Ridge Lap Research Articles

Evaluation Of Silano Adhesive Efficiency in Improvement of Shear Binding Strength of Synthetic Teeth to Thermo-Plastic Denture Material

Background: One of the most serious problems concerning denture performance is the possibility of prosthetic tooth displacement due to increased chewing efficiency. The nature of the mechanical bonding between thermoplastic denture base materials and acrylic teeth has aggravated the problem of tooth debonding. The study aiming to examine the strength of shear bond between prosthetic teeth and thermoplastic base material utilizing silano (silane coupling agent) and mechanical surface modifications (Alumin-ablasting, T. Shape hole) of tooth ridge lap pre and post (100 hrs.) of accelerated ageing conditions. Materials and method: The surface treatments of (120) maxillary central incisors were chosen and grouped into 6 groups of 20 samples each. Each group split into before and after (100hrs.) according to ageing (n=10). Measurement of shear bonding strength applied by a universal testing equipment with 0.5mm/min crosshead speed. Statistical analyses were done using one-way ANOVA test and Tukey’s (HSD) test. Results: Statistics showed high significant variation in average binding force after several surface manipulations in contrast to the control group at (P < 0.000). Regarding surface manipulations, dual treatment of “Alumina-blasting + silano “revealed significant elevation of binding strength in compare to “alumina-blasting” alone (P < 0.001). Similarly, with “T. hole + silano” yielded in greatly increased bonding strength compared to using “T. hole” alone (P < 0.001). a great reduction in bonding strength value was indicated along all treated groups after ageing process (P < 0.000) except the group treated with “T. Hole + silano” show non-significant variations at (p = 0.112). Conclusion: combination treatment (chemo-mechanically) with “T. Hole + silano” improve shear binding strength and not effected with ageing process.

Case Report: Rehabilitation of anterior esthetic region with ovate pontic

The period of time between extraction and recovery following tooth loss in the esthetic zone can be awful to the patient's appearance and mental health. A suitable alternative to extraction and replacement of a maxillary anterior tooth is quick tooth replacement with an ovate pontic on a temporary fixed partial denture. The interdental papilla, which is preserved by ovate pontic, in turn protects the contour of gingiva that after extraction would have been lost. Utilizing an ovate pontic, an instantaneous tooth replacement removes the emotionally distressing partial edentulous stage, while also producing a considerably more aesthetically acceptable, hygienic, and natural-looking replacement tooth. Ovate pontics have the additional benefit of avoiding the dissatisfaction associated with an unattractive ridge lap pontic. The case study demonstrated an ovate pontic replacement for an upper anterior tooth that helped a patient whose mobile anterior tooth was advised for extraction and finally resulting to both improved esthetics and health.

Evaluation of Load-bearing Capacity of Interim Fixed Partial Dentures Reinforced with Glass Fibers: An In Vitro Study.

To compare the load-bearing capacity of three and four-unit fixed partial denture (FPD) with two different designs of pontics reinforced with industrial glass fibers at two different positions of the FPD. A total of 64 samples were made with Bis-acryl composite temporary material and reinforced with industrial glass fibers (E-glass). The specimens were divided into eight groups (groups I-VIII) depending on the number of units, type of pontic design and area of placement of fibers. A universal testing machine was used to evaluate and compare the load-bearing capacity of the specimens. The evaluated data were statistically analyzed using one-way ANOVA and Bonferroni post hoc tests (p ≤ 0.05). Three-unit interim FPD and modified ridge lap pontic design showed greater load-bearing capacity after reinforcement with glass fibers than a four-unit interim FPD and hygienic pontic design, respectively. Fiber placement at the occlusal plus connector area as well as the cervical plus connector area had comparable results. Industrial glass fibers (E-glass) could be used as a cheaper alternative but clinical performance and their safety are yet to be evaluated. Reinforcement with industrial-grade glass fibers can be a cheaper option for increasing the load-bearing capacity of interim partial dentures, but it needs to be studied in vivo through further studies.

