The role of the dentist in the diagnosis, screening and followup of lesions of the oral mucosa

The early detection and follow up of oral mucosa lesions are a must for every dentist. The importance of these activities is tremendous for oral cancerous and precancerous lesions, so every dentist is officially responsible for this important role in the public health. The modalities of such early detection and follow up are described.     

Influence of thermal and mechanical load cycling on microtensile bond strengths of total and self-etching adhesive systems

This study evaluated the influence of different thermal (TC) and mechanical (MC) cycling protocols on microtensile bond strength (muTBS) to cervical dentin margins of Class II restorations using two total-etch (TE) adhesives and one self-etching (SE) primer. Class II slot cavities were prepared on the mesial surfaces of 168 bovine incisors and were divided into three groups according to the bonding system used: Single Bond, OptiBond Solo Plus and Clearfil SE Bond. All cavities were restored with Filtek Z250 composite. Following restorative procedures, the restored teeth were allocated to seven subgroups (n = 8) according to the thermal/mechanical protocol performed: G1-control (no cycling), G2-100,000 MC, G3-200,000 MC, G4-500,000 MC, G5-100,000 MC+1,000 TC, G6-200,000 MC+1,000 TC, G7-500,000 MC+1,000 TC. TC was performed using 5 +/- 2 degrees C and 55 +/- 2 degrees C baths, with a dwell time of 60 seconds in each bath. MC was achieved with an axial force of 80 N at 2 cycles/second. The restorations were sectioned perpendicular to the cervical bonded interface into two 0.8-1-mm thick slabs. The slabs were trimmed at the interface to obtain a cross-sectional surface area of 0.8-1 mm2. All specimens were then subjected to muTBS (v = 0.5 mm/minute). Fracture mode analysis was performed using SEM. Bond strength mean values (MPa) were analyzed with ANOVA 3-way and Tukey's test (alpha = 5%). Dunnett's test was used to compare tested groups against Control groups of each adhesive system (alpha = 56%). SE primer presented lower mean bond strength values when compared to TE adhesives (p = 0.05). In addition, specimens restored with the SE primer did not resist to the 200,000 and 500,000 MC associated with TC. The application of 100,000 MC did not present a significant decrease in bond strength when compared to the control. Mixed failures were predominant for all groups. The higher the amount of thermal/mechanical cycles, the greater the number of mixed failures and the lower the percentage of adhesive failures.     

Microtensile bond strength of self-adhesive luting cements to ceramic

PURPOSE: To test the null hypothesis that three self-adhesive luting materials had the same microtensile bond strength when used to lute ceramic IPS Empress II disks to the dentin of perfused teeth. MATERIALS AND METHODS: Occlusal enamel and the roots of 9 human third molars were removed and crown segments connected to a perfusion system (30 cm H2O). Nine ceramic disks (IPS Empress II) were prepared, conditioned with 5% HF (20 s), rinsed with water, and air dried. A primer silane agent was applied (Monobond-S) for 60 s and air dried. Teeth were bonded to disks using one of three materials: Multilink System, RelyX Unicem, or Panavia F light. Specimens were vertically sectioned to obtain square bars. Each bar was fixed to a rigid custom-made tensile device and submitted to tensile force until debonding. Microtensile bond strength (microTBS) was given in MPa. Because the means of bonded areas (BA) were different between groups, it was impossible to compare microTBS results directly. Thus, the regression line TBS(MPa) = -2.15 + [19.92 / BA (mm(2))] was calculated to correlate microTBS results and BA. Residuals (difference between the value estimated by the regression line and the actual value) were stored as "distances". ANOVA was performed to examine the statistical significance of differences between means distances of the groups', and the Tamhane's post hoc test was used to locate eventual differences. RESULTS: The number of bars used in the analysis was n = 147. Residuals should not be statistically different if the null hypothesis (represented by the regression line) was credible. ANOVA showed statistically significant differences between the distances of the groups' means (p < 0.00001). Tamhane's post hoc test (p < 0.05) showed that different group means were RelyX < Multilink < Panavia F. CONCLUSION: The null hypothesis was rejected: materials showed different tensile bond strengths. Panavia F obtained highest bonding values, followed by Multilink System. RelyX Unicem, the only material that does not require pretreatment of dentin, achieved the lowest TBS values under these study conditions.     

