics, cosmetic dental services—even though they have little actual training in these procedures. Preoccupied with meeting their loan payments, recent graduates have shifted emphasis from excellence to productivity and profitability.

The situation is not much different in postgraduate educational programs. In the school where I completed my training, I discovered that most if not all of the prosthetics that were delivered to patients were fabricated offshore in Thailand. That effectively reduced or eliminated the two-way communication between students and qualified dental technicians in the area. For many undergraduate and graduate students, interaction with dental technologists has been reduced to a box, a written prescription and a FedEx form. The obvious statement made here by dental school administrators is that the personal nature of a collaboration between dentistry and dental technology is of no value, nor is it good for the bottom line. Gone Forever?

The dentist/dental technician interaction within pre- and postdoctoral programs is not likely to be reinstated in the immediate future without a nationally mandated change in the predoctoral curriculum, according to dentists active in dental prosthetic education. Perhaps an educational module explaining dentists’ responsibilities upon graduation and the standards that have to be met must become part of predoctoral educational curriculum. There are similar problems in dental technology. The gradual Taylorization of the commercial dental technology business, the same philosophy used by Henry Ford to develop his automobile assembly line, has eroded the culture of artistic professionalism that used to characterize dental technology, turning it into an industry based upon productivity relying upon an assembly line model developed to create a profit. The supply of retiring militarytrained dental technologists has declined dramatically. And the number of accredited programs in dental technology has steadily dropped since 1990 from 60 to 20. The Department of Labor, Bureau of Labor Statistics, predicts that 11,000 out of the current 48,000 dental technicians will leave the profession by 2014. In that time, the accredited educational system will replenish that number by only 1,400. Outsourcing the fabrication of dental prosthetics to offshore laboratories will not solve this problem and may diminish our capacity to correct the manpower shortage by limiting our ability to recruit and sustain a workforce of educated dental technicians with a comprehensive knowledge of dental technology. It has also become a fact of life that dentists are less able to talk directly with the dental technologists who are fabricating restorations for dentists’ patients. Reducing the dental technician to a prescription and a case pan, eliminating the technician from the predoctoral dental educational experience has created a statement that could not be clearer. Public recognition of the essential collaboration that occurs between dentists and dental technicians is not occurring and should be addressed. The number of certified dental technicians (CDTs) has been steadily decreasing due to retirement, and these technicians are not being replaced adequately to meet present and future needs of their industry and those of dentistry. It is necessary NYSDJ • MARCH 2008 17

to acknowledge the professionalism of CDTs who have demonstrated a verifiable level of competence, established through the standardized testing and practical examination conducted by a national certification board. The American Dental Association has firmly established that dentists have the ultimate responsibility for deciding what is acceptable to be placed in the mouths of their patients and for safeguarding their patients’ health. In practice, however, dentists are relying more than ever on dental technologists to make decisions about the materials that will be placed in patients’ mouths. Often, these decisions are made without consultation with the dentist.Absent any state or federal mandate, there is no assurance or effective safeguard that the materials chosen for use in restorations fabricated by dental laboratories meet FDA standards, and the ability to track materials is severely limited. Bolstering the Image of Dentistry

The changes in the de facto responsibilities of dentistry and dental technology deserve consideration by individual dentists, educational programs, state governments and the ADA. Currently, dental laboratories are not licensed or regulated in New York State. There are no minimum standards or training required, no required demonstration of a verified level of competence, no license or regulation required for an individual to operate a dental laboratory in

