streptococcus mutans group, there was significant difference between Groups C ... also verified on the vestibular surface of teeth, followed by the interproximal ...
RESEARCH Streptococcus Mutans Group And Lactobacillus Counts In Proximal Amalgam And Resin Composite Restorations: An In Vivo Study Juliana Campos Junqueira,1 Alessandra Bühler Borges,2 Daphne Câmara Barcellos,3 Cinthya Lobo Pradella,4 Antonio Olavo Cardoso Jorge,5 Carlos Rocha Gomes Torres6 capable of adhering to the surface of the dental enamel, they are mainly responsible for the initial phase of caries lesion. These microorganisms have been strongly associated with the increase in the risk of Aim & Objectives: This study assesses the quantity of caries when detected in high numbers in the saliva (2). streptococcus mutans group and lactobacillus in interproximal As lactobacillus has a lower capacity to adhere to the contact of posterior teeth with proximal amalgam and resin composite restorations. tooth surface, they are more associated with the Methods: Twenty patients were divided into two groups (n=10) subsequent development of the lesion (2). However, according to the type of restorative material they presented: the lactobacillus count may also be used as predictive of amalgam (AM) or resin composite (RC). In the same patient, one caries and the increase in the number of these interproximal Class II amalgam or resin composite restoration and microorganisms is related to the risk of caries(3). one interproximal contact without restorations (control group – The quantity of microorganisms varies C) were studied. The material was collected from the according to the location assessed in the oral cavity. interproximal with the aid of a piece of sterilized dental thread, The highest number of microorganisms is found in the and stored in phosphate buffered saline solution. The material biofilm of molars, followed by pre-molars and anterior was seeded on plates containing Mitis Salivarius Bacitracin Sucrose agar and Rogosa agar culture medium and incubated at teeth(3,4). Greater colonization by microorganisms is 37C for 48-72h. The colony forming units (Log10 CFU/mL) were also verified on the vestibular surface of teeth, followed counted2and the data were submitted to the Student’s-t test (5%). 3 4 Patri, Yoshaskam Agnihotri, S.Balagopal by the interproximal, occlusal and lingual faces (4). Results: There was significant difference between Groups C and According to Lindquist and Emilson (5) (1990), the AM (p=0.019) with regard to lactobacillus count. For surfaces of teeth with restorations are shown to be streptococcus mutans group, there was significant difference more colonized by microorganisms than the healthy between Groups C and RC (p=0.015). faces (6). Conclusion: There is significantly greater growth of streptococcus The principal etiologic agents that initiate and mutans group in RC Class II restorations and lactobacillus in AM propagate dental diseases are permanent inhabitants of restorations when compared with interproximal contact without the biofilm formed on teeth and restorations. Dental the presence of restorations. materials release different substances, which might be KeyWords: Biofilms, lactobacillus, restorative materials, able to influence the growth of bacteria directly (7). streptococcus mutans group. Thus, in view of the above discussion, the aim of this in vivo study was to correlate the number of streptococcus mutans group and lactobacillus in amalgam and resin composite restorations in the Introduction interproximal contact of posterior teeth. The null Dental caries is a multifactorial disease, hypothesis tested was that the streptococcus mutans requiring a susceptible host, a cariogenic microbiota group and lactobacillus counts do not differ in teeth and an acidogenic substrate, which must be present in with amalgam and resin composite restorations when the mouth for a sufficient length of time and interact compared with healthy teeth. under critical conditions (1). Microbiological techniques to detect cariogenic microorganisms enable the early detection of individuals with a high risk of caries. The Materials and Method microbiological factors that have been studied are mainly concerned with the number of streptococcus mutans group and lactobacillus in dental biofilm or This study was approved by the Research Ethics saliva (1). Committee of the São Jose dos Campos School of Because the streptococcus mutans group is Dentistry - UNESP (Protocol No. 082/2004-PH/CEP). capable of adhering to the surface of the dental Twenty patients between the ages of 18 and 50 IJCD • AUGUST, 2011 • 2(4) 80 enamel, they are mainly responsible for the initial phase years, under treatment at the Restorative Dentistry © 2011 Int. Journal of Contemporary Dentistry of caries lesion. These microorganisms have been clinic of the São José dos Campos/UNESP Faculty of
ABSTRACT
RESEARCH Twenty patients between the ages of 18 and 50 years, under treatment at the Restorative Dentistry clinic of the São José dos Campos/UNESP School of Dentistry participated in this study. They were divided into 2 groups: 10 patients with Class II amalgam restorations and 10 patients with Class II resin composite restorations. In the same patient, one interproximal contact with a restoration and one interproximal contact without restorations (Control) were analyzed (Table 1).
