Dhanasekar Balakrishnan

CAD/CAM‐Assisted Auricular Prosthesis Fabrication for a Quick, Precise, and More Retentive Outcome: A Clinical Report

Auricular defects comprise a large proportion of maxillofacial deformities. Most patients with acquired deformities have psychosocial ineptness and seek cosmetic rehabilitation. Although minor defects can be corrected surgically, extensive deformities are difficult to reconstruct with plastic surgery. Contrary to that, prosthetic restoration can provide excellent esthetic results. The conventional methods of maxillofacial prosthesis fabrication are time consuming and the outcome depends on the technicians skill. The advent of CAD/CAM technology in the field of dentistry has brought enormous improvement in the quality of health care provided. In the past decade, several methods have been described employing CAD/CAM techniques for the cosmetic rehabilitation of auricular defects. This clinical report details the integration of multiple digital technologies of CT scanning, computer aided design, and rapid prototyping to construct an ear prosthesis with limited number of appointments.

In Vitro Comparative Evaluation of Different Types of Impression Trays and Impression Materials on the Accuracy of Open Tray Implant Impressions: A Pilot Study

Purpose. For a precise fit of multiple implant framework, having an accurate definitive cast is imperative. The present study evaluated dimensional accuracy of master casts obtained using different impression trays and materials with open tray impression technique. Materials and Methods. A machined aluminum reference model with four parallel implant analogues was fabricated. Forty implant level impressions were made. Eight groups (n = 5) were tested using impression materials (polyether and vinylsiloxanether) and four types of impression trays, two being custom (self-cure acrylic and light cure acrylic) and two being stock (plastic and metal). The interimplant distances were measured on master casts using a coordinate measuring machine. The collected data was compared with a standard reference model and was statistically analyzed using two-way ANOVA. Results. Statistically significant difference (p < 0.05) was found between the two impression materials. However, the difference seen was small (36 μm) irrespective of the tray type used. No significant difference (p > 0.05) was observed between varied stock and custom trays. Conclusions. The polyether impression material proved to be more accurate than vinylsiloxanether impression material. The rigid nonperforated stock trays, both plastic and metal, could be an alternative for custom trays for multi-implant impressions when used with medium viscosity impression materials.

An Evidence Based Restoration of Esthetically Challenged Maxillary Anterior Arch with Andrews Bridge System - A Case Report with 5 Years of Follow Up

The replacement of missing teeth and restoration of alveolar contour has always presented a problem in those patients who have suffered traumatic injuries to the anterior dentition and alveolar processes. Many of these injuries lead to excessive loss of the residual ridge and make it extremely difficult to restore with a conventional fixed prosthesis. Due to constrain of fixed pontic in relation to these residual ridges, the use of this modality is virtually eliminated as a successful means of restoring such defects. An approach to the treatment in such patients has been conceived whereby a removable pontic section is supported directly by adjacent abutment teeth in a manner similar to that of fixed prosthesis. This case report represents restoration of esthetically compromised partially edentulous maxillary anterior arch with a fixed-removable prosthesis. This article also illustrates the indications, advantages, disadvantages and limitations of the Andrews bridge system.

A comparative evaluation of linear dimensional accuracy of the dies obtained using three conceptually different die systems in the fabrication of implant prosthesis: an in vitro study.

STATEMENT OF PROBLEM Given that meticulous implant prosthodontic procedures are recommended to obtain the best possible intraoral fit, the die systems used for multi implant casts warrant further investigation. Die stone expansion and errors introduced by removable die casts may exceed the accuracy required for the passive fit of implant prosthesis. PURPOSE The purpose of the study was to evaluate the linear dimensional accuracy between the implant master die and three conceptually different die systems such as Pindex system, Accu-trac precision die system, and Conventional brass dowel pin system. MATERIALS AND METHODS Thirty impressions of implant master die were made with polyether impression material. Ten experimental implant casts were fabricated for each of the three different die systems tested: Accu-trac precision die tray system, Pindex system, and conventional brass dowel pin system. The solid experimental casts were sectioned and then removed from the die system 30 times. Linear distances between all six possible distances were measured from one centre of the transfer coping to the other, using a co-ordinate measuring machine in millimeters up to accuracy of 0.5 microns. Data were tabulated and statistically analyzed by Binomial non parametric test using SPSS version 15. RESULTS Significant differences were found for distance A-B (P = 0.002), A-C ( P = 0.002), A-D (P value = 0.002), and B-D ( P = 0.021) in Conventional Dowel pin system however for Accu-trac precision die tray system, it was significant only for distance A-D (P = 0.002) but for Pindex system it was non-significant for all the distances measured. CONCLUSION Within the limitations of this study, use of Pindex system is recommended when sectioned dies are needed for a multi implant retained prosthesis.