New York State. There is no minimum or required amount of continuing education for dental technologists who are not certified dental technicians. CDT’s who have demonstrated a verifiable level of competence must be recognized for their accomplishments and professional commitment. They should be drawn upon to insure that acceptable standards are met and adhered to. Dentists should document specific materials contained in a manufactured prosthesis, as well as the country of its origin. Currently, more is known about the E. coli in the hamburger and spinach sold in a supermarket than about the materials contained in a dental prosthesis. There is no difference between contaminated medicines or food and a material used in a dental restoration that is potentially damaging to a patient’s health. Each should meet FDA standards and approval and be specified in the patient’s record for tracking purposes. In time, the memory of the basis upon which the credibility of dentists has rested, the collaborative efforts with dental technicians, the dedication to the best care possible for the patient’s health and welfare will fade and so will the prestige and trust that has served dentistry so well. There already has been a decline in professionalism in both dentistry and dental technology, replaced by a more market-based mentality that is coupled with a reduction in the quality-of-life experience in both areas. When dentistry becomes tangled in the bottom line, delivery of mediocre service will accurately define the image of the dentist. Despite what you may have read in advertisements, not everyone needs or can afford porcelain laminates or dental implants. But the need for conventional dentistry remains at an all-time high. Without highly dedicated and skilled dental technologists available nearby to discuss prosthetic design and delivery with dentists, the collaborative efforts of educated, knowledgeable and well-trained dentist/dental technologist teams will disappear, and this will have an impact on the quality of the oral health service provided. We must be the custodians of our profession and act positively on these issues. To begin addressing these changes in dentistry, modifications in the curriculum for predoctoral dental students need to be made to provide a clear description of the dentist’s responsibilities and the standards to be met when evaluating prosthetics to be placed in patients’ mouths. Also, recognition must be made of CDTs and their continuing education needs, as well as onthe-job training as a group and as responsible individuals who have demonstrated a verifiable level of competence and are essential collaborators in the dental practice. Licensure and regulation of dental laboratories statewide is a further step in the right direction deserving consideration. ■ Dr. Croll, a New York City prosthodontist, is executive director of the Dental Laboratory Summit, a group comprising representatives of the dental technology industry, dental and dental technology formal education programs, manufacturers and suppliers to dentistry and dental technology, the ADA, National Association of Dental Technology and publishing industry that is concerned with issues confronting dentistry and dental technology nationally and internationally.

18 NYSDJ • MARCH 2008

Stem Cells and the Future of Dental Care Jeremy J. Mao, D.D.S., Ph.D.

Abstract What are stem cells? As dentists, why should we be concerned with stem cells? How would stem cells change dental practice? Is it possible to grow a tooth or TMJ with stem cells? This article summarizes the latest stem cell research and development for dental, oral and craniofacial applications. Stem cell research and development will, over time, transform dental practice in a magnitude far greater than did amalgam or dental implants. Metallic alloys, composites and even titanium implants are not permanent solutions. In contrast, stem cell technology will generate native tissue analogs that are compatible with the patient’s own. 20 NYSDJ • MARCH 2008

STEM CELLS CAN BE DEFINED as cells that 1. self-replicate and 2. are able to differentiate into at least two different cell types. Both conditions must be present for a cell to be called a stem cell. For example, osteoblasts are not stem cells. Although osteoblasts differentiate into osteocytes, they typically do not differentiate into other cell types except osteocytes. Osteocytes are not stem cells; they are end-lineage cells that typically neither self-replicate nor differentiate. Different Types of Stem Cells

Embryonic stem cells (ES) refer to the cells of the inner cell mass of the blastocyst during embryonic development. ES are particularly notable for their two fundamental properties: the capacity to differentiate into any cell type in the body and the ability to self replicate for numerous generations (Lyons and Rao, 2007). One potential disadvantage of human ES, besides ethical issues, is precisely their virtually unlimited proliferation and differentiation capacity (Ryu et al., 2004). The clinically observed

teratoma is an example of ES growing into wrong tissues. To date, little attempt has been made towards the use of ES in dental, oral and craniofacial regeneration. Amniotic fluid-derived stem cells (AFS) can be isolated from aspirates of amniocentesis during genetic screening. An increasing number of studies have demonstrated that AFS have the capacity for remarkable proliferation and differentiation into multiple lineages, such as chondrocytes, adipocytes, osteoblasts, myocytes, endothelial cells, neuron-like cells and live cells (Barria et al., 2004; Prusa et al., 2004; De Gemmis et al., 2006; De Coppi et al., 2007; Kolambkar et al., 2007; Perin et al., 2007). The potential therapeutic value of AFS remains to be discovered. Umbilical cord stem cells (UCS) derive from the blood of the umbilical cord. There is growing interest in their capacity for selfreplication and multi-lineage differentiation (Laughlin et al. 2001). UCS have been differentiated into several cell types, such as cells of the liver, skeletal muscle, neural tissue and immune cells (Warnke et al.,

