Comparative evaluation on wear resistance of metal sleeve, sleeve-free resin, and reinforced sleeve-free resin implant guide: An in vitro study.

BACKGROUND: In-office three-dimensional (3D) printers and metal sleeveless surgical guides are becoming a major trend recently. However, metal sleeve-free designs are reported to be more prone to distortion which might lead to variation in the inner diameter of the drill hole and cause deviation and inaccuracy in the placement of the implant. Carbon fiber nanoparticles are reported to improve the properties of 3D printing resin material in industrial application. AIM: The purpose of the study is to evaluate and compare the wear resistance of 3D-printed implant guides with metal sleeve, sleeve-free, and reinforced sleeve-free resin to the guide drill. MATERIALS AND METHODS: A total of 66 samples with 22 samples in each group. Three groups including 3D-printed surgical guide with metal sleeve (Group A), without metal sleeve (Group B), an carbon fiber reinforced without metal sleeve (Group C) were included in the study. All samples were evaluated before sequential drilling and after sequential drilling using Vision Measuring Machine. The data were tabulated and statistically evaluated. RESULTS: The data obtained were statistically analyzed with one-way analysis of variance and posthoc test. The data obtained for wear observed in the samples showed that the wear was highest in Group B with a mean of 0.5036 ± 0.1118 and the least was observed in Group A with a mean of 0.0228 ± 0.0154 and Group C was almost similar to Group A with mean of 0.0710 ± 0.0381. The results showed there was a significant difference between Group B with Group A and C, respectively (P < 0.05). The results showed that there was no significant difference regarding the wear observed between Groups A and C (P > 0.05). CONCLUSION: The wear observed in the guide with a metal sleeve and carbon fiber reinforced without a metal sleeve was almost similar. The carbon fiber-reinforced guide showed better tolerance to guide drill equivalent to metal sleeve. Thus, carbon fiber nanoparticles reinforced in 3D printing resin have shown improved strength and can be used as a good replacement for a metal sleeve for an accurate placement of the implant.

The impact of extended pulp chamber preparations on the clinical performance of endocrowns in Indian patients: A 1-year observational study.

Purpose: The limitations of foundation restorations have been reduced with the advent of endocrowns. Despite their success, the extent of endocrowns tooth preparation into the pulp chamber has not been fully explored in the literature. The study aimed to evaluate the clinical performance of endocrowns with 5 mm extended pulp chamber tooth preparations in Indian patients over a 1- year period using modified USPHS criteria. Methods: The observational study recruited 36 participants with definite criteria. Ceramic crown was planned for all the participants. Conventional endocrown tooth preparation was made with 5 mm pulpal extension. Clinical assessments were made at 0-, 6- and 12-months intervals using modified USPHS criteria. The data was statistically analyzed using Friedman test and Wilcoxon signed rank test. Results: One patient (2.8%) experienced loss of retention, marginal adaptation, and loss of anatomical form during 1-year follow up period. The majority of the participants (97.3%) reported no discomfort and high satisfaction. (P < .05) No opposing tooth wear was observed at 0- and 6-months. The results showed statistical significance in the parameters of retention, marginal adaptation, loss of anatomical form, and patient satisfaction. (P < .05). Conclusion: The clinical performance of endocrowns with extended pulp chamber preparation was satisfactory for a period of 12 months.

Comparative evaluation of hemispheric and masticatory laterality in complete dentures with two occlusal schemes - A prospective cohort study.

Purpose: The lateralization can influence the choice of occlusion scheme, patient comfort and success of the prosthesis. The existence of favored masticatory side in complete denture patients and its influence with various occlusal schemes is less analyzed in the literature. The study objective was to compare the masticatory and hemispheric laterality in complete denture subjects rehabilitated with 2 different occlusal schemes at different time intervals. Methodology: The cohort study recruited 26 patients in each group of balanced and non-balanced occlusion with definitive criteria. Conventional procedures were followed in denture fabrication. The hemispheric and masticatory laterality for all participants were established at 0,1,3- and 6-month intervals. The laterality was categorized as preferred chewing side (CPCS), predominant preferred chewing side (PPCS) and observed preferred chewing side (OPCS). The data on chewing side preference was analyzed by chi square test. (α = 0.05). Results: Right side preference was predominant in 86.1% of non-balanced and 60.1% of balanced occlusion participants. The side preference among the 2 laterality and across time interval decreased in masticatory laterality of balanced occlusion participants (P < .05) when compared to non-balanced occlusion. (P > .05). Conclusion: The balanced occlusion dentures had lesser masticatory side preference when compared to non-balanced occlusion complete denture.

Tongue training technique for guiding the mandible in establishing horizontal jaw relation in edentulous patients.

