The Accuracy of Casts Obtained Using Different Impression Techniques and Impression Materials in Combined Parallel and Angulated Implants: An In Vitro Study.

Aim The aim of this in vitro study was to evaluate and compare the accuracy of casts made from two elastomeric impression materials (polyvinyl siloxane (PVS) and vinylsiloxanether (VSE)) using different impression techniques on parallel and angulated implants. Materials and methods The reference model was fabricated using auto-polymerizing acrylic resin on which three implant analogs were placed of which two were parallel to each other and the third at 20-degree mesial angulation. A total of 60 impressions were made of which 30 were by using PVS and 30 by VSE. For each material, 10 impressions were made by closed tray technique, 10 by open tray technique and 10 by open tray with sandblasting and adhesive coating of the impression copings technique. The inter-analog distances of the casts obtained were evaluated and compared with the reference model by a vision measuring machine. Data were analyzed using analysis of variance (ANOVA), Tukey's Honest Significant Difference (HSD) post hoc and independent samples t-test. Results When the inter-analog distances of the duplicate casts were compared with the reference model, the mean error rates for parallel implants decreased in the order of closed tray technique, open tray technique and open tray with sandblasting and adhesive coating of the impression copings technique for both PVS and VSE impression materials. Similarly, the same order was observed for angulated implants for both impression materials. Using the closed tray technique, there was no statistically significant difference in the accuracy of the cast between the two materials for parallel implants (P = 0.525) and also no significant difference between the two materials for angulated implants (P = 0.307). Similarly, there was no statistically significant difference in the accuracy of the cast between the two materials for parallel implants (P = 0.455) and also no significant difference between the two materials for angulated implants (P = 0.519) using the open tray technique. Whereas for the open tray with sandblasting and adhesive coating of the impression copings technique, VSE produced a more accurate cast than PVS for parallel implants and was statistically significant (P = 0.033); however, there was no significant difference between the two materials for angulated implants (P = 0.375). Conclusion For parallel implants, VSE by an open tray with sandblasting and adhesive coating of the impression copings technique produced a more accurate cast than PVS. For angulated implants, there was no significant difference between the two materials and it was only the technique that significantly affected the accuracy of the cast.

An Aesthetic and Economic Approach of Smile Designing for a Patient With Dentinogenesis Imperfecta: A Rare Case Entity.

This is a case report presenting a female patient in her twenties suffering from severely stained, unaesthetic, and worn-out teeth since her childhood. It was a major aesthetic and functional concern for her. This clinical presentation describes the prosthetic rehabilitation of a patient with generalized discolored and worn-out teeth to have enhanced aesthetics and masticatory function of the patient. This is a referred case of dentinogenesis imperfecta- II (DGI-II) from the Department of Oral Medicine and Radiology and Oral Pathology, as diagnosed by them after a thorough clinical, radiographical, and histopathological examination. DGI is a disorder of teeth characterized by discoloration and rapid wear and belongs to a group of disorders of the development of teeth. Due to the rapid wear and generalized intrinsically stained and discolored teeth, there is a loss of vertical dimension of occlusion (VDO) and an unesthetic look of the patient respectively. Therefore, the main objective of the case report is to re-establish the aesthetic and regain the VDO and functionality of the damaged teeth using the Pankey Mann Schuyler philosophy in which the first anterior teeth were rehabilitated with porcelain fused to metal (PFM) crowns based on aesthetics and phonetics of the patient. This was followed by posterior PFM crowns based on Broadrick's flag analysis for posterior occlusal plane determination and centric occlusion.

Pankey Mann Schuyler Philosophy-Based Prosthetic Rehabilitation for an Amelogenesis Imperfecta Patient: A Case Report.

This clinical case report presents the prosthetic rehabilitation of a 23-year-old male patient with generalized discolored and worn-out teeth, which were of aesthetic and functional concern. In collaboration with the Department of Oral Medicine and Radiology and Oral Pathology, this clinical condition was diagnosed as amelogenesis imperfecta (AGI). AGI is a genetic odontological disorder that is an epithelial derivative of the developed tooth bud with enamel malformation. AGI typically affects both deciduous and permanent teeth. Patients generally have aesthetic complaints and compromised chewing efficiency with loss of vertical dimension. Prosthetically rehabilitating an AGI patient is a multidisciplinary approach to regain aesthetics, phonetics, and mastication. This article describes the full mouth rehabilitation, following the Pankey Mann Schuyler philosophy, of the patient with AGI involving all teeth. Full mouth rehabilitation was planned to restore aesthetics, phonetics, and mastication in four phases. First was prosthetic rehabilitation of the mandibular anterior teeth, followed by the maxillary anterior, mandibular posterior, and, finally, maxillary posterior teeth.

Finger Prosthesis: An Economic and Esthetic Approach.

Fabrication of prosthetic fingers is more of an art than a science. The prosthetic finger must match the missing fingers or digits to such an extent to have a natural aesthetic look for the patient. This would build up the patient's confidence and prevent unwanted attraction by others. A patient, 47 years old, reported the loss of the middle finger of the right hand. The loss of the right middle finger was till the first phalanx, and it was distorted till the second phalanx. The patient wanted to have a natural look at his hand. Alginate impressions of the patient's amputated finger and the donor's relevant matching fingertip were made. A waxed prosthesis pattern was fabricated with the donor's fingertip. A wax trial was done in the patient, and was flasked. A heat cure acrylic was intrinsically painted with acrylic paint color to match the adjacent finger's skin tone, followed by packing these in the dewaxed mold, processed, trimmed, finished, and polished. This case report describes a method of obtaining or enhancing retention of the prosthetic finger by adopting a customized finger ring on the master cast and also customizing the prosthesis in the clinical rest position to have the aesthetic appearance in the resting condition of the palms and fingers. This method is cheaper and very easy to be adopted for affected people.