Effect of Different Chemical Surface Treatments on the Shear Bond Strength of Acrylic Teeth With Different High-Impact Denture Base Resins.

Introduction The debonding of acrylic teeth from the denture base, particularly in cases of prominent ridges, is a common problem faced by clinicians and patients. The present study was conducted to assess the effects of various chemical treatments on the shear bond strength (SBS) of acrylic teeth bonded to different high-impact denture base materials. Materials and methods The present in vitro study was conducted on 80 wax specimens with acrylic teeth bonded to two high-impact denture base materials (DPI Tuff (DPI Dental Products of India Ltd, Mumbai) and Trevalon HI (Trevalon HI, Dentsply, Karnataka)). The two main groups were further divided into four subgroups of 10 specimens each, depending on the chemical treatment at the ridge lap area of the tooth: control group without any chemical treatment, chemical surface treatment (CST) with dichloromethane and monomer mix, CST with ethyl acetate, and CST with acrylic adhesive cyanoacrylate. The SBS was tested using a universal testing machine (UTM). Analysis of variance (ANOVA) and post-hoc Tukey tests were used for statistical analyses. Results The mean SBS of Group A (DPI Tuff) was 111.75 Nas compared to 118 N in Group B (Trevalon HI). The differences were statistically significant (p<0.05). ANOVA and post-hoc Tukey's tests revealed significant differences between subgroups. The highest mean SBS was noted with a dichloromethane and monomer mix (1:1 volume), followed by the ethyl acetate, control, and cyanoacrylate subgroups. Conclusion The cross-linked acrylic teeth treated with a dichloromethane and monomer mixture (1:1 by volume), processed with Trevalon HI high-impact denture base resin had the highest SBS and thus were indicated for bonding teeth with the suggested denture base.

Evaluation Of Fusion Liquid Efficiency In Improvement Of Shear Binding Strength Of Synthetic Teeth To Thermo-Plastic Denture Material

Background: Due to increased chewing capability, one of the most common problems with dentures is that prosthetic teeth can come loose from the denture. The mechanical design of the connection between thermoplastic base materials and acrylic teeth has increased the problem of tooth debonding.&#x0D; Objective: The current study was conducted to assess the shear bind strength of artificial teeth to thermoplastic resin utilizing fusing liquid and mechanical modifications (Alumin-ablasting, T. hole) of tooth ridge lap before and after 100 hours of accelerated ageing.&#x0D; Materials and method: A total 120 maxillary central incisors have been chosen and grouped into 6 groups of 20 samples each, according to surface treatments. each group subdivided into before and after 100hrs according to artificial ageing (n=10). Shear bond strength test conducted by a universal measurement apparatus with crosshead speed 0.5mm / min. Data were statistically analyzed by one-way ANOVA and Tukey’s (HSD).&#x0D; &#x0D; Results: Various surface treatments techniques significantly affected the shear bond strength with statistical high difference in mean bond strength after various surface treatments compared to the control group at (p &lt; 0.001). Regarding surface treatment, Dual treatment of “alumina-blasting + fusion liquid” showed considerably elevated strength compared to alumina-blasting alone at (p &lt; 0.001). also “T. hole +fusion liquid” treatment yielded a significant elevation in strength reading compared to T. hole alone at (p &lt; 0.001). Great significant full in strength value was noted in all groups post 100hrs of artificial ageing process at (p &lt; 0.001). The combined surface treatment revealed the lowest percentage reduction in SBS yielded in (T. Hole + fusion), (Alumina-blasting + fusion) than T. hole alone and alumina-blasting alone after 100hrs of artificial ageing process.&#x0D; Conclusion: Surface treatment with T. hole + fusion liquid or alumina-blasting + fusion liquid enhanced SBS.

