Quintessence International, 01/2005

Modern dentistry aims to preserve tooth structure using minimally invasive procedures. Chemomechanical removal of caries is a new method with the advantage of selective removal of severely demineralized dentin. In addition, the method enhances the clinician's ability to diagnose caries. Ensuring chairside caries diagnosis and removal, based on biologic principle, helps to preserve as much healthy tissue as possible. However, while this method is most comfortable for the patient, treatment time is prolonged. In most cases, the method has to be used in combination with a conventional bur. Also, caries lesions in which removal of enamel or a restoration is needed cannot be treated exclusively using the chemomechanical method. This article describes the mechanism of action of the chemomechanical method (CarisolvTM) for caries removal. Indications for use of the chemomechanical method as a first-choice treatment are presented. Clinical cases in which this new approach provides a significant clinical advantage are also described. Keywords: chemomechanical excavation, dental caries, mechanical excavation

This in situ study evaluated the influence of two home-use tooth bleaching regimes (1 hour/day and 7 hours/day) using 10% carbamide peroxide (Nite White Excel 2Z) on the surface microhardness of dentin over a 21-day period. Nine blocks of dentin derived from the teeth of subjects, each with at least two thirds molar in need of extraction, were obtained from the cervical region and submitted to surface-hardness analysis (Shimadsu HMV/2000), fixed to an intraoral palate device fabricated for each subject, and positioned (3 left side, 3 right side, 3 center) according to experimental group. During the bleaching period, casts bearing the whitening agent were applied to the blocks for 7, 1, and 0 hours, respectively (7 left side, 3 right side, 0 center). After the treatment period, the specimens were once again submitted to microhardness analysis, using the same equipment as before, and then analysis of variance and the Scheffé test were applied to the mean differences between the initial and final evaluations. The results demonstrated that the statistical difference between the 1-hour and 7-hour groups was not significant. However, the 7- hour group, when compared with the control group, demonstrated statistically significant differences with a reduction in microhardness. Despite the occurrence of mineral loss in the 1-hour and 7-hour groups, this difference was only 3.1% and 5.4%, respectively, which allows one to conclude that these values probably have no clinical significance. Keywords: bleaching, dentin, superficial microhardness

Objective: This investigation evaluated polymerization shrinkage and depth of cure of five packable composites. Method and materials: Five materials were used for the investigation: Alert, Surefil, Solitaire, P60, and Prodigy Condensable. Groups of 10 specimens of each material were made measuring either 2 or 5 mm in thickness, mounted in a testing jig, and polymerized using a dental curing light. Linear shrinkage was recorded and converted to a volumetric value. To evaluate depth of cure, ten specimens of each material were fabricated in both 2- and 5-mm thicknesses, and a Knoop hardness number was recorded on the top and bottom surfaces 5 minutes after light curing. A one-way analysis of variance statistical test was used to determine if there was a significant difference among materials. A Tukey multiple comparison test was then used to determine where significant differences existed. Results: The volumetric shrinkage for the 2-mm-thick specimens from highest shrinkage to lowest were: Solitaire (3.3%), Prodigy Condensable (1.8%), Surefil (1.4%), P60 (1.2%), and Alert (0.2%). The 5-mm-thick specimens were ranked as follows: Solitaire (2.1%), Prodigy Condensable (1.0%), P60 (0.9%), Surefil (0.8%), and Alert (0.3%). Hardness for the bottom surface of the 2-mm-thick specimens showed that P60 (48.5) and Alert (42.6) had the highest values. Solitaire (11.2) had a significantly lower value. Hardness for the bottom surface at 5-mm thickness showed Alert (16.5) and P60 (16.3) with higher values than Surefil (8.9). Conclusion: Solitaire had the most shrinkage and Alert the least at both 2- and 5-mm depths. Depth of cure was severely compromised for all materials at 5 mm. Keywords: composite, depth of cure, packable composites, shrinkage

Objective: The esthetic application of bleaching materials has gained popularity, with consequences for teeth and restorative materials. The aim of this investigation was to evaluate the influence of different bleaching agents with varying peroxide concentrations on restorative materials. Method and materials: The color behavior, Vickers hardness, and surface roughness were determined on different restorative materials and bovine enamel. Cylindric samples of two fine hybrid composites, one microfilled composite, one compomer, and one ormocer were bleached for two 2-hour periods with three commercial and three experimental bleaching agents with varying peroxide concentrations. The properties were determined before and after bleaching. As a control, all materials were investigated without bleaching after a 14-day storage. Results: The restorative materials showed maximum changes in Vickers hardness of 44, maximum changes in surface roughness of between 0.2 and 0.7 µm, and a maximum discoloration of ΔE = 6.8. A statistically significant deterioration of hardness, combined with the highest discoloration, was found for the microfilled composite and the compomer. Different bleaching systems showed varying effects on surface roughness. Conclusion: Bleaching resulted in a deterioration of the restorative materials, indicated by a decrease of hardness and an increase in surface roughness. Generally, bovine enamel showed significantly higher discoloration compared to the restorative materials. Keywords: CIE-L*a*b* measurement, color behavior, in vitro bleaching, restorative materials

