Influence of Dental Plaque on Human Enamel Erosion: In Situ/Ex Vivo Study

Purpose: The objective of the present in situ study was to evaluate the influence of dental plaque on human enamel erosion. Materials and Methods: Thirteen volunteers wore acrylic palatal devices with four enamel specimens that were prepared from freshly extracted impacted human third permanent molars (4 x 4 mm), randomly selected and distributed into two vertical rows, corresponding to the following groups: GI, erosion of dental plaque-free samples, and GII, erosion of dental plaque-covered samples. For the formation of dental plaque, the specimens were placed 1 mm below the level of the appliance and covered with a plastic mesh to allow the accumulation of dental plaque. The palatal device was continuously worn by the volunteers for 14 consecutive days and then immersed in a soft drink (Coca-Cola (R), 150 ml) for 5 min, three times a day. Half of the surfaces of specimens were coated with nail varnish for profilometry tests. The study variables included the depth of enamel surface wear (profilometer, vertical ranges in pm) and the percentage of superficial microhardness change (%SMHC). Data were analysed using the t test (P < 0.05). Results: The %SMHC and depth of enamel surface wear were significantly higher for GI (-87.82% +/- 3.66 and 4.70 mu m +/- 1.65) than for GII (-13.79% +/- 4.22 and 0.14 mu m +/- 0.03). Conclusions: It was concluded that the dental plaque formed in situ was able to protect the enamel surface against erosion by a cola soft drink, thus reducing the depth of enamel surface wear and the %SMHC.

Cephalometric evaluation in different phases of Jasper jumper therapy

Introduction: The aim of this study was to evaluate the dentoskeletal and soft-tissue effects of Class II malocclusion treatment with the Jasper jumper followed by Class II elastics at the different stages of therapy. Methods: The sample comprised 24 patients of both sexes (11 boys, 13 girls) with an initial age of 12.58 years, treated for a mean period of 2.15 years. Four lateral cephalograms were obtained of each patient in these stages of orthodontic treatment: at pretreatment (T1), after leveling and alignment (T2), after the use of the Jasper jumper appliance and before the use of Class II intermaxillary elastics (T3), and at posttreatment (T4). Thus, 3 treatment phases could be evaluated: leveling and alignment (T1-T2), use of the Jasper jumper (T2-T3), and use of Class II elastics (T3-T4). Dependent analysis of variance (ANOVA) and Tukey tests were used to compare the durations of the 3 treatment phases and for intragroup comparisons of the 4 treatment stages. Results: The alignment phase showed correction of the anteroposterior relationship, protrusion and labial inclination of the maxillary incisors, and reduction of overbite. The Jasper jumper phase demonstrated labial inclination, protrusion and intrusion of the mandibular incisors, mesialization and extrusion of the mandibular molars, reduction of overjet and overbite, molar relationship improvement, and reduction in facial convexity. The Class II elastics phase showed labial inclination of the maxillary incisors; retrusion, uprighting, and extrusion of the mandibular incisors; and overjet and overbite increases. Conclusions: The greatest amount of the Class II malocclusion anteroposterior discrepancy was corrected with the Jasper jumper appliance. Part of the correction was lost during Class II intermaxillary elastics use after use of the Jasper jumper appliance. (Am J Orthod Dentofacial Orthop 2011;140:e77-e84)

Preventive effect of an iron varnish on bovine enamel erosion in vitro

Objective: The aim of this study was to evaluate, in vitro, the effect of an experimental varnish containing iron on the dissolution of bovine enamel by carbonated beverage. Methods: Eighty specimens were randomly allocated to four groups (n = 20 per group), according to the following treatments: Fe varnish (FeV, 10 mmoL/L Fe), F varnish (FV, 2.71% F), placebo varnish (PV) and control (not treated, NT). The varnishes were applied in a thin layer and removed after 6 h. Then, the samples were submitted to six cycles, alternating re- and demineralisation (only 1 day). Demineralisation was performed with the beverage Coca-Cola (R) (10 min, 30 mL/block) and remineralisation with artificial saliva for I h. In order to determine the amount of enamel dissolved, the wear was analysed by profilometry. Data were analysed by ANOVA and Tukey`s test (p < 0.05). Results: The mean wear (+/- S.E.) was significantly lesser for the FeV (0.451 +/- 0.018 mu m) when compared to the other treatments. The FV caused significantly less wear (0.554 +/- 0.022 mu m) when compared to PV (0.991 +/- 0.039 mu m) and NT (1.014 +/- 0.033), which did not significantly differ from each other. Conclusions: The results suggest that the iron varnish can interfere with the dissolution of dental enamel in the presence of acidic beverages. (C) 2008 Elsevier Ltd. All rights reserved.