Evaluation and Comparison of Stress in Divergent and Convergent Collar Designs of Implants With Different Bone Densities: A Finite Element Study.

BACKGROUND: The failure and the success rate of an implant depends on biomechanical factors, esthetics and painless sterile implant surgery conditions, out of which stresses applied to the bone and its surrounding, bone-implant interface, material characteristics of the implant used and the strength of the bone and its surrounding are the important factors. This study aimed to evaluate the stress distribution of divergent collar design (DCD) and convergent collar design (CCD) implants placing them in four different densities of the bone (D1, D2, D3 and D4). The evaluation of the stress distribution of DCD and CCD was performed using the 3D finite element method (FEM), by placing them in four different bone densities. In addition to this, a comparison of the effect of DCD and CCD in terms of stress distribution in the bone was also done. MATERIALS AND METHODS: The software used to process the geometric characteristics of the missing first molar in the mandibular section were Ansys, version 19.2, CATIA, version 5, and Solidworks (Dassault Systèmes). Using these software, three models were designed and successfully restored using an all-ceramic crown implant. The first model was a geometric model of the first molar mandibular bone section, the second model was a cylindrical implant (4x10 mm) with a DCD and CCD, and the third model had titanium alloy (Ti-6Al-4V) properties incorporated into the implant. RESULTS: The D1 bone model showed the lowest stress concentration compared to D2, D3, D4. The DCD showed the lower stress and strain concentrations as compared to the CCD in the contiguous crestal bone in all the densities of the bone in both vertical and lateral or oblique loadings. The DCD with the D1 bone showed the least stress concentration around the crestal bone region. The results of this study also showed that the maximum von Mises stress was observed in the crestal region or the neck of the implant for both the convergent and divergent collar implant designs in all the four densities of the bone. CONCLUSION: Before a patient trial of a new implant design or a new implant material, finite element analysis (FEA) gives us a clear picture of what will be the patient bone response when an implant will be placed and loaded. FEA also gives us an opportunity to test a new implant material without putting a patient at risk. In this study, four different types of bone were incorporated with two different implant collar designs. Each implant assembly was subjected to vertical as well as oblique forces. The response of each bone type for the titanium alloy implant was recorded. A color-coded response for the magnitude and the location of the maximum stress received by the bone was observed. Maximum stresses were seen in the crestal region. As this is a computer-based model, dynamic loading was not possible. This study provided us with the possible outcome in patients under a static load. Further studies can be conducted in vivo to record dynamic loading responses as well as long-time loading responses.

Evaluation and Comparison of the Geometrical Relationship of Tooth and Lip Arcs and Their Correlation to Smile Arcs Between Males and Females in a North Indian Population.

Background With the increasing influence of social media, millennials and the generations that follow have increasingly pressing aesthetic concerns. Following this, there has been a sea change in treatment plans and procedures as well as the choice of material. Dentistry nowadays is dependent on digital data to compute and design prostheses; these technologies are often not readily available all over the world. The purpose of this research article is to measure the tooth arc (TA) and lip arc (LA) and their correlation to the smile arcs with a cohort consisting of males and females from a single center in northern India. The SA measurement, evaluation, and comparison of smile aesthetics in this young population may be used as a threshold to these smile variables so that prosthodontists can easily prevent or modify aesthetically displeasing features. This research article will be useful for cases requiring restorations and replacements of maxillary anterior teeth. Materials and methods In this research work, photographic analysis was used and photographs of hundred subjects were taken. The camera was fixed using a tripod, at an 11-inch distance from the face, so that a clear picture of the face could be taken from the tip of the nose to the chin. A digital single-lens reflex (DSLR) camera (Nikon D-60, with the Nikon DX AF-S Nikkor 18- 135mm lens, Tokyo, Japan) was used to take the facial photographs. As the posed smile is more predictable than the natural smile, subjects were asked to smile while keeping their natural head position (NHP). Parabolas were made with Math-GV software () and superimposed on the photographs to calculate the value. Results The mean LA shows greater curvature in the female population. There was no significant (p=0.92) relationship between TA curvature in the male (0.07±0.03) and female populations (0.08 ± 0.03), whereas the LA in males (0.10±0.03) and LA in females (0.12±0.04) showed a significant relationship (p=0.03) between both groups. The LA of the female population was found to be steeper than that of the male population. This study signifies that there is no significant difference (p=0.92) between the skeletal makeup of the male and female populations but the muscular activity and muscle function differ in the male and female populations. Regarding arc-wise comparisons in both male and female populations, the male population showed a statistically insignificant (p=0.27) correlation in lip and tooth arcs. But in the female population, the correlation between these arcs was statistically significant (p=0.01). Conclusion These study results provide useful guidance for evaluating anterior teeth and planning treatment for aesthetic restorative care. Clinicians should consider not only racial and gender differences when developing an aesthetic treatment plan but also the symmetry of the facial structure which should be in harmony with the dental arc. The harmony of each determinant of aesthetics, with each other, aids in promoting beauty as a whole.