Shear bond strength between denture teeth and denture base using different bonding resins and tooth surface treatments

Aim of studyThe aim of the present study was to evaluate the influence of surface treatments of the ridge lap area of PMMA acrylic denture teeth on their shear bond strength with different bonding resins to denture base milled from prefabricated PMMA block, in a two-way factorial experiment. The traditional heat-curing method was included as a reference method to compare to the proposed new method that employs digital technology. Materials and methodsFifty-four cylindrical rods were prepared from two different types of PMMA based denture resin; one specially designed for the computer-aided design and computer-aided manufacturing (CAD/CAM) milling method (groups A, n = 18 and B, n = 18) and a conventional heat-curing resin (group C, n = 18). A central maxillary incisor was selected as the experimental tooth. The specimens of each group A, B, and C were divided equally into three subgroups (a, b, c; n = 6 for every subgroup) according to three surface conditionings (no treatment, sandblasting, sandblasting plus methyl-methacrylate application, respectively). A specially designed bonding resin for digital dentures was used in group A, and a common self-curing resin for repairs in group B, while in group C the specimens were prepared by the conventional heat-curing method. Shear bond strength was determined using an electro-mechanic loading frame (MTS Insight) with a cross-head speed to 1 mm/min. ResultsThere was a statistically significant interaction between the construction method (A, B, C) and tooth surface treatment (a, b, c) (p = 0.026). After eliminating one subgroup, the effect of tooth surface treatment was not significant (p = 0.42). ConclusionsSurface treatment seems not to affect the teeth-base bond. Denture teeth bonded to a CAD/CAM denture base using PMMA self-curing resin for repairs (group B) showed the highest bond strength compared to groups A and C. Clinical significanceIn terms of bond strength, the digital denture construction method can be successfully used in everyday clinical and laboratory practice and replace effectively the conventional heat curing method.

Pontic design and its effects on the health of the gingiva

A pontic is an artificial tooth that substitutes a lost natural tooth, preserves its function, and typically fills the space left by the actual crown. Sanitary/hygienic and modified sanitary/hygienic designs do not contact the alveolar mucosa. On the other hand, ridge lap, modified ridge lap, ovate, modified ovate, and conical are designs that maintain contact with the mucosa. The ideal biological properties to be taken into consideration while designing pontics are periodontal health, access for oral hygiene, no food trapping and occlusal harmony. Accumulation of dental plaque has been implicated in the onset of gingival and periodontal disease as well as caries in the vicinity of the fixed restoration. The connection of the pontic to the supporting crowns must be constructed in such a way as to make a flushable area in the direction of the gingiva, in order to ensure that this area can be cleaned by toothbrushing and flossing but not the large triangular spaces that make it easy for food particles to cling. Modified ridge lap and ovate types, out of all the pontic shapes described below, exhibit convex cleansable faces. Ovate pontics are most effective for use in anterior regions, while the modified ridge lap design can be utilized predominantly in fixed partial denture designs posteriorly. The important etiological factor for gingivitis, periodontitis and peri-implantitis is bacterial colonization which is impacted by the individual's immunologic response and genetic predisposition in addition to dental care practices and pontic design. It is believed that no matter what the material of the pontic is, it must provide a highly polished intaglio surface to help floss slide through and make contact with the full base of the pontic in order to minimize plaque accumulation.

Evaluation of shear bond strength of high molecular chitosan nanoparticle incorporated heat polymerized polymethyl methacrylate denture base resin with acrylic resin teeth: An in-vitro study

