Removal Of Sound Tooth Structure Research Articles

Comparative Effect of two Types of Surface Treatments on Shear Bond Strength of New Composite to Old Composite.

Statement of the Problem: Composite restoration failures may occur because of different factors. In these situations, the repair of a composite restoration has many advantages over replacement such as saving time, lower cost, and lower risk of excessive removal of sound tooth structure and subsequent pulp exposure.Purpose: The purpose of this in vitro study was to evaluate the effects of two surface treatments on shear bond strength (SBS) of new composite to old composite.Materials and Method: In this in vitro study, 60 composite discs were fabricated using a plexiglass mold measuring 4 mm in thickness and 7 mm in diameter, and were randomly divided into three groups (n=20). In group 1, the bonding procedure was done with no modification. After roughening of one surface in all remaining samples, chloroform (CHCl3) was applied on the surface of samples in group 2 and phosphoric acid 35% was applied on the surface of the samples in group 3. PermaSeal was then applied in all samples and new composites were bonded to the surface. The samples were stored in distilled water for one week and were then subjected to 500 thermal cycles and shear bond strength between two layers of composite and mode of failures were evaluated.Results: The lowest and the highest SBS values of repair composite to old composite were noted in groups 3 and 1, respectively and this difference was statistically significant (p< 0.05).The difference between groups 1 and 2 was not significantly different (p= 0.197). The mode of failure was mixed in all samples of groups 2 and 3 and cohesive in group 1.Conclusion: After grinding, the surface treatment with phosphoric acid did not increase the SBS of new composite to old composite, while chloroform increased the SBS almost to the level of the baseline in control group.

Comparative evaluation of the efficiency of caries removal using various minimally invasive techniques with conventional rotary instruments using cone beam computed tomography: An in vitro study

Aim: The aim of this in vitro investigation was to assess the most efficient minimally invasive technique (MIT) by comparing the change in volume after caries removal using cone beam computed tomography (CBCT) and the time taken for each technique. Materials and Methods: Forty human extracted molars, stored in 0.1% thymol solution, with carious lesions extending into the dentin were used in the study. The caries status of dentin was judged initially by visual inspection and probing and confirmed by caries detector dye. A pre-scan CBCT was performed before assessing the volume of the carious lesion. Teeth were assigned into four groups (n = 10): Group 1 = Carisolv gel, Group 2 = Carie Care, Group 3 = ultrasonic tips, and Group 4 = slow-speed rotary instruments. The caries removal was performed according to the manufacturer’s instructions. Time taken was recorded for each method. A postoperative scan was conducted, and volumetric analysis was carried out. The amount of removal of sound tooth structure was assessed to determine the most MIT. Descriptive and inferential statistics were used to analyze the data. The intergroup volume change of caries was carried out using the Kruskal–Wallis test, whereas comparison within the group was carried out using Wilcoxon signed-rank test. The assessment of time taken during each procedure was analyzed with one-way analysis of variance and Tukey honest significant difference test. The results were tabulated accordingly. Significance was set at P value ≤ 0.05. Results: The chemomechanical agents (Carisolv and Carie Care) showed minimal change in volume when compared to conventional diamond points. The time taken with conventional diamond point was minimum, and it was maximum for ultrasonic tips. Conclusion: Chemomechanical caries removal is the most minimalistic approach when compared to the other techniques.

Effect of two desensitizing agents on crown retention using zinc phosphate cement

Introduction: Preparation of vital teeth involves removal of sound tooth structure, which causes opening of dentinal tubules, thereby causing displacement of the dentinal tubular fluid, leading to dentinal hypersensitivity. After cementation of crowns in such teeth, incidence of pain and hypersensitivity has been reported. An extensive use of desensitizing agents has been observed over the past few decades because of the introduction of newer agents and the increased incidence of post-cementation sensitivity. Dentin desensitizing agents are commonly used in dental practice. But their effects on crown retention have been anecdotal. Materials and Methods: Thirty-three extracted human maxillary first premolar teeth were selected for the study, which were prepared using a special assembly and divided into three groups (i.e., ZP + U, ZP + G, and ZP) to compare the effect of Gluma (Heraeus-Kulzer, Germany) and Ultraseal (Ultradent, USA) on crown retention using zinc phosphate cement. Results: It was seen that the group ZP + G was statistically significant with groups ZP and ZP + U. However, no such difference was observed between ZP and ZP + U. Conclusion: Both the agents can be used and prove effective when used with zinc phosphate cement. However, the major mode of failure was adhesive in nature with the cement being retained on both the crown and the tooth structure.

Intrusion of Overerupted Molars by Corticotomy and Fixed Orthodontic Appliances

ABSTRACTIn this article, a review of the literature regarding the use of selective alveolar corticotomies (SAC) combined with orthodontic treatment was conducted, and the results of its use in a patient with overerupted maxillary 1st molars are described. Adequate intrusion was obtained within a short period of time, the protocol avoided the necessity of removal of sound tooth structure for crown lengthening, endodontic treatment, and full crown prosthetic restorations. Therefore, the obtained results indicate that SAC/orthodontic use is efficient in the intrusion of overerupted 1st molars and suggest its potential use in the treatment of other malocclusions.How to cite this articlede Souza MLAH, Soares RV, Zenóbio EG, Pithon MM, Oliveira DD. Intrusion of Overerupted Molars by Corticotomy and Fixed Orthodontic Appliances. Int J Experiment Dent Sci 2016;5(1):78-82.