DS4-BI, Biosystems, Curitiba, PR, Brazil). The lactobacillus count was performed observing the characteristic discoid colonies. The number of characteristic colonies in each medium was counted and the value of the logarithm of colony forming units per milliliter (log10 CFU/ml) was calculated. The data obtained were submitted to Student’st test for two samples, considering a significant difference when p 0.05.
To assign the control group, one interproximal contact corresponding to the same patient assessed with Class II restorations was selected in the opposite hemi-arch of the same patient.
Results
All restorations were present in the oral cavity for at least 2 months, showing criteria for satisfactory restoration in accordance with the USPHS criteria, with regard to retention, marginal adaptation, color match, marginal discoloration, sensitivity, recurrent caries and surface roughness. Radiographs were taken of the all restorations to excluded Class II restoration that showed radiolucent defects. The material from the interproximal contact of patients was collected with the aid of a piece of dental floss (50cm) sterilized in an autoclave (121C/15 minutes). In the center of the piece of dental floss, a 1 cm space was demarcated with a ball pen before sterilization. For all the interproximal contacts, the delimitated area of the dental floss was passed over the interproximal contact, to pick up all possible plaque in the area by wrapping around the line angles of restoration margins. After this, it was cut with sterilized scissors in the previously demarcated area and was inserted into a test tube with 3 mL of sterilized phosphate buffered (PBS 0.1 M and pH 7.2) saline solution (0.9% NaCl). After this, the tube was submitted to agitation for 2 minutes in a Tube Agitator (Vortex Model 251, Exair Corporation, Cincinnati, OH, USA) to obtain a uniform suspension. Next, the suspension was submitted to decimal dilutions of 10-1, 10-2 and 10-3. To seed the streptococcus mutans group, aliquots of 0.1 mL of each dilution were deposited in duplicate on Petri plates with the Mitis Salivarius Agar culture medium (Difco Laboratories, Detroit, MI, USA) in addition to bacitracin (0.2 U.I. per mL of medium) and 15% sucrose. The deposited material was uniformly distributed on the surface of the culture medium with the aid of a Drigalski loop. After this, the plates were incubated in CO2 at 37C for 48 hours. To seed the lactobacillus, aliquots of 0.1 mL of pure solution and 10-1 and 10-2 dilutions were seeded on pour plates in Petri dishes containing Rogosa agar (Difco Laboratories, Detroit, MI, USA). The plates were incubated at 37 C for 72 hours. The characteristic streptococcus mutans group colonies were observed and counted under reflected light with the aid of a stereomicroscope (Medilux, MDL-
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In the results shown in Table 2, it was observed that for the lactobacillus microorganism, there was a significant difference (p=0.019) between the control group and Class II amalgam group, however, the other groups did not differ with regard to mean values in the log10 scale. In the results shown in Table 3, it was observed that for the streptococcus mutans group, there was a significant difference (p=0.015) between control group and Class II resin composite group. In the other groups, there was no difference among the mean values in the log scale, however, they obtained a value close to the level of significance of 5% (p=0.0586).
Discussion Since microbiota is one of the essential factors in the etiology of caries, endeavors to obtain a suitable method for predicting caries risk have turned increasingly to the use of microbiological tests (9). Lactobacillus is correlated to the progression of the carious process because it has a low capacity of adherence to the tooth surface (10). The streptococcus mutans group is the bacteria more closely associated with dental caries in enamel, being responsible mainly for the initial phase of the lesion (11). Different types of biofilm may be formed, because the constitution of the surface and its roughness interfere in the initial adherence of microorganisms which, after several successive microbial events, will determine the resulting microbiata of the biofilm (12). The surface smoothness of the restorative material, resulting from finishing and polishing, and marginal adaptation to the cervical wall are fundamentally important to avoid greater accumulation of bacterial plaque (biofilm) (13). The patient’s control of bacterial plaque in these regions of restored teeth must be facilitated, and the restoration must not be a plaque retentive factor. In this study, it was observed that for the streptococcus mutans group, Class II resin composite restorations showed statistically higher values of log10 (CFU/ml) when compared with the interproximal
IJCD • AUGUST, 2011 • 2(4) © 2011 Int. Journal of Contemporary Dentistry
RESEARCH Table 1: Distribution of patients and interproximal spaces in different experimental groups
Groups
Number of patients
Interproximal space condition
Number of interproximal spaces
Amalgam
10
Resin Composite
10
Restoration Without restoration Restoration Without restoration
Total
20
10 10 10 10 40
Table 2: Mean and standard deviation values and results of t-test for resin and amalgam groups (Lactobacillus).
Lactobacillus
Group Control Resin Control Amalgam
Mean ± SD t-value 0.56 ± 1.34 -1.09 1.26 ± 1.51 0.75 ± 1.22 -2.84 2.61 ± 1.67 *significant difference (p