The present study is conducted to evaluate the shear bond strength of acrylic resin denture teeth to high molecular chitosan nanoparticle incorporated heat polymerized polymethylmethacrylate denture base resin. This comparative study is performed at the Department of Prosthodontics and Crown & Bridge, JSSDCH, Mysuru. 45 samples of acrylic resin blocks of size 8 × 10 × 20 mm were fabricated using mold such that the long axis of crosslinked acrylic resin maxillary central incisor teeth is aligned at 45° to the long side of the specimen to which the ridge lap surface is attached. Among these, 15 samples belong to the control group, 15 samples to the 0.5 % chitosan gel incorporated group, and the remaining 15 samples to the 1 % chitosan gel incorporated group. The test specimens were then subjected to a failure load test using the universal testing machine. The readings were tabulated and statistically analyzed using Mean, Standard deviation, Independent t-test, - way and two-way ANOVA, and Scheffes’ Post hoc test. The statistical analysis reveals that the mean bond strength of acrylic denture teeth to conventional heat cure PMMA denture base material increased from 4.6627 ± 0.54198 MPa to 7.5186 ± 0.57461 MPa and 8.9356 ± 0.63675 MPa upon addition of chitosan at 0.5 % and 1 % concentration, respectively. It can be concluded that The mean shear bond strength of acrylic denture teeth to conventional heat cure PMMA denture base material increased with the addition of chitosan at 0.5 and 1 % concentration. The best shear bond strength was observed with the addition of 1 % chitosan as per the evidence.

Evaluation Of Fusion Liquid Efficiency In Improvement Of Shear Binding Strength Of Synthetic Teeth To Thermo-Plastic Denture Material

Background: Due to increased chewing capability, one of the most common problems with dentures is that prosthetic teeth can come loose from the denture. The mechanical design of the connection between thermoplastic base materials and acrylic teeth has increased the problem of tooth debonding.&#x0D; Objective: The current study was conducted to assess the shear bind strength of artificial teeth to thermoplastic resin utilizing fusing liquid and mechanical modifications (Alumin-ablasting, T. hole) of tooth ridge lap before and after 100 hours of accelerated ageing.&#x0D; Materials and method: A total 120 maxillary central incisors have been chosen and grouped into 6 groups of 20 samples each, according to surface treatments. each group subdivided into before and after 100hrs according to artificial ageing (n=10). Shear bond strength test conducted by a universal measurement apparatus with crosshead speed 0.5mm / min. Data were statistically analyzed by one-way ANOVA and Tukey’s (HSD).&#x0D; &#x0D; Results: Various surface treatments techniques significantly affected the shear bond strength with statistical high difference in mean bond strength after various surface treatments compared to the control group at (p &lt; 0.001). Regarding surface treatment, Dual treatment of “alumina-blasting + fusion liquid” showed considerably elevated strength compared to alumina-blasting alone at (p &lt; 0.001). also “T. hole +fusion liquid” treatment yielded a significant elevation in strength reading compared to T. hole alone at (p &lt; 0.001). Great significant full in strength value was noted in all groups post 100hrs of artificial ageing process at (p &lt; 0.001). The combined surface treatment revealed the lowest percentage reduction in SBS yielded in (T. Hole + fusion), (Alumina-blasting + fusion) than T. hole alone and alumina-blasting alone after 100hrs of artificial ageing process.&#x0D; Conclusion: Surface treatment with T. hole + fusion liquid or alumina-blasting + fusion liquid enhanced SBS.

Evaluating bond strength of acrylic teeth to conventional and high impact denture base resin incorporating various groove designs

Purpose: In spite of chemical union between acrylic resin teeth and acrylic denture base material, detachment of teeth particularly anterior teeth is a frequent observation. The purpose of this study was to evaluate shear bond strength between denture base resin and acrylic resin denture teeth after incorporating various grooves on the ridge lap area. Materials &amp; Methods: A total of 60 samples were prepared and divided into two groups with 30 samples each. Sample in group I were processed with conventional resin whereas in group II with high impact resin. The teeth in each group were subjected to no treatment, vertical groove &amp; Horizontal retentive goove placement on the ridge lap area. In each group unmodified teeth served as control. A shear force was applied at an angle of 130 degrees to the lingual surface of teeth using instron universal testing machine until fracture occurred. Data obtained was statistically analysed using Post hoc and Mann-Whitney Test. Results: Unmodified resin teeth showed the least bond strength. Modification of teeth with vertical and horizontal groove significantly improves the bond strength with denture resin. A significantly greater force was required to fracture teeth from high impact resin and with vertical groove.

