Clinical Performance of Posterior Microhybrid Resin Composite Restorations Applied Using Regular and High-Power Mode Polymerization Protocols According to USPHS and SQUACE Criteria: 10-Year Randomized Controlled Split-Mouth Trial.

PURPOSE: This randomized, split-mouth clinical study evaluated the marginal quality of direct class-I and class-II restorations made of microhybrid composite that were applied using two polymerization protocols and two marginal evaluation criteria. MATERIALS AND METHODS: A total of 50 patients (mean age: 33 years) received 100 direct class-I or class-II restorations in premolars or molars. Three calibrated operators made the restorations. After conditioning the tooth with 2-step etch-and-rinse adhesive, restorations were made incrementally using microhybrid composite. Each layer was polymerized using a polymerization device operated either in regular mode (600-650 mW/cm2 for 20 s) (RM) or high-power (1200-1300 mW/cm2 for 10 s) mode (HPM). Two independent, calibrated operators evaluated the restorations 1 week (baseline) and 6 months after restoration placement, and thereafter annually up to 10 years using modified USPHS and SQUACE criteria. Data were analyzed using the Mann-Whitney U-test (α = 0.05). RESULTS: Alpha scores (USPHS) for marginal adaptation (76% and 74% for RM and HPM, respectively) and marginal discoloration (70% and 72%, for RM and HPM, respectively) did not show significant differences between the two polymerization protocols (p > 0.05). Alpha scores (SQUACE) for marginal adaptation (78% and 74% for RM and HPM, respectively) and marginal discoloration (70% for both RM and HPM) were also not significantly different at the 10-year year follow-up (p > 0.05). CONCLUSION: Regular and high-power polymerization protocols had no influence on the stability of marginal quality of the microhybrid composite tested up to 10 years. Both modified USPHS and SQUACE criteria confirmed that regardless of the polymerization mode, marginal quality of the restorations deteriorated significantly compared to baseline (p < 0.05).

Rotary versus reciprocating shaping files in bacterial elimination from long oval canals.

A comparison of the abilities of rotary versus reciprocating files to eliminate viable Enterococcus faecalis populations from the long oval root canals of extracted human teeth. Fifty teeth were contaminated and randomly distributed into two groups (n = 25 each): BT-RaCe group and WaveOne group. Two microbial samples were obtained from each tooth before (S1) and after (S2) instrumentation. The CFUs from the S1 and S2 measurements were calculated and compared between the groups. Both groups showed significantly fewer CFUs in the S2 samples (P < 0.001). In the S2 intragroup comparison, BT-RaCe resulted in significantly fewer CFUs than WaveOne (P = 0.010). In the direct comparison between the rotary multiple file shaping system and the reciprocating single-file system, the multiple file system was more efficient at reducing the microbiological load of viable E. faecalis from long oval root canals.

Microbiological characterization and effect of resin composites in cervical lesions.

BACKGROUND: Non carious cervical lesions associated to muscle hyperfunctions are increasing. Microhybrid resin composites are used to restore cervical abfractions. The purpose of this study was to investigate if resin composites modify tooth plaque, inducing an increment of cariogenic microflora and evaluate their effect, in vivo and in vitro, against S. mutans. MATERIAL AND METHODS: Eight abfractions were restored with two microhybrid resin composites (Venus, Heraeus-Kulzer® and Esthet-X, Dentsply®), after gnatological therapy, in three patients with muscle hyperfunctions. For each abfraction three samples of plaque were taken from the cervical perimeter: before the restoration, one week and three months after restoration. The samples were evaluated both by traditional microbiological methods and by Polymerase Chain Reaction (PCR). In vitro, disk-shaped specimens of the two composites were prepared to estimate the effects against pre-cultured S. mutans, after incubation at 37°C for 24h and assessed by a turbidimetric technique. RESULTS: In vivo no differences were found in plaque growth, for all samples, before and after restoration with both composites; in vitro, instead, a significant reduction of S. mutans growth was found between specimens of two composites (Mann-Whitney U-test p>0,06). CONCLUSIONS: In this study a relevant consideration was elicited: composite materials, in vivo, do not modify plaque composition of non carious cervical lesions to a potential cariogenic plaque. Key words:Abfraction, restoration, S. mutans, composite, class V.

Comparative analysis of SAF, Protaper Next and BT-Race in eliminating Enterococcus faecalis from long oval canals: An ex vivo study.

Comparison of the ability of newly designed rotary files to eliminate viable Enterococcus faecalis populations from long oval root canals of extracted human teeth to that of the self-adjusting file (SAF). One hundred caries-free, single-rooted, long oval teeth were contaminated with E. faecalis. The teeth were randomly distributed into four groups (n = 25) as follows: G.1, manual; G.2, SAF; G.3, ProTaper Next; and G.4, BT-Race. Two microbial samples were obtained from each tooth with sterile paper points, (s1) before and (s2) after instrumentation. The relative reduction in colony-forming units (CFUs) from s1 to s2 measurements was calculated and compared among the groups using parametric Kruskal-Wallis one-way anova on ranks and Dunn's method (a = 0.05). The results indicated a descending order of the groups with regard to efficacy as follows: BT-Race, Next, SAF and manual. The statistical analysis showed that the relative percentage reduction (RR) of CFUs was lower in the manual group than in the other groups, while the SAF group showed a significantly lower RR than the BT-Race group (P < 0.05). The efficacy in reduction of the microbiological load of viable E. faecalis from long oval root canals was different between the tested endodontic systems.

Indirect composite restorations luted with two different procedures: A ten years follow up clinical trial.