2004; Young et al. 2004). Their high capacity for multi-lineage differentiation is likely attributed to the possibility that UCS are chronologically closer derivatives of embryonic stem cells than adult stem cells. Several studies have shown the potential of UCS in treating cardiac and diabetic diseases in mice (Rebel et al. 1996; Tocci et al. 2003; Lee et al. 2005). UCS are neither embryonic stem cells, nor are they viewed as adult stem cells. Bone marrow-derived mesenchymal stem cells. When bone marrow is aspirated and cultured, a subset of adherent and mononuclear cells are mesenchymal stem cells (MSCs) (Alhadlaq and Mao, 2004; Marion and Mao, 2006). Bone marrowderived MSCs can self-replicate and have been differentiated, under experimental conditions, into osteoblasts, chondrocytes, myoblasts, adipocytes and other cell types, such as neuron-like cells, pancreatic islet beta cells, etc. (Alhadlaq and Mao, 2004; Kim et al., 2006; Marion and Mao, 2006). Bone marrow-derived MSCs are currently being investigated in broad applications, such as cartilage defects in arthritis, bone defects, adipose tissue grafts, cardiac infarcts, liver disease and neurological regeneration. MSCs are often viewed as a yardstick of adult stem cells. Tooth-derived stem cells (TS) are isolated from the dental pulp, periodontal ligament—including the apical region—and other tooth structures (Gronthos et al., 2000; Shi et al., 2001; Batouli et al., 2003; Miura et al., 2003; Mao et al., 2006). Craniofacial stem cells, including TS, originate from neural crest cells and mesenchymal cells during development (Zhang et al., 2006; Takashima et al., 2007). Neural crest cells share the same origin as progenitor cells that form the neural tissue. Conceptually, TS have the potential to differentiate into neural cell lineages. Indeed, TS from the deciduous tooth have been induced to express neural markers such as nestin (Miura et al., 2003). Similarly, bone marrow-derived stem cells also have been

induced to express neural cell markers (Kim et al., 2006). The expression of neural markers in TS elicits imagination of their potential use in neural regeneration, such as in the treatment of Parkinson’s disease. However, the expression of certain end cell lineage markers by stem cells only represents the first of many steps towards the treatment of a disease. In balance, the potential of TS in both dental and non-dental regeneration should be further explored. TS that have been isolated to date, either from deciduous teeth or permanent teeth, are considered postnatal stem cells or adult stem cells. Adipose-derived stem cells (AS) are typically isolated from lipectomy or liposuction aspirates.AS have been differentiated into adipocytes, chondrocytes, myocytes, neuronal and osteoblast lineages (De Ugarte et al., 2003; Zuk et al., 2002; Peptan et

al., 2006). AS can self-replicate for many passages without losing the ability to further differentiate (De Ugarte et al., 2003; Zuk et al., 2002; Gimble et al., 2007). Many believe that AS have advantages over other adult stem cell populations, for adipose tissue is abundant in certain individuals, readily accessible and replenishable. However, the ability to reconstitute tissues and organs by AS versus other adult stem cells has yet to be comprehensively documented. Induced pluripotent stem cells (iPS) refer to adult or somatic stem cells that have been coaxed to behave like embryonic stem cells. Recent reports have shown that the transduction of a small number of genes or transcription factors, as few as four, transforms adult fibroblasts into cells that proliferate and differentiate into ESlike cells. The four genes are Oct3/4, Sox2, Klf4, and c-Myc in Takahashi et al. (2007),

NYSDJ • MARCH 2008 21

but Oct4, Sox2, Nanog, and Lin28 in Yu et al. (2007). The biological and political implications of these studies are quite significant. On the biological front, the induced human somatic cells or iPS cells have the capacity to generate a large quantity of stem cells as an autologous cell source that can be used to regenerate patient-specific tissues. On the political front, iPS cells appear to minimize the need for human embryonic stem (ES) cells. However, even the authors of these recent reports have cautioned that any carcinogenic potential of iPS should be fully investigated before any commercialization can be realized. Stem Cells and Dental, Oral, Craniofacial Structures