Evaluation of ridge lap accuracy and adaptation of the diagnostic tooth arrangement fabricated with CAD-CAM systems: An in vitro study

Statement of problemDigital light processing (DLP) and milling (MIL) are computer-aided design and computer-aided manufacturing (CAD-CAM) systems that have become popular for fabricating definitive complete dentures. However, few studies have compared the accuracy of the ridge laps of diagnostic tooth arrangements fabricated with these systems and their adaptation with the denture base sockets. PurposeThe purpose of this in vitro study was to comparatively analyze the accuracy of the ridge laps of the diagnostic tooth arrangements fabricated by using MIL and different layer thicknesses in DLP. Material and methodsA virtual definitive complete denture was designed with a CAD software program on a scanned virtual digital cast, divided into diagnostic tooth arrangement and a denture base that accommodated the arrangement, and saved as a standard tessellation language (STL) file. From this file, 27 diagnostic tooth arrangements were fabricated by DLP (50 μm and 100 μm) and MIL. The ridge laps were scanned and overlapped on the file (reference data) to analyze the accuracy (trueness and precision). The ridge laps of all groups were overlapped on the reference denture base data to analyze their adaptation with the sockets. The measurements of the trueness, precision, and adaptation were analyzed statistically by using the nonparametric Kruskal-Wallis test and post hoc Mann-Whitney U test with Bonferroni correction. ResultsThe diagnostic tooth arrangements showed significant differences among the groups (P<.001). The values were the lowest in the MIL group and highest in the DLP group for the following parameters: trueness root-mean-square (RMS) value, 173 ±7 μm versus 286 ±15 μm; precision RMS value, 22 ±3 μm versus 57 ±20 μm; and adaptation RMS value, 41 ±5 μm versus 112 ±13 μm. ConclusionsOf the 2 diagnostic tooth arrangements fabricated with the CAD-CAM systems, the one fabricated with MIL was clinically more appropriate.

REHABILITATION OF MASTICATION AND LACK OF SPACE TREATMENT IN NARROW EDENTULOUS WITH FIXED-FIXED BRIDGE

Background: Loss of posterior teeth can lead to disharmony in the curvature of the jaw. Antagonistic teeth and surrounding teeth will migrate to the edentulous causing reduced mastication function and TMJ disturbance. Several cases of narrow edentulous occurred due to tooth shifting caused by edentulous that was left empty for a long period. Creating a fixed-fixed bridge is aimed to restore the aesthetics, function, and comfort for patients which caused by the missing teeth. Fixed-fixed bridge consist of a retainer that function as a support to the abutment; a pontic that function to replace the missing tooth; and a connector that function to connect the pontic and the retainer. A narrow space for pontics can disrupt the aesthetic and functional aspects. Case Report: A 24 year-old male patient was referred to Prosthodontic Clinic, Gusti Hasan Aman Dental Hospital with a complain of pain on the jaw joint and missing of left lower molar for about 5 years. Patient always masticate on one side after the left lower molar was missing. Extraoral examination found the patient to be in good condition, no enlargement of major salivary glands, the vital signs were good, but upon TMJ examination there was clicking sounds on the left side. Intraoral examination showed space narrowing resulted from mesial and distal drifting of 37 and 35 but not significant, therefore it was still possible to perform rehabilitation using fixed-fixed bridge with abutments on 37 and 35 with modification of pontic shape for 36 to resemble a premolar tooth with occlusal surface resembling a molar tooth. Treatment planning for fixed prosthetic using fixed-fixed bridge with porcelain fused to metal material on 35, 36, and 37 with ridge lap pontic type modification Conclusions: Treatment was successful to provide enough space for the pontic by modification of the shape and the size of the pontic. Keywords: Fixed-fixed bridge. lack of space, mastication.