BACKGROUND: Edentulous patients have poor neuromuscular proprioception to guide the mandible to the desirable horizontal relation. Horizontal jaw relation is a complex relationship in which variation may occur in vertical, anteroposterior and mediolateral directions. OBJECTIVE: The aim of this study was to train the tongue and bring the mandible to centric relation in geriatric edentulous cases. MATERIALS AND METHODS: Protrude the tongue to the maximum length and retract back to centric relation, move the tongue on the left side beyond the angle of the mouth and bringing back to centric relation, move the tongue on the right and left side beyond the angle of the mouth and bringing back to centric relation, then the tongue should move upwards and touches the marginal tubercle of upper lip and bringing back to centric relation and move the tongue upward and posteriorly to touch the posterior part of the hard palate of the maxilla and swallowing. RESULTS: Edentulous patient can successfully move the mandible in centric relation after training the tongue. CONCLUSION: The present technique is useful for establishment of horizontal jaw relation in edentulous cases using tongue training exercise in Prosthodontic dentistry.

Estimation of alpha amylase, cortisol, and pH level in saliva of patients wearing conventional and Biofunctional Prosthetic System complete dentures: A parallel randomized clinical trial.

STATEMENT OF PROBLEM: Biofunctional Prosthetic System (BPS) complete dentures have been reported to maintain a harmonious relationship with the surrounding oral structures and provide improved adaptation compared with conventional complete dentures. However, an evaluation of salivary changes and its constituents between BPS and conventional dentures is lacking. PURPOSE: The purpose of this parallel randomized clinical trial was to evaluate the alpha amylase, cortisol, and pH levels in saliva in participants provided with conventional and BPS complete dentures. MATERIAL AND METHODS: Sixteen completely edentulous participants were recruited for providing with conventional and BPS dentures (n=8). The levels of alpha amylase, cortisol, and pH in their saliva were evaluated by using an enzyme-linked immunosorbent assay (ELISA), colorimetric, and pH meter before insertion and 1 week and 1 month after denture insertion. The data were analyzed with repeated measure ANOVA and the Student t test (α=.05). RESULTS: The mean ±standard deviation for pH was 6.94 ±0.22 in conventional complete dentures and 7.04 ±0.12 in BPS dentures; for alpha amylase, it was 206.75 ±14.64 and 210.88 ±15.72 IU/mL; and for cortisol, it was 0.29 ±0.05 and 31 ±0.04 nmol/L before insertion and 1 week and 1 month after denture insertion. From the repeated measures ANOVA, the mean pH and salivary cortisol were not statistically different (P>.05), but salivary amylase was statistically different (P<.05). The Student t test showed no significant difference in pH (P>.05), but a statistically significant difference in alpha amylase and salivary cortisol levels was found between the 2 groups (P<.05). CONCLUSIONS: No significant difference in salivary pH was found in completely edentulous patients provided with conventional or BPS dentures, but significant differences were found in levels of alpha amylase and salivary cortisol.

Estimation of differences and reapplication effect of peel bond strength between silicone-based and water-based adhesives.

STATEMENT OF PROBLEM: Retention is essential for maxillofacial prosthesis. Adhesives are commonly used for retention because of their simplicity, availability, and cost-effectiveness. Studies that have estimated the differences in bond strength between the types of adhesives and the impact of reapplication are sparse. PURPOSE: The purpose of this observational clinical study was to estimate the peel bond strength and reapplication effects of water-based and silicone-based adhesives at 0, 24, and 48 hours. MATERIAL AND METHODS: A total of 46 participants were enrolled, with 23 participants in each adhesive test group-water-based and silicone-based adhesive. Silicone elastomeric strips were attached to the ventral aspect of the participants' forearm 5 cm away from the radial styloid prominence. The strength of each adhesive group was tested at 0 hours, and its reapplication effects were evaluated at 24 and 48 hours. The peel bond strength was estimated by using a universal testing machine, and the data were recorded in N/m and statistically analyzed by the independent Student t test and Spearman rho correlation coefficient tests (α=.05). RESULTS: The mean ±standard deviation of peel bond strength at 0 hours for silicone-based adhesive (111.5 ±2.5 N/m) was higher than that for water-based adhesive (99.9 ±3.9 N/m) (P<.001). On reapplication, the silicone-based adhesive had a higher peel bond strength (113.5 ±2.8 N/m) than the water-based adhesive (105.2 ±3.0 N/m) (P<.001). The results were statistically significant between the 2 groups at different time intervals (P=.04). CONCLUSIONS: The mean peel bond strength of the silicone-based adhesive was higher than that of the water-based adhesive. The reapplication of adhesives improved the bond strength in both the groups.

Effect of Cathodic Arc Plasma Deposition on Shear Bond Strength between Palladium Cobalt Chromium Coated with Titanium Nitride and Titanium Aluminium Nitride with Ceramic.

