Influence of Different Repair Acrylic Resin and Thermocycling on the Flexural Strength of Denture Base Resin.

Background and Objectives: Fractured acrylic denture base is a common occurrence in clinical practice. The effective denture repair procedure is cost-effective, time conserving, and results in lesser time without denture for the patient. Along with various reinforcements and surface modifications; different acrylic resins are investigated in improving the flexural strength of the fractured site. The aim of this study was to evaluate the flexural strength of a polymethyl methacrylate (PMMA) denture base repaired with heat-polymerized (HPA), auto-polymerized (APA) and light-polymerized acrylic (LPA) resins after thermocycling. Materials and Methods: Forty rectangular shaped (50 mm × 25 mm × 3mm) PMMA specimens were fabricated. Group 1 specimens (n = 10) were kept as controls and the remaining 30 samples were sectioned at the center with a repair site dimension of 3 mm. The samples from three groups (n = 10) were repaired with HPA, APA, and LPA resins, respectively. The specimens were thermocycled for 5000 cycles and subjected to a three-point flexural test. The maximum load required to fracture the specimens was recorded, and further analyzed with ANOVA and the Games-Howell Post hoc test at the significance level p = 0.05. Results: The average maximum load and flexural strength of the control group was 173.60 N and 13.02 Mpa and corresponding values for denture repaired with HPA was 87.36 N and 6.55 Mpa. The corresponding values for APA resin and LPA resins were 62.94 N, 57.51 N, and 4.72 Mpa, 4.06 Mpa, respectively. Conclusions: The PMMA specimens repaired with HPA resins resulted in a significantly higher load to fracture compared to APA resin and LPA resin.

Complete denture fracture - A proposed classification system and its incidence in National Capital Region population: A survey.

AIM: The complete denture fracture of denture may ruin the routine life of an edentulous patient. The aim of the present study was to propose and evaluate a new classification system for denture fractures. SETTINGS AND DESIGN: Cross sectional -Survey. MATERIALS AND METHODS: Ten dental laboratories in Delhi and the National Capital Region participated in the study for 2 years. The accurate assessment of fractured dentures received in the laboratories for repairs was done. A questionnaire with complete information along with photographs was used to classify the denture fracture. STATISTICAL ANALYSIS USED: Percentage (proportion) statistical test. RESULTS: Out of 620 dentures, 164 (94 maxillary and 70 mandibular) were found with previous repair, soft liners, metal frame, or wire reinforcements which were excluded from the study. In the present study, 456 dentures were considered (256 maxillary and 200 mandibular). Class I fracture (midline) was the most common in both maxillary and mandibular dentures (46.87% in maxillary and 61% in mandibular) with high significance (P < 0.001). Class II and Class V were the second most common pattern of fracture in mandibular and maxillary dentures, respectively. There was no single case of Class III fracture for the mandibular dentures, and Class IV was the least common among the maxillary dentures. CONCLUSIONS: This study encourages further clinical studies for validation and reliability evaluation of proposed new classification system.

The Treatment Perspective of Pediatric Condyle Fractures and Long-Term Outcomes.

PURPOSE: In our study, the characteristics, treatment approach and long-term outcomes of condyle fractures treated in the pediatric plastic surgery and reconstruction unit in the last 10 years were evaluated. MATERIALS AND METHODS: This study consisted of two retrospective and prospective sections with the participation of pediatric patients with condylar fractures who were treated in the Plastic, Reconstructive and Aesthetic Surgery clinic of a university hospital in the last 10 years. In the retrospective section, data were obtained from the electronic patient records and patient files regarding the treatment applied, as well as the characteristics of the patient and condyle fractures. In the perspective section, patients were invited to the clinic and the effectiveness of the treatment was evaluated. Statistical analyses were performed with SPSS (Statistical Package for Social Sciences) for IBM 25 package program. RESULTS: It was determined that 55.8% of the pediatric patients had accompanying facial fractures, and 72.4% had unilateral condyle fractures. It was determined that 59.5% of the pediatric patients underwent intermaxillary fixation (IMF). Physical complications were seen in 6.75% in the long term after treatment. CONCLUSION: Falling from height and traffic accidents, which are the most important factors in the occurrence of condyle fractures, should be eliminated by increasing parental attention and awareness. Surgical treatment should be considered in the treatment of pediatric condyle fractures, especially if there are accompanying facial and mandible bone fractures.

Assessment of Cases of Complete Denture Fracture.

BACKGROUND: There are many causes and reasons associated with fractures of complete dentures. The present study assessed case of complete denture fracture. MATERIALS AND METHODS: One hundred and fifty complete denture wearers reported to the department of prosthodontics for correction of complete denture fracture were examined carefully. The factors such as retention, stability, and occlusal errors were recorded. Cause of denture fracture was recorded too. RESULTS: Out of 150 patients, males were 80 and females were 70. The site of fracture was incisor area in 25, canine area in 30, midline in 50, molar area in 10, and maxillary tuberosity/retromolar pad area in 35 cases. The etiology of denture fracture was accidental fall in 42, poor fit in 28, poor occlusion in 40, material breakage in 25, and acrylic base defect in 15 cases. The difference was statistically significant (P < 0.05). CONCLUSION: Most common cause of denture fracture was accidental fall, poor fit, poor occlusion, and material breakage.