Microhardness of resin-based materials polymerized with LED and halogen curing units

The purpose of this study was to evaluate the microhardness of resin-based materials polymerized with a LED (light-emitting diode) light-curing unit (LCU) and a halogen LCU. Twenty cylindrical specimens (3.0 mm in diameter and 2.0 mm high) were prepared for each tested material (Z100, Definite and Dyract). Specimens were light-cured with two LCUs (Ultraled and Curing Light 2500) for either 40 or 60 s on their top surfaces. Hardness was measured on top and bottom surfaces of each specimen. Statistical analysis was done by ANOVA and Tukey's test (p<0.05). There was no significant difference in hardness between LED LCU and halogen LCU for Z100 and Dyract on top surface. Conversely, lower hardness was recorded when Definite was light-cured with the LED LCU than with the halogen lamp. On bottom surface, hardness was significantly lower for all materials light-cured with LED LCU. Z100 was harder than Dyract and Definite regardless of the light curing unit. There was no significant difference in hardness between the exposure times on top surface. Higher hardness was obtained when the materials were light-cured for 60 s on bottom surface. The tested LED was not able to produce the same microhardness of resin-based materials as the halogen LCU.     

Analysis of the condyle/fossa relationship before and after prosthetic rehabilitation with maxillary complete denture and mandibular removable partial denture

STATEMENT OF PROBLEM: The influence of the loss of posterior teeth on the condylar position and on temporomandibular disorders (TMDs) remains a controversial issue. PURPOSE: This study investigated whether prosthetic rehabilitation promoted modification of the condylar position in subjects without symptoms of TMDs. MATERIAL AND METHODS: The temporomandibular joints (TMJs) of 12 women (age 37 to 74), all with existing maxillary complete dentures but no removable partial denture (RPD) restoring the Kennedy class I partially edentulous mandibular arch and no clinical signs of TMDs according to the criteria established by Helkimo, were viewed in maximal intercuspal position with corrected lateral tomography before and after prosthetic rehabilitation with a new maxillary complete denture and a mandibular RPD. Before prosthetic rehabilitation, a mandibular stabilizing base was fabricated to prevent the existing maxillary complete denture from dislodging during tomographic examination. Two methods were used to evaluate tomograms: (1) linear measurements of the subjective narrowest anterior and posterior intra-articular joint spaces made from the tomograms by use of a digital caliper and (2) linear measurements of the anterior and posterior intra-articular joint spaces on the basis of drawings and tracings. Repeated-measures analysis of variance followed by orthogonal contrasts were used to evaluate differences between measurements carried out on the same subject under the different test conditions of the study (before prosthetic rehabilitation, before prosthetic rehabilitation with a mandibular stabilizing base in position, and after prosthetic rehabilitation) (P<.05). RESULTS: Before prosthetic rehabilitation, a predominance of posterior condylar positions was observed. Before prosthetic rehabilitation with a mandibular stabilizing base in position, a significant decrease was observed in posterior condylar positions (P=.03). This decrease was more marked after prosthetic rehabilitation (P=.02). The subjective evaluation and comparison on the basis of drawings and tracings used to analyze the tomograms produced similar results (P=.70). CONCLUSION: Within the limitations of this study, significant changes in the condylar position occurred after prosthetic rehabilitation in subjects without symptoms of TMDs.     