Effect of mechanical and chemical surface treatment on bond strength of acrylic denture teeth to heat cure acrylic resin-an invitro study

Debonding of denture teeth from the denture base has posed a great problem to the clinician and patient. Chemical and mechanical treatments have been performed separately, but there are no studies performed using the combination of chemical and mechanical surface treatments. This study aims at evaluating and comparing the bond strength by using chemical and mechanical surface treatments.60 maxillary right central incisor teeth were used in 5 groups for surface treatment on the ridge lap area: 1 untreated, 2-sandblasting, group 3- Heat cure monomer, 4- sandblasting+ monomer, 5- Dichloromethane. The acrylic teeth were attached to a wax block at an angle of 45º. These were flasked and dewaxed, followed by surface treatment and acrylisation. All cured specimens were loaded under a universal testing machine on the palatal surface at a cross head speed of 1mm/min till fracture occurred. Data obtained was statistically evaluated by one way ANOVA. Surface treatment with dichloromethane showed the highest bond strength of acrylic teeth to heat cure denture base when compared with sandblasting and monomer application. On visual analysis of the fractured specimens, maximum amount of cohesive failures were noticed in the dichloromethane group.Dicholoromethane can be used as an effective and quick method to improve the bonding of acrylic teeth to denture base.

Efficacy of Natural Tooth Pontic in Periodontally Compromised Patients: A Systematic Review

Periodontitis is a major concern for the dentist because the destruction of periodontal fibers causes mobility of teeth and eventually leads to tooth loss. Conventional techniques like removable temporary acrylic prosthesis, or resin-bonded bridges hold their own disadvantages and a fixed prosthesis may worsen the existing condition. Natural tooth pontic (NTP) in such cases may be advantageous in terms of esthetics and patient satisfaction along with cost effectiveness. Hence, the aim of this review was to evaluate the efficacy of NTP in periodontally compromised patients. Electronic search on data sources such as PubMed and Google scholar along with hand searching of the articles was done in institutional library. All case reports and case series were included in English language published till October 31, 2019, were included. After applying inclusion and exclusion criteria, ten articles were selected for the present review. The whole process was conducted by following the Preferred Reporting Items for Systematic Reviews guidelines. Our review noted that all the patients were satisfied with the appearance of the tooth and also comfortable in maintaining the oral hygiene as these pontics had a ridge lap design. Survival rate was 100% except for the case series which reported a survival rate of 75% while few others did not report anything since no follow-up was conducted. Overall NTP was well accepted by the patients. NTP can be of a great option as prosthesis in the patients with compromised periodontium. Patient's positive satisfaction, cost viability, and accomplishment of appearance in the esthetic zone of the oral cavity make this strategy as a valuable treatment option.

Comparative evaluation of bond strength of denture base resin to acrylic resin teeth following different surface treatments: An In vitro study

Acrylic resin denture base material has been available to the dental profession for over 60 years, and although materials with superior properties have been on the market for some time, it still remains the most popular choice of clinicians. The requirement of the simple processing equipment and low cost of the fabrication process are the reasons for its continued popularity. However, debonding of acrylic teeth from denture base resins remains a problem for both patients and clinicians. The failure rate of acrylic dentures resulting from fracture has been reported to be unacceptably high, with the most prevalent type of failure documented being debonding or fractures of the teeth A series of studies have attempted to determine the quality of denture tooth bonding produced by commonly employed dental laboratory conditions. The present study was under taken to evaluate and compare the effects of chemical and mechanical treatment of the ridge lap surface of acrylic teeth on the bond strength of acrylic resin teeth to denture base resins.

Bond strength of artificial teeth to thermoplastic denture base resin for injection molding.