Structures of interest to the dental profession include the enamel; dentin; dental pulp; cementum; periodontal ligament; craniofacial bones; the temporomandibular joint, including bone; fibrocartilage and ligaments; skeletal muscles and tendons; skin and subcutaneous soft tissue; and salivary gland. Without exception, all these dental, oral and craniofacial structures are formed by neural crest-derived and/or mesenchymal cells during native development. Since cells are the centerpiece of growing tissue or organs, the immediate question is how to get hold of the cells that generate dental, oral and craniofacial tissues? Among all possible stem cell sources, adult stem cells have a number of advantages over embryonic stem cells, umbilical cord stem cells and amniotic fluid stem cells for regeneration of many dental, oral and craniofacial structures. Adult stem cells are chronologically closer to the target dental, oral and craniofacial structures than embryonic stem cells, umbilical cord stem cells and amniotic fluid stem cells. Adult stem cells are not subjected to the ethical controversy associated with embryonic stem cells. Adult stem cells can be autologous and isolated from the patient, whereas embryonic stem cells cannot be autologous. It is also impossible for amniotic fluid stem cells or umbilical cord stem cells to be used as autologous cells until these cells are banked. The risk of immune rejection is 22 NYSDJ • MARCH 2008

Figure 1. A: Human mesenchymal stem cells (MSCs) isolated from anonymous adult human bone marrow donor following culture expansion (H&E staining). Further enrichment of MSCs can be accomplished by positive selection using cell surface markers, including STRO-1, CD133 (prominin, AC133), p75LNGFR (p75, low-affinity nerve growth factor receptor), CD29, CD44, CD90, CD105, c-kit, SH2 (CD105), SH3, SH4 (CD73), CD71, CD106, CD120a, CD124, and HLA-DR or negative selection (Alhadlaq and Mao, 2004; Marion and Mao, 2006). B: Chondrocytes derived from human mesenchymal stem cells showing positive staining to Alcian blue. Additional molecular and genetic markers can be used to further characterize MSC-derived chondrocytes (Alhadlaq and Mao, 2004; Marion and Mao, 2006). C: Osteoblasts derived from human mesenchymal stem cells showing positive von Kossa staining for calcium deposition (black) and active alkaline phosphatase enzyme (red). Additional molecular and genetic markers can be used to further characterize MSC-derived chondrocytes (Alhadlaq and Mao, 2004; Marion and Mao, 2006). D: Adipocytes derived from human mesenchymal stem cells showing positive Oil Red-O staining of intracellular lipids. Additional molecular and genetic markers can be used to further characterize MSC-derived chondrocytes (Alhadlaq and Mao, 2004; Marion and Mao, 2006).

present for non-autologous cells, whereas autologous stem cells are free from immune rejection. Bone marrow-derived, tooth-derived and adipose-derived stem cells, despite important differences among them, likely belong to subfamilies of mesenchymal stem cells (Marion and Mao, 2006; Gimble et al., 2007). Most dental, oral and craniofacial structures are connective tissue. During native development, dental, oral and craniofacial connective structures are formed by neural crest-derived and mesenchymal cells. Postnatally, clusters of mesenchymal cells continue to reside in various tissues and are the logical sources of adult mesenchymal stem cells (Marion and Mao, 2006).

MSCs can be isolated from the patient who needs treatment, and, therefore, they can be used autologously without immunorejection. MSCs have also been used allogeneically to heal large defects (Alhadlaq and Mao, 2004; Marion and Mao, 2006; Barrilleaux et al., 2006; Prockop, 2007). Figure 1 provides experimental data showing that a single population of mesenchymal stem cells can differentiate into chondrocytes, osteoblasts and adipocytes (Marion and Mao, 2006). Each of the differentiated cell lineages has implications in the treatment of a corresponding disorder. For example, MSC-derived chondrocytes can be used for reconstruction of orofacial cartilage structures, such as nasal cartilage and the temporomandibular joint. MSC-

derived osteoblasts can be used to regenerate oral and craniofacial bones. MSCderived myocytes can be used to treat muscular dystrophy and facial muscle atrophy. Stem cell-derived adipocytes can be used to generate soft tissue grafts for facial soft tissue reconstruction and augmentation. Stem Cells and Dental Practice