The Effect of Joint Surface Preparations and Chemical Surface Treatment on the Transverse Strength of Repaired Denture Base Resin.

AIM: The aim of the study is to investigate the effect of joint surface preparations and chemical surface treatment given to prepared surface on the transverse strength of repaired denture base resin. METHODOLOGY: Two hundred and twenty specimens (DPI India) were randomly allocated into eight groups (n = 10), according to the combination of joint surface preparation (Butt joint, 45° bevel, and rounded joint) and chemical surface treatment (methylene chloride, ethyl acetate, and methyl methacrylate) for 30 and 60 s each. Specimens, after surface treatment, were repaired with self-cured resin (DPI India) and then subjected to 3-point bending test to measure transverse strength. Fractured surfaces were viewed under stereomicroscope and subjected to AutoCAD analysis to determine type of failure (adhesive or cohesive) and measure their area. Measurement data were analyzed by one-way analysis of variance, paired t-test, Dunnett's D test, and multiple comparison Bonferroni t-test, with a 5% significance level. RESULTS: Most of the comparisons between the test specimens were statistically significant. Specimens (methylene chloride for 60 s and rounded joint) show 60%-70% gain of strength. CONCLUSIONS: For providing better bond strength to a repaired specimen, the segment of fractured specimens to be provided "Rounded joint" preparation with etching by methylene chloride for 60 s.

The effect of joint surface contours and glass fiber reinforcement on the transverse strength of repaired acrylic resin: An in vitro study.

BACKGROUND: Denture fracture is an unresolved problem in complete denture prosthodontics. However, the repaired denture often experiences a refracture at the repaired site due to poor transverse strength. Hence, this study was conducted to evaluate the effect of joint surface contours and glass fiber reinforcement on the transverse strength of repaired acrylic resins. MATERIALS AND METHODS: A total of 135 specimens of heat polymerized polymethyl methacrylate resin of dimensions 64 × 10 × 2.5 mm were fabricated. Fifteen intact specimens served as the control and 120 test specimens were divided into four groups (30 specimens each), depending upon the joint surface contour (butt, bevel, rabbet and round), with two subgroups based on type of the repair. Half of the specimens were repaired with plain repair resin and the other half with glass fibers reinforced repair resin. Transverse strength of the specimens was determined using three-point bending test. The results were analyzed using one-way ANOVA and Tukey post-hoc test (α= 0.05). RESULTS: Transverse strength values for all repaired groups were significantly lower than those for the control group (P < 0.001) (88.77 MPa), with exception of round surface design repaired with glass fiber reinforced repair resin (89.92 MPa) which was significantly superior to the other joint surface contours (P < 0.001). Glass fiber reinforced resin significantly improved the repaired denture base resins as compared to the plain repair resin (P < 0.001). CONCLUSION: Specimens repaired with glass fiber reinforced resin and round surface design exhibited highest transverse strength; hence, it can be advocated for repair of denture base resins.

Flexural strength of acrylic resin repairs processed by different methods: water bath, microwave energy and chemical polymerization

Denture fractures are common in daily practice, causing inconvenience to the patient and to the dentists. Denture repairs should have adequate strength, dimensional stability and color match, and should be easily and quickly performed as well as relatively inexpensive. OBJECTIVE: The aim of this study was to evaluate the flexural strength of acrylic resin repairs processed by different methods: warm water-bath, microwave energy, and chemical polymerization. MATERIAL AND METHODS: Sixty rectangular specimens (31x10x2.5 mm) were made with warm water-bath acrylic resin (Lucitone 550) and grouped (15 specimens per group) according to the resin type used to make repair procedure: 1) specimens of warm water-bath resin (Lucitone 550) without repair (control group); 2) specimens of warm water-bath resin repaired with warm water-bath; 3) specimens of warm water-bath resin repaired with microwave resin (Acron MC); 4) specimens of warm water-bath resin repaired with autopolymerized acrylic resin (Simplex). Flexural strength was measured with the three-point bending in a universal testing machine (MTS 810 Material Test System) with load cell of 100 kgf under constant speed of 5 mm/min. Data were analyzed statistically by Kruskal-Wallis test (p<0.05). RESULTS: The control group showed the best result (156.04±1.82 MPa). Significant differences were found among repaired specimens and the results were decreasing as follows: group 3 (43.02±2.25 MPa), group 2 (36.21±1.20 MPa) and group 4 (6.74±0.85 MPa). CONCLUSION: All repaired specimens demonstrated lower flexural strength than the control group. Repairs with autopolymerized acrylic resin showed the lowest flexural strength.