This research was conducted to investigate the bond strength between artificial teeth and a thermoplastic denture base resin for injection molding with different surface preparations for use in flexible resin removable partial dentures. Composite resin denture teeth and acrylic denture resin teeth were bonded to three types of thermoplastic denture base resins for injection molding (polyamide, polyester, and polycarbonate) and a conventional heat-polymerized polymethyl methacrylate (PMMA) resin (control). The ridge lap surfaces of the artificial teeth were classified into four groups based on the type of ridge lap surface treatment applied (n=10): no treatment, ethyl acetate, small T-shaped tunnel, and large T-shaped tunnel. The specimens were tested for bond strength. The results showed that the ethyl acetate treatment was ineffective for enhancing the bond strength (p>0.05) between the artificial teeth and thermoplastic denture base resin for injection molding, whereas the T-shaped tunnel was quite effective in this regard (p<0.05).

Evaluation of trueness in a denture base fabricated by using CAD-CAM systems and adaptation to the socketed surface of denture base: An in vitro study

Statement of problemComputer-aided design and computer-aided manufacturing (CAD-CAM) systems are increasingly used to fabricate removable complete dentures. However, comparisons and analyses of the trueness and adaptation of the socketed surface of denture bases produced by milling (MIL) and digital light processing (DLP) are lacking. PurposeThe purpose of this in vitro study was to evaluate and compare the trueness and socketed surface adaptation of denture bases fabricated by using additive and subtractive manufacturing. Material and methodsBased on a denture base standard tessellation language (STL) file, a total of 15 denture bases were produced by using DLP (horizontal and vertical direction) and MIL. The intaglio and cameo surfaces of the fabricated denture bases were scanned with a dental scanner. The scanned intaglio and cameo surfaces were overlapped with the corresponding reference denture base STL file for trueness evaluation. In addition, the ridge lap STL file of the diagnostic tooth arrangement, in which reverse normal was performed, was superimposed on the socketed surface of the denture base of all groups to evaluate adaptation. ResultsThe root mean square (RMS) values of trueness and adaptation showed statistically significant differences (P<.05). For the trueness RMS value of the intaglio surface of the denture base, the MIL-denture base (MDB) group had the lowest value of 150 ±6 μm, whereas the vertical denture base (VDB) of the DLP group was the largest with 328 ±4 μm. For the trueness RMS value of the cameo surface, the MDB group was the lowest with 50 ±1 μm, whereas the VDB group was the largest with 334 ±24 μm. For the adaptation RMS value of the socketed surface of the denture base, the MDB group was the lowest with 44 μm, whereas the VDB group was the largest with 117 ±2 μm. ConclusionsWithin the limits of this in vitro study, the MDB group showed better trueness and socketed surface adaptation than the DLP groups (HDB and VDB).

A Study to Assess the Bond Strength of Acrylic Teeth With Different Retentive Features.

ABSTRACTBackground and Aim:Flexible denture base has been gaining attention as a denture base material because of its toxicological safety, comfort, and enhanced aesthetics. Debonding of acrylic teeth from the flexible denture base material has posed a great problem to the clinician and patient. This study aimed at comparing the bond strength between flexible denture base with acrylic teeth having different mechanical modifications.Materials and Methods:Forty mandibular molar teeth (Combination Acry Rock, Badia Polesine (Ro), Italy) were used in four groups for mechanical modifications on the ridge lap area. The groups were group 1 (no mechanical modifications), group 2 (round groove 2 mm in diameter and 2 mm deep on the ridge lap surface), group 3 (horizontal slot 2 mm deep, 2 mm wide, and 4 mm long prepared on the ridge lap surface of the teeth), and group 4 (T-shaped groove 2 mm deep, 2 mm wide, and length of 4 mm mesiodistally and 2 mm buccolingually prepared with a straight fissure bur). The acrylic teeth were attached to a wax block of dimension 1.2 cm × 1.2 cm × 2.5 cm. These were flasked and dewaxed, followed by injection molding with Valplast flexible denture base material. The bond strength was assessed by attaching the specimens to universal testing machine tested under a tensile load at a cross-head speed of 1 mm/min till it fractured. Data obtained were statistically evaluated by one-way analysis of variance and post hoc test.Results:There was significant increase in mean bond strength after various mechanical modifications. Group with T-shaped diatoric hole showed greatest bond strength value compared to other groups.Conclusion:Incorporating mechanical retentive features with increased surface area and undercut can improve the bonding of acrylic teeth to flexible denture base.