Patients come to the dentist because of infections, trauma, congenital anomalies or other diseases, such as orofacial cancer and salivary gland disorders. Caries and periodontal disease remain highly prevalent disorders among humans. Whereas native tissue is missing in congenital anomalies, diseases such as caries or tumor resection result in tissue defects. For centuries, dentistry has been devoted to healing defects with durable materials or the patient’s own (autologous) tissue. But we now realize that metallic alloys or synthetic materials are not permanent solutions (Rahaman and Mao, 2005). Amalgam, composites and even titanium dental implants can fail; and all have limited service time (Rahaman and Mao, 2005). Why are stem cells better than durable implants such as titanium dental implants? A short answer to this question is that stem cells lead to the regeneration of teeth with periodontal ligament that can remodel with the host. Why are stem cells superior to autologous tissue grafts? Autologous tissue grafting is based on the concept that a diseased or damaged tissue must be replaced by like tissue that is healthy. Thus, the key drawback of autologous tissue grafting is donor site trauma and morbidity. For example, we currently harvest healthy bone from the patient. We might take from the iliac crest, rib bone, chin or retro-molar area for bone grafting needs in cleft palate, ridge augmentation, sinus lifting, and maxillary and mandibular reconstruction. In contrast, stem cell-based therapeutic approaches may circumvent the key deficiencies of autologous bone grafting (Rahaman and Mao, 2005). Stem cells from a tiny amount of tissue, such as the dental pulp, can be multiplied or expanded poten-

The progress of stem cell-based technologies also depends on the regulatory pathways of the FDA in the United States and equivalent regulatory agencies elsewhere. tially to sufficient numbers for healing large, clinically relevant defects. Stem cells can differentiate into multiple cell lineages, thus providing the possibility that a common (stem) cell source can heal many tissues in the same patient, as opposed to the principle of harvesting healthy tissue to heal like tissue in association with autologous tissue grafting (Moioli et al., 2007). Stem cells can be seeded in biocompatible scaffolds in the shape of the anatomical structure that is to be replaced (Rahaman and Mao, 2005). Stem cells may elaborate and organize tissues in vivo, especially in the presence of vasculature. Finally, stem cells may regulate local and systemic immune reactions of the host in ways that favor tissue regeneration. When will each stem cell-based technology be available for dental and oral surgery practice? Some of the near-term applications, such as growth factor delivery, are approved or are being reviewed by the FDA, whereas others are being investigated at various stages of product development. However, it is impossible to provide the precise timeline of clinical application for a myriad of dental, oral and craniofacial diseases. Science does not progress linearly, and breakthrough is not always predicted. Furthermore, the progress of stem cellbased technologies also depends on the regulatory pathways of the FDA in the United States and equivalent regulatory agencies elsewhere. What can be predicted is that stem cell-generated tissue analogs will be available for clinical use for certain tissues before others.The first wave of this paradigm shift in dental health care is upon us now. The impact of this paradigm shift will eventually be present in every dental practice.

Physicians and scientists have recommended that umbilical cord stem cells and amniotic fluid stem cells be banked for potential application in the treatment of trauma and pathological disorders. Our understanding of mesenchymal stem cells in the tissue engineering of dental, oral and craniofacial structures has advanced tremendously (Krebsbach et al.,1999; Pittenger et al.,1999; Bianco et al., 2001; Alhadlaq and Mao, 2004; Mao et al., 2006; Marion and Mao, 2006).We have witnessed tissue engineering of the tooth, temporomandibular joint condyle, cranial sutures, soft tissue grafts, craniofacial bone, and other dental, oral and craniofacial structures in animal models (review: Mao et al., 2006). With all that we have learned about stem cells and tissue engineering of dental, oral and craniofacial structures, we are in a position to bring awareness to our patients regarding the proper storage of their extracted teeth in conditions that will preserve craniofacial stem cells, including toothderived stem cells. These include, but are not limited to, extracted wisdom teeth, extracted deciduous teeth, any teeth extracted for orthodontic purposes and any noninfected teeth extracted. Among postnatal tissues that are sources of stem cells that are obtainable without substantial trauma are extracted wisdom teeth, exfoliating or extracted deciduous teeth, teeth extracted for orthodontic treatment, trauma or periodontal disease. Craniofacial stem cells, including tooth-derived stem cells, have the potential, as do bone marrow-derived stem cells and adipose-derived stem cells, to cure a number of diseases that are relevant to dentistry as well as medicine, among them, diabetes, Parkinson’s disease and cardiac infarct. Is it Possible to Grow a Tooth or TMJ with Stem Cells?