Light cola drink is less erosive than the regular one: An in situ/ex vivo study

Objective: This in situ/ex vivo study assessed the erosive potential of a light cola drink when compared to a regular one. Methods: During 2 experimental 14-days crossover phases, eight volunteers wore palatal devices with 2 human enamel blocks. The groups under study were: group light, erosive challenge with light cola drink and group regular, erosive challenge with regular cola drink. During 14 days, erosive challenges were performed extraorally 3X/day. In each challenge, the device was immersed in 150 ml of light cola (group light) or regular cola (group regular) for 5 min. Erosion was analysed by surface profilometry (mu m) and surface microhardness change (%SMH). The data were statistically analyzed using paired t test (p<0.05). Results: Group light (0.6 +/- 0.2 mu m) showed significantly lesser wear than group regular (3.1 +/- 1.0 mu m). There was no significant difference between the groups for the %SMH (group light -63.9 +/- 13.9 and group regular -78.5 +/- 12.7). Conclusions: The data suggest that the light cola drink is less erosive than the regular one. (C) 2008 Elsevier Ltd. All rights reserved.

Influence of cephalometric characteristics on the occlusal success rate of Class II malocclusions treated with 2-and 4-premolar extraction protocols

Introduction: The objectives of this investigation were to compare the initial cephalometric characteristics of complete Class II Division 1 malocclusions treated with 2 or 4 premolar extractions and to verify their influence on the occlusal success rate of these treatment protocols. Methods: A sample of 98 records from patients with complete Class II Division 1 malocclusion was divided into 2 groups with the following characteristics: group 1 consisted of 55 patients treated with 2 maxillary first premolar extractions at an initial mean age of 13.07 years; group 2 included 43 patients treated with 4 premolar extractions, with an initial mean age of 12.92 years. Initial and final occlusal statuses were evaluated on dental casts with Grainger`s treatment priority index (TPI), and the initial cephalometric characteristics were obtained from the pretreatment cephalograms. The initial cephalometric characteristics and the initial and final occlusal statuses of the groups were compared with the t test. A multiple regression analysis was used to evaluate the influence of all variables in the final TPI. Results: The 2-premolar extraction protocol provided a statistically smaller TPI and consequently a better occlusal success rate than the 4-premolar extraction protocol. The 4-premolar extraction group had statistically smaller apical base lengths, more vertical facial growth patterns, and greater hard- and soft-tissue convexities at pretreatment than the 2-premolar extraction group. However, the multiple regression analysis showed that only the extraction protocol was significantly associated with the final occlusal status. Conclusions: The initial cephalometric characteristics of the groups did not influence the occlusal success rate of these 2 treatment protocols.

In situ effect of an erosive challenge on different restorative materials and on enamel adjacent to these materials

Objectives: This in situ study evaluated the effect of an erosive challenge on different restorative materials and on enamel restored with these materials, as well as the ability of these materials to protect the adjacent enamel against erosion. Methods: Ten volunteers wore palatal devices with eight bovine enamel blocks, randomly selected and distributed into two vertical rows, corresponding to the following groups: GI/GV, resin-modified glass ionomer; GII/GVI, conventional glass ionomer; GIII/GVII, composite resin; GIV/GVIII, amalgam. one row (corresponding to groups I-IV) was immersed in a cola drink and the other row (corresponding to groups V-VIII) was subjected to saliva only. The palatal device was continuously worn for 7 days and only half of the appliance (groups I-IV) was immersed in the soft drink (Coca-Cola (R), 150 mL) for 5 min, three times a day. The study variables comprised the wear (profilometry, mu m) and the percentage of surface microhardness change (%SMHC). Data were tested for significant differences by two-way ANOVA and Tukey`s tests (p < 0.05). Results: Considering the restorative materials, for %SMHC and wear, there were no differences among the materials and between the saliva and the erosive challenge. For enamel analyses, the erosive challenge promoted a higher wear and %SMHC of the enamel than did the saliva. There were no significant differences in wear and %SMHC of the enamel adjacent to the different restorative materials. Conclusion: This research data suggest that there is little %SMHC and wear of the studied restorative materials and none of them had a preventive effect against erosion on adjacent enamel, which showed a pronounced wear. (c) 2007 Elsevier Ltd. All rights reserved.