Comparative Evaluation of Bond Strength between Ridge Lap Surface of Acrylic Teeth and Denture Base Resin: An In Vitro Study

Abstract Statement of Problem Acrylic teeth are preferred to porcelain teeth in dentures as they unite chemically with denture base resin, but their fracture from denture is common. Purpose The purpose of this study was to improve the bond strength of denture teeth to acrylic resin denture base by chemical or mechanical modification of the ridge lap surface of denture teeth. Materials and Methods Total 100 artificial cross-linked acrylic resin central incisors were divided into five groups: group A, 20 samples without modification (control group); group B, 20 samples (ridge lap surface of teeth treated with monomer); group C, 20 samples (ridge lap surface of teeth treated with monomer and the glaze layer removed with aluminum oxide abrasive stone); group D, 20 samples (ridge lap surface of teeth treated with dichloromethane); and group E, 20 samples (dichloromethane application followed by abrasion with aluminum oxide stone on ridge lap surface of teeth). They were mounted on wax blocks, and the blocks were acrylized. The bond strength values were obtained by subjecting the samples to shear compressive load under universal testing machine. Result The results were subjected to statistical analysis by applying analysis of variance and Bonferroni test for multiple group comparisons, and graphs were plotted. The mean value of bond strength was highest for group E (modified by aluminum oxide abrasion prior to dichloromethane application), followed by group C (modified by aluminum oxide abrasion prior to monomer application), group D (modified by dichloromethane application), group B (modified by monomer application), and lastly group A (control group). Significantly improved bond strength values were obtained in modified groups as compared with the control group. Conclusion Dichloromethane application followed by aluminum oxide abrasion provided the highest bond strength and is recommended to prevent debonding of the teeth from the denture base.

Evaluation of Shear Bond Strength of Three Different Acrylic Resin and Artificial Denture Teeth with and without Monomer Application

To compare and evaluate the shear bond strength of the tooth-denture base junction when three different commercially available acrylic resin base bonded to acrylic teeth with and without application of methyl methacrylate monomer on ridge lap area. A three-stepped cylindrical shaped die was customized. Sixty samples were fabricated with heat cure and self-cure acrylic resin with and without monomer application. A total of 60 samples were divided into three groups and six subgroups. • Group A-Twenty samples of Trevlon-HI heat-activated acrylic resin. • Subgroup A1-Ten samples of acrylic teeth bonded with Trevlon-HI heat-activated acrylic resin with the application of monomer on ridge lap area. • Subgroup A2-Ten samples of acrylic teeth bonded with Trevlon-HI heat-activated acrylic resin without application of monomer on ridge lap area. • Group B-Twenty samples of Trevalon heat-activated acrylic resin. • Subgroup B1-Ten samples of acrylic teeth bonded with Trevlon heat-activated acrylic resin with the application of monomer on ridge lap area. • Subgroup B2-Ten samples of acrylic teeth bonded with Trevlon heat-activated acrylic resin without application of monomer on ridge lap area. • Group C-Twenty samples of Trevlon-RR self-activated acrylic resin. • Subgroup C1-Ten samples of acrylic teeth bonded with Trevlon-RR self-activated acrylic resin with the application of monomer on ridge lap area. • Subgroup C2-Ten samples of acrylic teeth bonded with Trevlon-RR self-activated acrylic resin without monomer application on ridge lap area. Samples obtained from high impact heat cure acrylic resin with monomer application shows higher bond strength when tested under the universal testing machine. With and without monomer application on high impact polymethylmethacrylate (PMMA) resin and Heat cured resin it was found that high impact shows better bond strength. Trevlon HI monomer shows a greater increase in strength due to the presence of cross-linking agents. The incorporation of mechanical surface treatments followed by monomer application significantly influences the bonding between denture teeth and denture base resin.