As an example of craniofacial regeneration, we have used stem cells in the tissue engineering of a human-shaped temporomandibular joint using MSCs (Alhadlaq and Mao, 2003; Alhadlaq and Mao, 2005; Marion and Mao, 2006; Troken et al., 2007). Given that the mandibular condyle consists of two stratified layers of cartilaginous and bone tissues, NYSDJ • MARCH 2008 23

MSCs were first differentiated into chondrogenic and osteogenic cells (Alhadlaq and Mao, 2003; Alhadlaq et al., 2004). MSCderived chondrogenic and osteogenic cells were encapsulated in a biocompatible hydrogel in two stratified layers molded into the shape and dimensions of an adult human mandibular condyle (Alhadlaq and Mao, 2003; Alhadlaq et al., 2004). Following in vivo implantation in immunodeficient mice for up to 12 weeks, the retrieved mandibular joint condyles retained the shape and dimensions of the native condyle. The chondrogenic and osteogenic portions remained in their respective layers (Alhadlaq and Mao, 2005). The chondrogenic layer was positively stained by chrondrogenic marker, safarnin O, and contained type II collagen. In the interface between cartilaginous and osseous layers, there is a presence of hypertrophic chondrocytes that express type X collagen (Alhadlaq and Mao, 2005). In contrast, only the osteogenic markers, such as osteopontin and osteonectin, stained the osseous layer, but not the cartilage layer. Lastly and most importantly, there was mutual infiltration of the cartilaginous and osseous components into each other’s territory, which resembles mandibular condyle (Alhadlaq and Mao, 2005). Therefore, the proof of principle has been established to regenerate the human-shaped TMJ condyle. The tooth is a highly complex structure, with a level of complexity equal to that of internal organs, from the perspective of tissue engineering. Dental epithelial and mesenchymal cells isolated from rat or pig teeth have been seeded onto biodegradable scaffolds and implanted in immunodeficient mice. Several studies have shown that a tooth crown has been formed with different layers of enamel, dentin and pulp-like structures (Young et al., 2002; Duailibi et al., 2004; Sumita et al., 2006; Nakao et al., 2007). In vitro-generated tooth germ cells or stem cells have been transplanted into the adult tooth socket, leading to the formation of a tooth crown or root (Nakao et al., 2007; Sonoyama et al., 2007). Current efforts are occurring in several diverse directions, such as the use of sophisticated scaffold materials (Zhang et al., 2005, 24 NYSDJ • MARCH 2008

Moioli et al., 2007); the use of enriched dental stem cell populations (Laino et al., 2006; Shi et al., 2005; Sonoyama et al., 2006; Yen and Sharpe, 2006); and the use of specific dental epithelial and mesenchymal cell ratios and seeding (Hu et al., 2006; Honda et al., 2007). Overall, the proof of concept has been established to generate biologically derived tooth structures from stem cells. The remaining challenges are along several fronts, including scale up, accelerated tissue maturation and development of viable commercialization approaches. Summary

In the dental profession, we treat a myriad of trauma, congenital anomalies and diseases, including tissue defects resulting from dental caries, periodontal bone defects or facial bone defects. These defects not only lead to physical trauma and pain, but they also are detrimental to the psychosocial well-being of patients, given that the oral cavity and the face are intimately involved in self identity, communication and the expression of emotion. Current treatment approaches utilize the patient’s own tissues, allogeneic grafts, metallic alloys or synthetic implants. Much of what we know as dentists is evolving into a new dentistry in which dental care is delivered increasingly by biologically based approaches. For example, biomolecules will be used for periodontal regeneration; stem cells will be used in the regeneration of dentin and/or dental pulp; biologically viable scaffolds will be used to replace orofacial bone and cartilage; the defective salivary gland will be partially or completed regenerated (Rahaman and Mao, 2006; Mao et al., 2006; Mao et al., 2007). The challenge for the dental professional in the anticipated era of stem cells and tissue engineering is imminent. What would be a dentist’s response when patients ask whether they can get their own stem cells if they have their wisdom teeth banked? What are the odds that tooth stem cells will grow a new tooth or be used to treat diabetes? Should I use a growth factor called PDGF or BMP2 to treat my periodontal bone defects or have a bone graft? Should