An in situ/ex vivo comparison of the ability of regular and light colas to induce enamel wear when erosion is combined with abrasion

Objective: To evaluate whether the type of cola drink (regular or diet) could influence the wear of enamel subjected to erosion followed by brushing abrasion, Method and !Materials: Ten volunteers wore intraoral devices that each had eight bovine enamel blocks divided into four groups; ER, erosion with regular cola; EAR, erosion with regular cola plus abrasion; EL, erosion with light cola; and EAL, erosion with light cola plus abrasion, Each day for 1 week, half of each device was immersed in regular cola for 5 minutes, Then, two blocks were brushed using a fluoridated toothpaste and electric toothbrush for 30 seconds four times daily, Immediately after, the other half of the device was subjected to the same procedure using a light cola, The pH, calcium, phosphorus, and fluoride concentrations of the colas were analyzed using standard procedures, Enamel alterations were measured by profilometry. Data were tested using two-way ANOVA and Bonferroni test (P < .05), Results: Regarding chemical characteristics, light cola presented pH 3.0, 13.7 mg Ca/L, 15.5 mg P/L, and 0.31 mg F/L, while regular cola had pH 2.6, 32.1 mg Ca/L, 1:8.1 mg P/L, and 0.26 mg F/L, The light cola promoted less enamel loss (EL, 0.36 pm; EAL, 0.39 pm) than its regular counterpart (ER, 0.72 pm; EAR, 0.95 pm) for both conditions, There was not a significant difference (P > .05) between erosion and erosion plus abrasion for light cola, However, for regular cola, erosion plus abrasion resulted in higher enamel loss than erosion alone,.nclusion: The data suggest that light cola promoted less enamel wear even when erosion was followed by brushing abrasion, (Quintessence Int 2011;42:xxx-xx)()

Esthetic Analysis of Gingival Components of Smile and Degree of Satisfaction in Individuals With Cleft Lip and Palate

Objective: To evaluate soft tissue characteristics in individuals with cleft lip and palate and the degree of satisfaction of these individuals after rehabilitation. Setting: Hospital for Rehabilitation of Craniofacial Anomalies, Brazil. Patients: Forty-five individuals with repaired complete unilateral cleft lip and palate, aged 15 to 30 years. Interventions: One hundred thirty-five frontal facial photographs were obtained at rest and in natural and forced smile. Specialists in periodontics evaluated the soft tissue characteristics. Both patients and specialists evaluated the smiles and scored them as esthetically unpleasant, acceptable, or pleasant. Main Outcome Measures: Comparison of the cleft area with the contralateral region was performed for evaluation of soft tissue. The results of the degree of satisfaction with smile were expressed as percentages and means. The findings between patients and periodontists experienced or inexperienced with cleft care were compared. Results: Statistically significant differences were observed for alveolar process deficiency and absence of papilla in the esthetic area between groups (p < .05). Results show 84.4% of individuals considered their smile as esthetically pleasant. Specialists in periodontics of both groups scored the natural smile and forced smile as esthetically acceptable. There was a statistically significant difference in the mean of patients compared with both groups of specialists in periodontics (p < .05). Conclusions: Evaluation and knowledge of the soft tissue characteristics is extremely important for successful rehabilitation. The esthetic values and degree of patient satisfaction are essential for treatment success, since smile reconstruction should be esthetically pleasant to the patient.

A modified approach for vestibuloplasty in severely resorbed mandible using an implant-retained postoperative stent: a case report

Background. Severely resorbed mandibles often present a short band of keratinized tissue associated with a shallow vestibule. As a result, prominent muscle insertions are present, especially in the mental region of the mandible. This case report describes the deepening of the vestibular sulcus in an atrophic mandible by combining free gingival grafts harvested from the palate and a postoperative acrylic resin stent screwed on osseointegrated implants placed at the anterior region of the mandible. Study design. During the second-stage surgery, a split-thickness labial flap was reflected and apically sutured onto the periosteum. Two free gingival grafts were obtained and then sutured at this recipient site. A previously custom-made acrylic stent was then screwed onto the most distally positioned implants. To document the procedure`s stability over time, a metal ball was placed in the most apical part of the vestibule and standardized cephalometric radiographs were taken before and 6 months after the procedure. Linear measurements of vestibular depths over the observation time were realized using specific software for radiographic analysis. Results. The proposed technique augmented the band of attached masticatory mucosa, deepened the vestibule and prevented the muscle reinsertion. The difference between the 2 measurements of vestibular depths was 9.39 mm (initial 20.88 mm, final 11.49 mm) after a 6-month postoperative period. Conclusion. The technique, in combination with palatal mucosal graft and use of a postoperative stent, decreased the pull of mentalis muscle and provided a peri-implantally stable soft tissue around implants. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008; 106: e7-e14)