Conversion from cyclosporin A to tacrolimus as a non-surgical alternative to reduce gingival enlargement: a preliminary case series

BACKGROUND: Gingival enlargement (GE) is a frequent side effect that occurs in organ transplant recipients (OTR) after the administration of cyclosporin A (CsA). The availability of new drugs used to suppress graft rejection in OTR offers an opportunity to manage GE non-surgically. This preliminary case series aimed to analyze the effect of CsA withdrawal and its substitution by another immunosuppressant in OTR with severe GE. METHODS: Four organ transplant recipients who had received a liver or renal allograft were recruited for this study. All OTR had developed clinically severe CsA-induced GE. GE scores were assessed for each patient at baseline and at weeks 2, 4, 8, 12, 16, and 54 following conversion to tacrolimus. Scaling and root planing were initially performed and repeated monthly during the first 6 months. Careful polishing of the teeth was carried out once every 2 weeks until month 6 and then monthly until month 12. Hygiene instructions and reinforcement to optimize oral hygiene were maintained throughout the study. RESULTS: The four patients showed a rapid decrease in their gingival symptoms and in the size of the gingivae. This change was clinically evident 8 weeks after conversion to tacrolimus. One year later, all the patients experienced GE regression, although some anatomic irregularities persisted in the interdental papillae of one of the patients. No adverse effects from tacrolimus were observed during the study except in one patient who presented headaches. CONCLUSION: It seems that CsA withdrawal and its conversion to tacrolimus in organ transplant recipients who develop severe gingival enlargement, together with an extensive plaque control program, provide an effective means to control/eliminate gingival hyperplasia, with minimal risk of graft dysfunction.     

Measuring inequalities in the distribution of dental caries

Abstract – Objectives: To evaluate different measurements of prevalence and inequality in the distribution of dental caries as to their partial collinearity, and ability in expressing associations with the supply of fluoridated tap water, indices of socioeconomic status and provision of dental services. Methods: The DMFT, the Significant Caries (SiC) Index, the proportions of children with high- (DMFT ≥ 4) and rampant- (DMFT ≥ 7) caries experience, caries-free children (DMFT = 0), the Gini coefficient and the Dental Health Inequality Index (DHII) were the dental outcomes appraised in a sample comprising 18 718 oral examination records for 11- and 12-year-old schoolchildren in 131 towns of the state of São Paulo, Brazil. Spatial data analysis assessed the association between aggregate figures of dental indices and several covariates. Results: The DMFT, the SiC Index and the proportions of children with high- and rampant-caries experience presented strong linear associations (Pearson r near or higher than 0.95), and an analogous profile of correlation with indicators of socioeconomic status, dental services and access to fluoride tap water. The same was observed for the DHII, the Gini coefficient and the proportion of caries-free children. These observations involve the perception of variables in each set as interchangeable tools for ecological studies assessing factors influencing, respectively, prevalence levels and inequality in the distribution of dental disease. Conclusion: An improved characterization of the skewed distribution of caries experience demands the concurrent estimation of figures of prevalence and inequality in dental outcomes. This strategy may contribute to the design of socially appropriate programmes of oral health promotion.     

PATTERN OF DISOCCLUSION IN PATIENTS WITH COMPLETE CLEFT LIP AND PALATE

Objective:

to analyze the pattern of disocclusion during excursive mandibular movements and presence or absence of occlusal interferences and occlusal pathologies (gingival recession and abfraction).

Method:

examination of 120 individuals divided into two groups, as follows: Group 1-90 patients with complete cleft lip and palate (study group), subdivided into 30 patients with complete left unilateral cleft lip and palate, 30 patients with complete right unilateral cleft lip and palate and 30 patients with complete bilateral cleft lip and palate; Group 2-30 individuals without clefts (control group).

Results:

58.8% of patients in Group 1 presented unilateral or bilateral canine guidance, 26.6% presented unilateral or bilateral group function and 54.4% presented lateral movements through the posterior teeth. Regarding protrusive movements, 80% presented anterior guidance and 20% presented posterior guidance. In Group 2, 69.6% of individuals presented unilateral or bilateral canine guidance, 43.2% presented unilateral or bilateral group function and only 13.3% presented lateral movements through the posterior teeth; 3.4% presented protrusion through the posterior teeth.

Conclusions:

there was no difference in the pattern of disocclusion between subgroups of patients with clefts. Group 2 presented predominance of bilateral group function, whereas Group 1 presented a higher prevalence of posterior guidance during lateral movements. Protrusion occurred primarily through anterior guidance in Group 2 and through the posterior teeth in Group 1. There was high prevalence of occlusal interferences at the molar area for both groups, yet with no correlation with occlusal pathologies (recession and abfraction).