Comparison of the effect of different surface treatments on the bond strength of different cements with nickel chromium metal alloy: An in vitro study

Background For success of any indirect metal restoration, a strong bond between cement and the intaglio surface of metal is imperative. The aim of this study is to evaluate and compare the effect of different surface treatment on the tensile and shear bond strength of different cements with nickel–chromium alloy. Material and Methods 120 premolars were sectioned horizontally parallel to the occlusal surface to expose the dentin. Wax patterns were fabricated for individual tooth followed by casting them in nickel chromium alloy. 60 samples were tested for tensile bond strength, and the remaining 60 for shear bond strength. The samples were divided into three groups (of 20 samples each) as per the following surface treatment: oxidation only, oxidation and sandblasting, or oxidation, sandblasting followed by application of alloy primer. Each group was subdivided into 2 subgroups of 10 samples each, according to the bonding cement i.e RM-GIC and resin cement. Samples were subjected to thermocycling procedure followed by evaluation of bond strength. Results Two-way analyses of variance (ANOVA) was performed to compare the means of tensile and shear bond strength across type of surface treatment and cement, followed by post hoc parametric analysis. For all tests ‘p’ value of less than 0.05 was considered statistically significant. Conclusions The surface treatment of oxidation and sandblasting followed by application of alloy primer offered the maximum tensile and shear bond strength for both RM GIC and resin cement. Resin cement exhibited greater tensile and shear bond strength than RM-GIC for all the three surface treatment methods. Key words:Resin cement, resin modified glass ionomer cement, oxidation, sandblasting, alloy primer, tensile bond strength, shear bond strength, universal testing machine.

Implant placement with guided bone regeneration in the maxillary aesthetic zone - A case report with 3 years of follow up

The placement of implants in a prosthetically driven position depends on the quantity and quality of available bone especially in the anterior region of maxilla. Implant placement and its restoration becomes clinically challenging when the alveolar ridge lacks sufficient bone volume. Additional surgical procedures are required to augment the bone deficiency in such clinical situations. Advanced procedures such as guided bone regeneration provides a conducive environment for successful placement of implants, where non-osseous cells are inhibited and osteoblast derived from the periosteum and the bones are induced to form new bone. This article presents a case report of simultaneous approach of guided bone regeneration and implant placement in the maxillary anterior with narrow ridge defect. After six months of healing period implant was aesthetically restored. Correspondence to: Manawar Ahmad, Assistant Professor, Department of Prosthetic Dental Sciences, College of Dentistry, Jazan University, Saudi Arabia, E-mail: ahmad955mls@gmail.com

Prosthetic Management of Total Glossectomy Patients

Corresponding Author: Dhanasekar Balakrishnan, Professor and Head, Department of Prosthodontics and Crown & Bridge Manipal College of Dental Sciences, Manipal, Karnataka, India Phone:+919742444184, e-mail: docdhana@hotmail.com ABSTRACT Background: Total glossectomy impairs various functions of tongue, such as mastication, speech, swallowing, and also results in psychological breach for the patient during social activities. In a glossectomy patient, the new size of the oral cavity often produces a change in the resonance associated with certain sounds. Also, due to the decrease in size and function of the tongue, interruption occurs in articulation patterns between the tongue, the hard and soft palate, and the teeth.

Comprehensive Rehabilitation of Partially Amputated Index Finger with Silicone Prosthesis: A Case Report with 3 years of Follow Up

The loss of all or part of a finger following traumatic amputation may have a negative impact on physical and psychological well-being. An esthetic prosthesis can offer psychological, functional, and rehabilitative advantages. One of the major problems associated with somato-prosthetic replacement of partially amputated finger is inadequate retention of the prosthesis. This may stem from the weight of the prosthesis, inadequate tissue support, and/or the particular area of the finger to be replaced. A number of means have been employed to enhance retention. Among the more common are adhesives, adhesive tape, magnets and implants. The purpose of this article is to describe a technique which eliminates the need for adhesive materials and utilizes copper wire to fabricate a finger ring as a primary means of retention. This technique can be utilized whenever the prosthesis encompasses more than 180° of the affected area. This clinical report presents a case of rehabilitation of a partially amputated index finger defect and describes a method of retention for the same with a copper ring.