A comparative evaluation of three dimensional accuracy of different types of interocclusal recording materials - an in vitro study.

INTRODUCTION: The interocclusal registration materials record the occlusal relationship between the natural and /or artificial teeth for planning an occlusal rehabilitation in removable and fixed partial dentures. AIM AND OBJECTIVES: The aim of this in vitro study was to evaluate and compare the accuracy and the three dimensional stability offered by three different types of interocclusal recording materials at storage time intervals of 1 hour and 24 hours. METHODS: Three commercially available interocclusal recording materials were used: Group I-Polyether bite registration paste (Ramitec), Group II-Polyvinylsiloxane bite registration material (Imprint), Group III-Bite registration wax (Maarc). The test was carried out using an epoxy resin model. A total of 30 samples were made with each group consisting of ten samples. Three dimensional measurements were carried out by using 3D-Coordinate measuring machine (CMM) at time intervals of 0-1 hour and 0-24 hours in X, Y and Z-axis. RESULTS: Twelve readings were obtained for three axes (4 readings for each sample at 1 axis) and the averages of these four values were noted for a particular axis (X/Y/Z). Statistical analysis was performed using analysis of variance (ANOVA) for comparison among the groups and then Tukey's honestly significant difference (HSD) tests was performed for comparison among groups at the 0.05 level of significance. CONCLUSION: Polyvinylsiloxane was dimensionally the most stable material followed by polyether and finally bite registration wax. Dimensional accuracy and stability is influenced by both "material" and "time" factors.

Trends in Selection, Usage, and Techniques of Interocclusal Record Materials among Private Dental Practitioners: A Survey.

BACKGROUND: Majority of general dental practitioners provide fixed dental prosthesis in India. The aim of this study was to gather information on selection, usage, and materials and methods employed in interocclusal records and their communication with the dental laboratory for restorative procedures practised by dentists in Indore district to evaluate and to improve the quality of current practice. AIM AND OBJECTIVES: The purpose of this cross-sectional study was to understand and to evaluate dental practitioner's knowledge on interocclusal recording materials, its usage, their clinical implications, and their correlation with the laboratory in restorative procedures practiced by the dental practitioners in Indore district. MATERIALS AND METHODS: A questionnaire comprising 11 questions were framed and circulated among general dental practitioners except prosthodontists, and the results were statistically analyzed. RESULTS: Most of the practitioner's preferred wax (54.6%) as an interocclusal recording material over polyvinylsiloxane and polyether. Most of the dentists preferred full arch interocclusal record (27.8%). About 51.5% clinicians trimmed the interocclusal record before sending to the laboratory. CONCLUSION: From this survey, it has been concluded that the practitioner's attitude toward the use of interocclusal record materials is found to be deviated from well-acknowledged prosthodontic quality guidelines.

Prosthetic Rehabilitation of a Partially Edentulous Patient with Maxillary Acquired Defect by a Two-Piece Hollow Bulb Obturator (Using a Dentogenic Concept).

Patients may face functional, aesthetic, and social distress because of the palatal defects. Prosthetic rehabilitation of maxillectomy or developmental defect can be challenging for prosthodontists. Prognosis of the prosthetic appliances can be affected not only by patients' own ability to adapt to the prosthesis but also by the factors like the remaining teeth, bony structure, and existing mucosa. Maxillary defects are usually developed by surgical intercession of the benign or malignant conditions and trauma cases. Speech, mastication and aesthetics can be hampered by any extent of palatal defect. During obturation of palatal/maxillectomy defects, the primary intent of the prosthodontist should be the shutting of the maxillectomy defect and parting of the oral cavity from the sinonasal openings by use of different bulb designs. In the present case, dentogenic concept has been applied while fabricating the two-piece hollow bulb obturator for restoration of the defect. Well known fact about the gravitational force is that it acts on maxillary obturator and reduces its retentive qualities, this can be counteracted to some extent by making the obturator hollow. Dentogenic concept is the skill, training, and procedure of generating the chimera of natural teeth in artificial teeth during prosthodontic restorations.

A Comparative Evaluation of Accuracy of the Dies Affected by Tray Type, Material Viscosity, and Pouring Sequence of Dual and Single Arch Impressions- An In vitro Study.

INTRODUCTION: The clinician's skill, impression techniques, and materials play a very important role in recording fine details in an impression for accuracy of fixed partial denture prosthesis. Impression of prepared teeth and of the opposing arch can be recorded simultaneously by dual-arch trays, while the full arch metal trays are used for impressions of prepared teeth in one arch. AIM: To measure and compare the accuracy of working dies made from impressions with metal and plastic dual arch trays and metal full arch trays, for two viscosities of impression material and by changing the sequence of pour of working and non-working sides. MATERIALS AND METHODS: A balanced design with independent samples was used to study the three variables (tray type, impression material viscosity, and pouring sequence). An impression made by dual arch trays and single arch trays were divided in to three groups (Group A-plastic dual arch tray, Group B-metal dual arch tray, Group C-full arch metal stock tray). Out of these three groups, two groups (Group A and B) were subdivided in to four subgroups each and one group (Group C) was subdivided in to two subgroups. A sample size of 30 was used in each subgroup yielding a total 300 impressions in three groups or ten subgroups. Impressions were made of a machined circular stainless steel die. All three dimensions (Occlusogingival, Mesiodistal, and Buccolingual) of the working dies as well as stainless steel standard die were measured three times, and the mean was used for the three standard sample values to which all working dies means were compared. Statistical analysis used for this study was a 3-factor analysis of variance with hypothesis testing at α =0.05. RESULTS: With respect to the selection of impression material viscosity statistically significant differences were found in the dies for the buccolingual and mesiodistal dimensions. Metal dual arch trays were slightly more accurate in the mesiodistal dimension in comparison to the plastic trays in reference of tray selection and in view of pouring sequence no differences were observed in occlusogingival dimension but in buccolingual and mesiodistal dimensions nonworking side was more accurate. CONCLUSION: The gypsum dies produced from the dual arch impressions were generally smaller in all three dimensions than the stainless steel standard die. Plastic dual-arch trays were more accurate with rigid impression material and there was not statistically significant difference for sequence of pouring. Metal dual-arch trays were more accurate with monophase impression material and working side was more accurate. Stock metal full arch trays were more accurate for monophase impression material.

A new simplified beading and boxing procedure for elastic impression.

Beading and Boxing of impression is taught in most dental colleges. The boxing procedure is crucial step to preserve the details of the final impression especially of the vestibular area. This article describes an alternative beading-boxing procedure that is compatible with all impression materials, is efficient, simple, inexpensive, and practicable. Use of commercially available instant adhesive around the border to act as a joining agent between elastic impressions and beading wax or bead made up of base plate wax is advocated in this technique.