OBJECTIVES: The aim of this clinical trial was to evaluate posterior indirect composite resin restoration ten years after placement luted with two different procedures. STUDY DESIGN: In 23 patients 22 inlays/onlays (Group A) were luted using a dual-cured resin composite cement and 26 inlays/onlays (Group B) were luted using a light cured resin composite for a total of 48 Class I and Class II indirect composite resin inlays and onlays. The restorations were evaluated at 2 time points: 1) one week after placement (baseline evaluation) and 2) ten years after placement using the modified USPHS criteria. The Mann-Whitney and the Wilcoxon tests were used to examine the difference between the results of the baseline and 10 years evaluation for each criteria. RESULTS: Numerical but not statistically significant differences were noted on any of the recorded clinical parameters (p>0.05) between the inlay/onlays of Group A and Group B. 91% and 94 % of Group A and B respectively were rated as clinically acceptable in all the evaluated criteria ten years after clinical function. CONCLUSIONS: Within the limits of the study the results showed after ten years of function a comparable clinical performance of indirect composite resin inlays/onlays placed with a light cure or dual cure luting procedures. Key words:Light curing composite, dual curing composite, indirect composite restoration, inlays/onlays, clinical trial.

Effect of restorative, endodontic, and fatigue treatments on the cuspal deflection of maxillary premolars subjected to different cyclic occlusal forces: an in vitro study.

This study aimed to determine the effect of adhesive direct composite restorations, endodontic treatments, and fatigue treatments on the cuspal deflection of maxillary premolars subjected to different cyclic occlusal forces. Thirty intact maxillary second premolars were selected. Ten teeth were left untreated (group IN), 10 teeth were subjected to endodontic and restorative treatment (group FL), and the remaining 10 teeth were subjected to endodontic, restorative, and fatigue treatments (group FT). All teeth were subjected to 5 occlusal compressive loading forces (98, 147, 196, 245, and 294 N) with a universal testing device. A total of 15 experimental groups were obtained with 3 tooth conditions (IN, FL, FT) and 5 different occlusal loading values. Deflection amounts (µm) were measured with laser sensors and recorded, and obtained data were statistically analyzed with one-way analysis of variance at a significance level of .05. Mean cuspal deflection values (µm) and SDs of experimental groups ranged as follows: IN-98 (24.4 ± 19.8), IN-147 (34.8 ± 28.9), IN-196 (43.8 ± 34.7), IN-245 (54.5 ± 46.4), IN-294 (60.3 ± 50.6), FL-98 (56 ± 49.1), FL-147 (62.6 ± 49.6), FL-196 (72.4 ± 52.1), FL-245 (81.3 ± 56), FL-294 (92.2 ± 60.9), FT-98 (77.2 ± 80.9), FT-147 (83.4 ± 81.3), FT-196 (92.6 ± 83.7), FT-245 (102.7 ± 85.4), and FT-294 (124.2 ± 89.5). Mean values of three main experimental groups were as follows: IN (43.5 µm), FL (72.9 µm) and FT (96.0 µm). Significant differences were found between the three main groups and relevant subgroups (P < .001). Highest cuspal deflection values (CDV) were obtained in FT groups. Lowest CDV were obtained in IN groups. FL groups showed higher deflection values than IN groups. CDV increased progressively as the teeth were restored and subjected to fatigue treatment.

Marginal quality of posterior microhybrid resin composite restorations applied using two polymerisation protocols: 5-year randomised split mouth trial.

OBJECTIVES: This randomised, split-mouth clinical study evaluated the marginal quality of direct Class I and Class II restorations made of microhybrid composite and applied using two polymerisation protocols, using two margin evaluation criteria. METHODS: A total of 50 patients (mean age: 33 years) received 100 direct Class I or Class II restorations in premolars or molars. Three calibrated operators made the restorations. After conditioning the tooth with 2-step etch-and-rinse adhesive, restorations were made incrementally using microhybrid composite (Tetric EvoCeram). Each layer was polymerised using a polymerisation device operated either at regular mode (600-650 mW/cm(2) for 20s) (RM) or high-power (1200-1300 mW/cm(2) for 10s) mode (HPM). Two independent calibrated operators evaluated the restorations 1 week after restoration placement (baseline), at 6 months and thereafter annually up to 5 years using modified USPHS and SQUACE criteria. Data were analyzed using Mann-Whitney U-test (α=0.05). RESULTS: Alfa scores (USPHS) for marginal adaptation (86% and 88% for RM and HPM, respectively) and marginal discoloration (88% and 88%, for RM and HPM, respectively) did not show significant differences between the two-polymerisation protocols (p>0.05). Alfa scores (SQUACE) for marginal adaptation (88% and 88% for RM and HPM, respectively) and marginal discoloration (94% and 94%, for RM and HPM, respectively) were also not significantly different at 5th year (p>0.05). CONCLUSION: Regular and high-power polymerisation protocols had no influence on the marginal quality of the microhybrid composite tested up to 5 years. Both modified USPHS and SQUACE criteria confirmed that regardless of the polymerisation mode, marginal quality of the restorations deteriorated compared to baseline.

New resin composites used to restore both anterior and posterior teeth.

Over the last few years, the advancements made in the field of adhesive techniques have significantly modified operative techniques, from cavity preparation to final restoration. On one hand, a predictable bond between restoration and dental tissues allows us to operate with very conservative techniques, saving sound dental tissue; on the other hand, it must be considered that such procedures are not simple. Additionally, it is easy to observe that all of our everyday dental practice is strictly influenced by the type of material and techniques used. Knowing such procedures as well as adhesive mechanisms, quality of sound dental tissue and its conservation - both in vital and endodontically treated teeth - is now considered significantly relevant for restorative purposes.