BACKGROUND: The success of esthetic ceramo-metal restoration is strongly influenced by its bond strength. The success of ceramo-metal restoration is subjective to its bond strength. AIM AND OBJECTIVES: The aim of this study is to evaluate the shear bond strength between palladium-based cobalt chromium (Co-Cr) alloy coated with titanium nitride (TiNi) and titanium aluminum nitride with feldspathic ceramics. MATERIALS AND METHODS: According to the International Organization for standardization 9693; technical report 1,140,640 samples were prepared using Palladium-based Co-Cr alloy with ×4 vertical projection resting on 5 mm diameter base. The samples were divided into Group: A (control), Group: B (Sandblasted), Group: C (TiNi coated), and Group: D (titanium aluminum nitride coated by cathodic arc plasma deposition, following which feldspathic ceramic application was performed. Shear bond test was performed using universal testing machine and surface analysis was performed using scanning electron microscope. RESULTS: The mean shear bond strength for Group A was 172.994 ± 3.739 N, Group B 209.485 ± 5.913 N, Group C 176.536 ± 4.780 N, and Group D 260.576 ± 16.351 N. Comparison within the groups was made using one-way ANOVA, and multiple group comparisons were made using Tukey's honestly significant difference Post hoc test where the P < 0.001was considered statistically significant. CONCLUSION: Palladium based Co-Cr alloy coated with titanium aluminum nitride by cathodic plasma arc deposition showed maximum shear bond strength with feldspathic ceramic compared to noncoated, sandblasted, and TiNi coated alloy.

Comprehensive Review and Comparison of the Disinfection Techniques Currently Available in the Literature.

The goal of disinfection in the dental office is to prevent the spread of infection from one patient to another and maintain the safety of the dental care providers. Prevention of cross infection has significant effect on infection control. The standard procedure of rinsing impressions under tap water immediately after removal from the mouth eliminates microorganisms along with saliva and blood. A broad search on published literature was done using the keywords impression materials, disinfection method, and sterilization of dental impression from 1980 to 2016 in Medline, Google Scholar, the internet, and textbooks. This article critically analyzes the various published methods of dental impression disinfection in dentistry.

Evaluation of shear bond strength between maxillofacial silicone and fiber-reinforced composite resin after various surface treatments.

STATEMENT OF PROBLEM: The most common reason for remaking a facial prosthesis is the debonding of maxillofacial silicone from the substructure. Improved bonding would help overcome this problem. PURPOSE: The purpose of this in vitro study was to evaluate the shear bond strength between maxillofacial silicone and fiber-reinforced composite resin after various surface treatments. MATERIAL AND METHODS: Acrylic resin specimens were prepared with a dimension of 14.4 mm in diameter and 25 mm in height with a depression of 5 mm in depth and 8 mm in diameter, according to International Organization for Standardization technical specification (ISO/TE) 11405:1994. Fiber-reinforced composite resin was dispensed and packed into the depressed part of acrylic resin and allowed to polymerize. A total of 120 specimens were fabricated, and primer was then applied over the specimens. They were washed with acetone and subjected to various surface treatments, including airborne-particle abrasion, silicon carbide paper abrasion, and laser etching. The maxillofacial silicone was mixed according to the manufacturer's instructions and packed into the cylindrical die with dimensions of 3 mm in thickness and 8 mm in diameter. The shear bond strength test on the specimens was carried out in a universal testing machine at a 5-mm/min crosshead speed, at 24 hours after fabrication and 200 hours after accelerated aging. The values were statistically analyzed using 1-way ANOVA and the Tukey honest significant difference (HSD) post hoc test. RESULTS: The mean shear bond strength values of the control group was 24.7 ±2.1 MPa, 26.9 ±1.8 MPa for the airborne-particle abraded group, 28.4 ±1.9 MPa for the silicon carbide abraded group SiCp, and 33.4 ±1.8 MPa for the laser-treated specimens at 24 hours after fabrication and 34.2 MPa at 200 hours after accelerated aging. CONCLUSIONS: The shear bond strength between the maxillofacial silicone and the fiber-reinforced composite resin was increased after laser surface treatment compared with airborne-particle abrasion and silicon carbide paper abrasion 200 hours after accelerated aging.

Evaluation of Proportion between Incisal Edge to Gingival Zenith Distance and Interdental Papilla in Maxillary Anterior Dentition of Indian Population.

INTRODUCTION: Not many investigations have evaluated the relationship between the height of the interdental papillae, gingival zenith and maxillary anterior teeth. The assessment of these parameters can aid in fabricating definitive aesthetic restoration. AIM: The aim of this study was to evaluate the existence of proportional ratio between the incisal edge to gingival zenith (HGZ) and the tip of the interdental papilla (HIP) in maxillary anterior teeth for Indian population. MATERIALS AND METHODS: One hundred healthy volunteers with an average age of 25-30 years comprised the evaluation group. Impression was made using irreversible hydrocolloid impression material and type IV Dental stone cast was made. A calibrated digital caliper measured the distance between HGZ and HIP. The values for all six maxillary teeth were recorded and the proportional ratio was evaluated and statistically analysed. RESULTS: The mean ratio between HGZ and HIP of all maxillary anteriors in 1(st) and 2(nd) quadrant was 1.80, 1.71, and 2.03 in central incisor, lateral incisor and canine respectively with p-value > 0.9. CONCLUSION: The mean proportional measurements for maxillary anterior teeth were determined and no definitive proportion existed between HGZ and HIP of maxillary anterior teeth.