Comparison of mechanical and chemomechanical methods of caries removal in deciduous and permanent teeth: A SEM study

Mechanical method of caries removal is associated with the removal of sound tooth structure, production of pain, heat, annoying sounds, and vibrations. Chemomechanical caries removal method is based on removal of only carious dentin leaving sound dentin intact. The aim of this study was to compare the efficacy of mechanical and chemomechanical methods of caries removal in deciduous and permanent teeth. A total of 30 carious teeth including 15 deciduous and 15 permanent teeth having dentinal caries selected randomly and cut into two halves through center of the lesion, were subjected to caries removal by mechanical (Group A), and chemomechanical methods (Group B). Time taken for removal of caries was noted with stopwatch. Samples were prepared and seen under the scanning electron microscope for the presence of bacterial colonies. Data were analyzed using statistical package for social sciences (SPSS) Software. No significant difference was found for the presence of bacterial colonies in both groups of deciduous and permanent teeth; however, time taken for caries removal by the chemomechanical method was twice than the mechanical method. despite the insignificant presence of bacterial colonies and twice time taken as compared to mechanical method, chemomechanical method was easy to introduce, was painless, did not form smear layer and conserved the sound tooth structure.

Revisiting Amalgam: A Comparative Study between Bonded Amalgam Restoration and Amalgam Retained with Undercuts

To compare the retention of amalgam restorations in bonded amalgam restoration and restorations with undercuts. With improvement in adhesive technology problem associated with conventional preparation for amalgam restorations mainly compromised resistance form of tooth structure have been largely overcome. Forty caries free extracted molars were used. A basic box preparation was done proximally with buccoproximal and linguoproximal walls diverging at 45° angle and the axial wall is 1.3 mm in dentin. The teeth were randomly divided into 4 groups of 10 each. Group 1 - Teeth with basic box preparation. Group 2 - Teeth with box preparation for bonded amalgam. Group 3 - Teeth with box preparation and proximal retention grooves. Group 4 - Teeth with box preparation and occlusal dovetail. Group 1, 3 and 4 were restored with silver amalgam and group 2 restored with resin-bonded amalgam. All samples were subjected to simulated occlusal load against marginal ridge using a blunt stainless steel point in an Instron testing machine. The force in kilogram required to dislodge the restorations as well as the type and location of failure were recorded. The main force required to dislodge the restoration was least in group 1 and 3 and maximum in group 2. The in vitro study showed that the amalgam bonding technique, using an adhesive resin liner in proximal box form preparation, was more effective than either box form with proximal grooves or dovetails or proximal box only in providing resistance to displacement. Amalgam bonding eliminates the unnecessary removal of sound tooth structure during cavity preparations.

A BITTERSWEET SILVER ANNIVERSARY FOR THE BONDED PORCELAIN VENEER RESTORATION

A BITTERSWEET SILVER ANNIVERSARY FOR THE BONDED PORCELAIN VENEER RESTORATION

The influence of the cavity preparation design on marginal accuracy of laboratory-processed resin composite restorations

The aim of this study was to evaluate the influence of different cavity preparation designs on marginal accuracy of laboratory-processed resin composite restored teeth. Eighty mandibular human third molars were selected. There were two experimental factors, occlusal isthmus width (narrow vs wide) and cuspal coverage (inlay, one-cusp onlay, two-cusp onlay, and all-cusp onlay), resulting on eight groups (N = 10). Indirect composite restorations (SR Adoro, Ivoclar-Vivadent) were manufactured and positioned over each respective preparation. Marginal accuracy evaluation was accomplished using a stereomicroscope at three points on buccal, lingual, mesial, and distal regions with 40x magnification. The results showed significant differences (P = 0.00) with wide inlay showing the best overall marginal accuracy and narrow inlay the worst one. Two-way analysis of variance (ANOVA) showed significant differences when considering the factor occlusal isthmus width (P = 0.00). In general, preparations with wide occlusal isthmus presented better results than narrow ones, except for wide all-cusp onlays; however, the test failed to show differences when considering the cuspal coverage (P = 0.42) or the interaction between both factors (P = 0.30). The effect of occlusal width extension on marginal accuracy of indirect composite resin restorations is significant, with lower values of gaps width in wide preparations, but since in a clinical situation this would mean greater removal of sound tooth structure, less-aggressive preparations combined with other restorative procedures seem to be more feasible.

A Chemomechanical Method for Caries Removal

Over recent years the dental profession has shifted towards practising preventive dentistry and adopting more conservative and tooth-preserving procedures. Such progression is considered to be a response to the decline in the level of dental caries and advances in materials science. This shift in caries management will no doubt continue over the coming decades, based on rational clinical and scientific principles. Chemomechanical caries removal involves the application of a solution that selectively softens the carious dentine, thus facilitating its removal. This limits the removal of sound tooth structure, the cutting of open dentinal tubules, pulpal irritation and pain compared with conventional mechanical methods.

Pronase Digestion of Carious Dentin

The aim of this study was to investigate the individual capabilities of the proteolytic enzyme preparation Pronase™, the enzyme collagenase and sodium hypochlorite to disintegrate and solubilize carious dentin. Samples of carious dentin, and samples of sound dentin for comparison, were extracted 4 times in succession for 24 h with buffered solutions of Pronase. Separate carious dentin samples were extracted in the same manner with buffered solutions of collagenase or with aqueous sodium hypochlorite. The extracts, the solid residues left over after the extractions and untreated samples of carious and sound dentin were digested with sulfuric acid–H₂O₂ and then analyzed for nitrogen content by a special adaptation of the Berthelot color reaction. Although Pronase did not attack sound dentin, it solubilized more than 90% of the nitrogen present in carious dentin. Collagenase solubilized approximately 66% of the nitrogen, whereas sodium hypochlorite released only 12–20% of the nitrogen of carious dentin. In clinical dentistry, chemical disintegration of carious dentin may reduce the need for mechanical removal of sound tooth structure.