Objective: The objective of this study was to evaluate the clinical performance of two packable and one microhybrid resin composites placed in occlusal cavities of posterior permanent teeth after 1 year. Method and materials: Sixty occlusal restorations were placed in 18 male or female patients aged 21 to 44 years. The restorations were divided into three groups according to the restorative material: G1 (Surefil + Prime&Bond NT); G2 (Filtek P60 + Singlebond), and G3 (Suprafill + Suprafill). They were placed by two previously calibrated operators. The restorations were directly evaluated for color matching, marginal discoloration, secondary caries, wear, marginal adaptation, and postoperative sensitivity. Results: Of the total restorations, 66.7% were scored A (ideal) for color matching; 98.2% for marginal discoloration; 100% for secondary caries; 92.6% for wear; and 92.6% for marginal adaptation. Postoperative sensitivity was reported in 5% of the restorations. Fisher's exact, McNamara's, and chi-square tests did not indicate statistical difference between the groups, related to the evaluated criteria. Conclusions: The packable (Filtek P60 and Surefil) and the microhybrid (Suprafill) resin composites exhibited excellent clinical performance after 1 year and may be considered possible materials for the restoration of posterior teeth. Keywords: Class I restoration, clinical evaluation, color, dental caries, dental restoration, dentinal sensitivity, marginal adaptation, resin composite, tooth discoloration, wear

Objectives: Resin-reinforced glass-ionomer cements were developed by adding resin components to conventional glass-ionomer cement. This improved physical properties and bonding characteristics. FujiCEM is the first paste-paste-type resin-modified glass-ionomer luting cement that enables consistent mixture. The purpose of this study was to evaluate the short-term clinical performance of FujiCEM, which was used for final cementation of indirect restorations, such as inlays, crowns, and fixed partial dentures. Method and materials: A total of 290 restorations (165 crowns, 71 inlays, 15 onlays, 36 fixed partial dentures, 3 implant superstructures) were placed in 268 patients (137 males, 131 females) with a mean age of 54.4 ± 13.0 years. Restorations were luted with FujiCEM mixed for 10 seconds after the teeth surfaces were treated with a conditioner containing 10% citric acid and 2% ferric chloride for 20 seconds, washed, and dried with gentle air flow. Out of the investigated 337 teeth, 99 (29%) teeth were vital, and 238 (71%) were nonvital. These restorations were followed up for a period of 21 months. All the restorations were evaluated for postoperative sensitivity, secondary caries, gingival condition, and pocket depth. Results: No clinical failures (eg, dislodgment, secondary caries, irritation of soft tissue, and postoperative sensitivity) were observed. Conclusion: FujiCEM had promising clinical performance with inlays, crowns, onlays, fixed partial dentures, and implant superstructures at 21 months after service. Keywords: clinical performance, dental material, glass ionomer, luting cement, resin-modified glass-ionomer cement, survival rate

Objective: The aim of this investigation was to evaluate the role of various signs and symptoms of temporomandibular disorders (TMD), among other potential risk factors, in developing frequent headache in a population-based sample of the cross-sectional epidemiologic Study of Health in Pomerania (SHIP). The impact of headache and of myogenous and arthrogenous signs of TMD on the quality of life of this sample was evaluated. Method and materials: Medical history and dental and sociodemographic parameters of 4,255 subjects were checked for correlations with frequent headache using a multivariate logistic regression model. The quality of life of the headache sufferers was evaluated with a questionnaire on mental and physical health. Results: Of the sample, 9% reported suffering from frequent headache. Significant values for the odds ratios for the whole sample were found for pain on palpation of the masticatory muscles; the anamnestic question on masticatory muscle pain; ear noises; lateral palpation pain of the temporomandibular joints (TMJ); several sleep disorders; psychosomatic complaints; and risk for women. Palpation pain of the muscles showed a dose/response effect. Subjects with a higher education level had a significantly reduced risk for developing frequent headache. Anamnestic questions for pain in the TMJ area, TMJ clicking, smoking, alcohol abuse, contraceptives, income, and chronic diseases did not correlate significantly with frequent headache. Subjects who reported frequent headache exhibited a significant reduction of physical and mental health scores. Pain upon muscle palpation showed significantly reduced scores on both scales for both genders. Conclusion: Within the limitations of this study, in addition to sensitive TMJs, mainly palpation-sensitive masticatory muscles showed a significant relation to the occurrence of frequent headache. Because of the number of tested covariates originally included in the model, this relation seems essential. Keywords: epidemiology, headache, quality of life, temporomandibular disorders

Objective: The aim of this study was to evaluate the efficiency of Ultraspeed, Ektaspeed Plus, and Insight radiographic films, and radiovisiography in detecting approximal carious lesions. Method and materials: Eighty approximal surfaces of 40 extracted human molars and premolars were evaluated. Radiographs of teeth blocks were taken with three different films and radiovisiography under standard conditions. The presence or absence of approximal caries was evaluated by three observers according to a five-point confidence scale. The actual status of each surface of the teeth was histologically determined from the teeth sections. Sensitivity, specificity, positive and negative predictive values, and likelihood ratios of the imaging modalities were calculated, and observer responses were assessed with Kendall's tau and Spearman's rho tests. Results: The sensitivity values for Ultraspeed, Ektaspeed Plus, Insight, and radiovisiography were 0.39, 0.48, 0.45, and 0.49, respectively, while the specificity values were 0.91, 0.88, 0.84, and 0.90, respectively. The difference in detecting approximal carious lesions between the systems was not statistically significant. Conclusion: This study suggests that there is no significant difference between the four imaging modalities in detecting approximal carious lesions. Keywords: approximal caries, D-, E-, and F-speed films, radiovisiography

This article reports a case of root dilaceration and enamel hypoplasia in permanent maxillary incisors resulting from acute trauma in the primary dentition and the multidisciplinary treatment provided during 11 years of follow-up. Keywords: dental enamel hypoplasia, tooth abnormalities, tooth injuries, tooth-root injuries