my son’s baby teeth be banked for stem cells, and, if so, what are the odds that these baby teeth stem cells will cure a bone fracture he may get during a soccer game? The dental professional needs to be prepared to provide continuing education courses. Dental schools should consider the addition of stem cells and tissue engineering courses to the existing curriculum. Several textbooks are now available in the area of stem cells, tissue engineering and regenerative medicine (e.g. Mao et al., 2007).Without these and similar measures, dental students, postgraduate students and dental practitioners are likely to be ill-prepared for the upcoming era of stem cellbased technologies. Several well-established dental supply companies have established, or are establishing, R&D efforts in the area of stem cells and tissue engineering. Federal funding agencies, such as the National Institutes of Health, have been providing research and training grants on a competitive basis to the external research community in the area of stem cells, tissue engineering and regenerative medicine, including regenerative dental medicine, for over a decade (Wang et al., 2007). Strategies for education, training, research, development, commercialization and practice models need to be formulated and implemented. ■ Author’s acknowledgement: This article is dedicated to my teachers during my dental and specialty training, as well as my scientific training, for their intellectual influence and education. It is further dedicated to my previous and current students, residents, postdoctoral fellows and research scientists who have helped me to understand stem cells, tissue engineering and knowledge in general. The following research grants from the National Institutes of Health are gratefully acknowledged: DE15391, EB002332 and EB006261. Editor’s Note: Queries about this article can be sent to Dr. Mao at [email protected]. Copies of the extensive references that accompanied Dr. Mao’s manuscript are available upon request to The NYSDJ Managing Editor.

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Use of Metal Conditioner on Reinforcement Wires TO IMPROVE

DENTURE REPAIR STRENGTHS

Hiroshi Shimizu, D.D.S., Ph. D.; Nobuaki Mori, D.D.S.; Yutaka Takahashi D.D.S., Ph. D. Abstract The purpose of this study was to evaluate the transverse strength of denture base resin repaired with autopolymerizing resin and metal wire using a metal conditioner, along with the synergistic effect of a surface preparation for denture base resin. It was found that the use of Co-Cr-Ni wires air abraded with 50 µm alumina, followed by treatment with a metal conditioner and dichloromethane for denture base resin, was the most effective method for repairing fractured denture base resin.

ACRYLIC DENTURE BASE FRACTURE is an infrequent complication of denture care in clinical practice. Satisfactory repairs must be easy to make and performed promptly. They must also provide adequate repair strength. Among the reinforcement methods of denture repair reported to be in use, a common method involves the use of metal wires embedded with repair resin.1,2 The resin is easy to handle, rapidly polymerizes and is cost-effective, although its strength is still not sufficient. To gain optimum repair strength, it is essential for a good bond to exist between the metal wire and the repair resin, as well as between the denture base resin and the repair resin. 26 NYSDJ • MARCH 2008

The purpose of this study was to evaluate the transverse strength of denture base resin repaired with autopolymerizing resin and metal wire using a metal conditioner3-5 and to look at the synergistic effect of a surface preparation6-10 for denture base resin. Materials and Methods

