Fit of implant-supported fixed prostheses fabricated on master casts made from a dental stone and a dental plaster

STATEMENT OF PROBLEM: The impression and cast on which an implant-supported fixed prosthesis is fabricated must accurately reproduce the intraoral relations. PURPOSE: The fit of fixed prostheses fabricated on master casts poured in a conventional die stone and in an ultra-low-expansion plaster was investigated in vitro. MATERIAL AND METHODS: An impression was made of patient replicas with inter-implant abutment distances of 50 and 35 mm. Ten master casts were poured in a conventional die stone (Velmix, Kerr) and 10 in an ultra-low-expansion plaster (Gnathostone, Zeus). A simulated plaster fixed prosthesis was fabricated on each master cast and then returned in a random order to the appropriate patient replica. The fixed prostheses were screwed into place on one abutment with a torque of 10 Ncm. Vertical discrepancies were measured at the other abutment by an operator blinded to the cast on which the fixed prosthesis was fabricated. A 2-way analysis of variance was performed for distance and materials, and significant differences were identified with regression analysis. RESULTS: For the 50-mm inter-abutment distance, die stone master casts produced a mean vertical discrepancy of 80 microm (SD 32.50 microm). Plaster master casts produced a mean vertical discrepancy of 42.8 microm (SD 12.17 microm). The means were significantly different (P=.01). For the 35-mm inter-abutment distance, the mean vertical discrepancy produced from the die stone and plaster master casts was 84.33 microm (SD 49.9 microm) and 0 microm (SD 0), respectively. The means were significantly different (P<.001). A significant difference was found between the mean vertical seating discrepancies of fixed prostheses produced from plaster casts with inter-abutment differences of 50 mm and plaster casts with inter-abutment distances of 35 mm (P=.003). No significant differences were found between mean vertical seating discrepancies for fixed prostheses fabricated on die stone casts. CONCLUSION: In this in vitro study, master casts poured in an ultra-low-expansion plaster limited to a maximum inter-abutment dimension of 35 mm were more accurate than casts with 50-mm inter-abutment spans or those poured in a conventional die stone.     

A review of suture anchors

Suture anchors are designed to allow soft tissue to bone healing in cases where inadequate soft tissue stock on bone makes it impossible to perform a direct soft tissue-to-soft tissue repair. Suture anchor fixation is one of the most important innovations in arthroscopic glenohumeral shoulder surgery, optimizing the link between bone and soft tissue at the rotator cuff footprint. Newer developments and techniques have expanded the use of suture anchors to most other musculoskeletal tissues including the hip, elbow, hand, knee foot and ankle.Their success depends on having an understanding of the biology and biomechanics that affect their use and knowing the factors that may affect the clinical outcome. This review concentrates on the design, insertion technique, composition and evolution of suture anchors in orthopaedic surgery and the ways in which they are utilised in different tissues.     

Career anchors of dentist leaders

Objective: The work of a health care leader is demanding; in order to cope, leaders need motivation and support. The occurrence of intrinsic factors called career anchors (combination of one’s competence, motives and values) could be a contributing factor in dentist leaders’ career decisions. The aim of our study was to identify dentist leaders’ career anchors and their association to dentist leaders’ retention or turnover of the leadership position.

Material and methods: Materials were gathered in 2014 via an electronic questionnaire from 156 current (Leaders) or former (Leavers) Finnish dentist leaders. Career anchor evaluation was conducted by the questionnaire and scoring-table taken from Edgar Schein’s Career Anchors Self-Assessment. Both the most and the least important career anchors were detected by the highest and lowest scores and their occurrence reported as percentages. Associations between career anchor scores and tendency to stay were analyzed with logistic regression.

Results: ‘Technical/Functional Competence’ and ‘Lifestyle’ were most frequently reported as the most important and ‘Entrepreneurial Creativity’ and ‘General Managerial Competence’ as the least important career anchors. However, a higher level of ‘General Managerial Competence’ anchor was most significantly associated with staying in a leadership position. Instead, ‘Pure Challenge’ and ‘Lifestyle’ decreased the odds to stay.

Conclusions: The knowledge of the important and essential career anchors of dentist leaders’ and individuals’ could perform crucial part in career choices and also in planning education, work opportunities and human resource policies promoting retention of dentist leaders and probably also other health care leaders.     

Fit bleiben in der Corona-Pandemie

Der Freie Zahnarzt -     

Pedodontic prostheses

Premature loss of deciduous teeth can result in unsatisfactory dietary habits and crowding in the buccal segments of the permanent dentition. It may also affect the social development of the young child. For these reasons, the prosthetic restoration of the deciduous arch must be considered whenever teeth have been lost prematurely.     

Radiotherapy prostheses

The orofacial region performs the essential functions of mastication and speech, as well as that of appearance, which for better or worse evokes an instant and instinctive response in other people. In this region, tissue loss caused by surgical resection of a malignant tumor has a tremendous negative impact on the patient's quality of life, with deep mental and psychological repercussions. Therefore, from the standpoint of preserving form and function, radiotherapy has a major role to play in the treatment of malignant tumors in the orofacial region. That said, important organs, such as sensory organs, are present in close proximity to each other in this small region. During the irradiation process, therefore, it is important to ensure that the lesion is sufficiently irradiated while simultaneously protecting the surrounding normal tissue. In certain cases of radiotherapy of malignant tumors of the orofacial region, the use of radiotherapy prostheses can help to satisfy a basic principle of radiotherapy: that of delivering a lethal dose to the tumor while minimizing irradiation to normal tissue. In recent years, medical and dental experts have taken a team approach to creating and employing a variety of radiotherapy prostheses, working towards improving the treatment record for malignant tumors as well as reducing complications in surrounding normal tissue. As a result, patients treated with radiotherapy prostheses are now able to receive post-radiotherapy prosthodontic treatment in a dramatically safer and more rapid manner. It is clear that radiotherapy prostheses contribute significantly to the improvement of these patients' quality of life.     

Removable prostheses

Reconstruction of the dentition extensively damaged through tooth surface loss may require the use of removable prostheses. This can be the most appropriate type of treatment when either the teeth are very severely worn or the patient wishes a simpler and more economical approach than a fixed reconstruction.     

关于全瓷修复应用的一些问题

近年来,全瓷修复以其良好的美观效果引起了国内广大口腔修复工作者的关注.随着陶瓷材料机械强度的不断提高,全瓷修复体的应用,由过去单纯制作嵌体、贴面发展到全冠、固定桥,乃至种植义齿的上部结构.越来越多的患者要求进行全瓷修复,越来越多的国外全瓷材料和设备进入中国.因此,加强口腔修复医师对全瓷修复的认识,正确了解和使用不同类别的全瓷材料成为当务之急.以下谨就大家普遍关心的一些问题,结合全瓷材料的研究进展谈谈笔者的观点,希望引起进一步的讨论.