Cleft Palate Obturation With Branemark Protocol Implant-Supported Fixed Denture and Removable Obturator

A 41-year-old man with cleft palate presented with a wide dehiscence and missing teeth. Six implants had been placed for fabrication of an overdenture, which was unsatisfactory. A bar was waxed and cast for connection to the implants; precision attachments were placed laterally for retention. A fixed partial denture was fabricated, and milled crowns were fabricated at the molar region to provide a guiding plane for insertion of a removable palatal obturator. Good swallowing and speech outcomes were achieved. This technique provided functional and esthetic benefits, enhanced oral hygiene, and improved the psychological condition of the patient.

Effect of a single application of TiF(4) and NaF varnishes and solutions on dentin erosion in vitro

Objectives: This in vitro study aimed to analyse the effect of a single application of TiF(4) and NaF varnishes and solutions to protect against dentin erosion. Methods: Bovine root dentin samples were pre-treated with NaF-Duraphat varnish (2.26%F, pH 4.5), NaF/CaF(2)-Duofluorid varnish (5.63%F, pH 8.0), NaF-experimental varnish (2.45%F, pH 4.5), TiF(4)-experimental varnish (2.45%F, pH 1.2), NaF solution (2.26%F, pH 4.5), TiF(4) solution (2.45%F, pH 1.2) and placebo varnish (pH 5.0, no-F varnish control). Controls remained untreated. Ten samples in each group were then subjected to an erosive demineralisation (Sprite Zero, 4x 90 s/day) and remineralisation (artificial saliva, between the erosive cycles) cycling for S days. Dentin loss was measured profilometrically after pretreatment and after 1, 3 and 5 days of de-remineralisation cycling. The data were statistically analysed by two-way ANOVA and Bonferroni`s post hoc test (p < 0.05). Results: After pre-treatment, TiF(4) solution significantly induced surface loss (1.08 +/- 0.53 mu m). Only Duraphat reduced the dentin loss overtime, but it did not significantly differ from placebo varnish (at 3rd and 5th days) and TiF(4) varnish (at 3rd day). Conclusions: Duraphat varnish seems to be the best option to partially reduce dentin erosion. However, the maintenance of the effects of this treatment after successive erosive challenges is limited. (C) 2009 Elsevier Ltd. All rights reserved.

Influence of curing protocol on selected properties of light-curing polymers: Degree of conversion, volume contraction, elastic modulus, and glass transition temperature

Objectives. The purpose of this study was to investigate the effect of light-curing protocol on degree of conversion (DC), volume contraction (C), elastic modulus (E), and glass transition temperature (T(g)) as measured on a model polymer. It was a further aim to correlate the measured values with each other. Methods. Different light-curing protocols were used in order to investigate the influence of energy density (ED), power density (PD), and mode of cure on the properties. The modes of cure were continuous, pulse-delay, and stepped irradiation. DC was measured by Raman micro-spectroscopy. C was determined by pycnometry and a density column. E was measured by a dynamic mechanical analyzer (DMA), and T(g) was measured by differential scanning calorimetry (DSC). Data were submitted to two-and three-way ANOVA, and linear regression analyses. Results. ED, PD, and mode of cure influenced DC, C, E, and T(g) of the polymer. A significant positive correlation was found between ED and DC (r = 0.58), ED and E (r = 0.51), and ED and T(g) (r = 0.44). Taken together, ED and PD were significantly related to DC and E. The regression coefficient was positive for ED and negative for PD. Significant positive correlations were detected between DC and C (r = 0.54), DC and E (r = 0.61), and DC and T(g) (r = 0.53). Comparisons between continuous and pulse-delay modes of cure showed significant influence of mode of cure: pulse-delay curing resulted in decreased DC, decreased C, and decreased T(g). Influence of mode of cure, when comparing continuous and step modes of cure, was more ambiguous. A complex relationship exists between curing protocol, microstructure of the resin and the investigated properties. The overall performance of a composite is thus indirectly affected by the curing protocol adopted, and the desired reduction of C may be in fact a consequence of the decrease in DC. (C) 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.