Table 1 lists the materials used in this study. A total of 60 bar specimens (3.0 mm x 10.5 mm x 68.5 mm) of autopolymerizing denture base resin were prepared according to manufacturer’s instructions in a pressure-curing unit (SSKJ-50, Shofu, Inc., Kyoto, Japan) at 50 degrees C. and 0.39 MPa pressure for 10 minutes. After processing, the specimens were finished with No. 600 silicon-carbide abrasive paper under running water to final dimensions of 2.5 mm x 10.0 mm x 68.0 mm. They were then stored in 37-degree C. distilled water for one day. The 50 specimens were cut in half with a band saw under running water,guided by a standardized positional jig.The remaining 10 control specimens were not cut. The cut surfaces were made parallel to each other and perpendicular to the long axis of the specimens by abrading with No. 600 silicon-carbide abrasive paper under running water. The cut surfaces of the 10 randomly selected specimens were prepared using dichloromethane for 5 s for use as Group 5. The parallel halves of the specimens were placed in openended stone molds with the same dimensions as the original intact specimens. The molds were used so that the ends to be repaired could be fixed 3.0 mm apart, making a bar butt joint gap. This gap

TABLE 1 Materials Used Material

Product name

Manufacturer

Batch number

Denture base resin

Pour Resin PO

Shofu Inc., Kyoto, Japan

Powder 079255

Liquid 099201

Repair resin

Unifast #3

GC Corp., Tokyo, Japan

Powder 140722

Liquid 211022

Surface preparation agent

Dichloromethane

Nacalai Tesque, Inc., Kyoto, Japan

V2P6474

Metal wire

Sun-cobalt clasp-wire (␸=1.0 mm)

Dentsply-Sankin, Tokyo, Japan

C60215

Metal conditioner

Cesead II Opaque Primer

Kuraray Medical Inc., Tokyo, Japan

0036A

was then filled with the autopolymerizing acrylic repair resin. The mixing ratio (powder to liquid) was 2:1 (w/w). The free-flowing mix was poured into the joint space to allow for a slight excess, to ensure a complete joint. After processing, the repaired specimens were trimmed a little larger than their original dimensions. A steel bur (D 0023, Dentsply Maillefer, Ballaigues, Switzerland; ISO 027) was used under running water to grind a central groove (2.5 mm wide, 2.0 mm deep, 25 mm long) parallel to the long axis of the specimen into which the metal wires could be placed. A round CoCr-Ni wire (␸=1.0 mm) designed for clasps of removable partial dentures (Sun-cobalt clasp-wire, Dentsply-Sankin, Tokyo, Japan) was cut into 20 mm lengths. The specimens were divided into six groups: 1. without wires; 2. with untreated wires; 3. with wires treated with 50 µm alumina airabrasion (at a right angle to the surface from 5 mm distance for 10 s at an emission pressure of 0.48 MPa using a grit blaster [Microblaster, Comco Inc., Burbank, CA]); 4. with wires treated with 50 µm alumina airabrasion followed by application of a metal conditioner; 5.50 µm alumina air-abrasion of the wires, followed by application of metal conditioner on specimens whose cut surfaces and groove were prepared with dichloromethane; and 6. uncut intact group. After inserting the treated wires, the groove was filled with the autopolymerizing acrylic repair resin as described above except for the group 6 specimens. After the polymerization process was completed at 23 degrees C., the specimens were abraded under running water with No. 600 silicon-carbide abrasive paper to final dimensions of 2.5 (±0.03) mm x 10.0 (±0.03) mm x 68.0 mm. The completed specimens were then immersed in 37-degree C. distilled water for one day. A three-point bending test was used to determine the transverse strength of the test specimens using a screw-driven universal testing machine (TCM-200, Minebea Co. Ltd., Tokyo, Japan) at a crosshead speed of 1.0 mm/minute and with 60 mm between the supports during loading. A compressive load was applied to the center of the repaired site. The data were analyzed statistically using a one-way analysis of variance (ANOVA). The Tukey’s post-hoc comparison test was applied when appropriate (95% confidence level).

(p>0.05). The means and standard deviations of the transverse strengths for each group with statistical categories are summarized in Table 2. In most of the reinforced specimens, fractures occurred at the denture base resin/ autopolymerizing repair resin interface, and the wire held the two pieces of fractured specimens in position (Figure A). Two of the 10 specimens in group 5 broke into two pieces with fracture at one end of the wire (Figure B).

Results

Discussion

The one-way ANOVA and Tukey’s post-hoc comparisons test demonstrated that there were significant differences in the transverse strengths among the groups assessed (p3 % molybdenum, >3% tungsten, and