Treatment Of Partial Edentulism Research Articles

Optimization of the Manufacturing Process by Molding Cobalt-Chrome Alloys in Assembled Dental Frameworks

In oral rehabilitation, the treatment of partial edentulism (PEd) is performed by removable partial dentures (RPD) or assembled prosthetic works (APW) composed of several components, fixed to the prosthetic field (Pa) and a removable one (Pb), in order to facilitate the daily hygiene but also the damping of the occlusal forces applied in mastication. Cobalt-Chromium alloys are materials used to manufacture modern prosthetic assembles. In order for this study to be relevant, it was necessary to standardize the design of the framework (Pa) in terms of shape and volume so that the experiment could be reproducible for the five Co-Cr alloys: 0-A (Co-Cr-Mo), 5-A and 10-A (Co-Cr-Mo-W), 15-A and 16.4-A (Co-Cr-W-Fe) and for the three fabrication methods of dental assembled prosthetic frameworks: refractory duplicate method (RD) resulting removable framework (Pb), direct construction method (DC) resulting removable framework (Pb-) and casting over metal method (CoM) resulting removable framework (Pb+). The time allocated to the adaptation process (AP), mechanical processing and sandblasting, in order to assemble the two components was between 43–70 min, even though the assembly between the Pa-framework and the complementary framework (Pb+) was not necessary, CoM-method hs been provide the elimination of AP step. By applying the arithmetic simple rule of three, the percentages for each of the three methods used were calculated, the values of the difference were obtained. The CoM method improves the joining precision between the components of the removable assembly of prosthetic frameworks by 91.7% compared to the RD method and by 80.62% compared to the DC method. According to the efficiency of the methods used in the precision of joining between frameworks components, their order is: casting over metal, direct construction and refractory duplicate method.

Biologic outcome of implant-supported restorations in the treatment of partial edentulism. part I: a longitudinal clinical evaluation.

The purpose of this study was to predict the outcome of implant restorations in the treatment of partial edentulism, taking into account implant interdependency and the effect of several confounding variables. Between December 1982 and June 1998, 1956 Brånemark system implants (1212 and 744 in the maxilla and mandible, respectively, 846 distal to first premolars) were installed in 660 patients (248 males) at the Department of Periodontology of the University Hospitals of the Catholic University of Leuven. Of the 810 restorations installed at the Department of Prosthetic Dentistry of the same hospital, 235 were single crowns, 166 were supported by implants and teeth and 409 were free-standing fixed partial prostheses. An additional 87 restorations was placed in private dental offices and were not included. The patients were followed from implant installation until June 1999. The estimated cumulative survival rates were 91.4% for all implants and 95.8% for all restorations over a period of 16 years. Estimated cumulative survival rates from loading for implant-tooth connected and free-standing implants were, respectively, 93.6% and 97.2%. Neither jaw site nor implant position (anterior-posterior) had any significant effect on the outcome. Short implant length, high number of implants per patient, low number of implants per prosthesis, implants loaded by acrylic-veneered restorations and implants combined with bone grafting present a higher risk hazard for implant failure. The idea of not splinting the implants in a fixed partial prosthesis is promising but needs replication before accepting it.

Biologic outcome of implant-supported restorations in the treatment of partial edentulism. Part 2: a longitudinal radiographic study.

The purpose of this study was to evaluate over time the marginal bone level changes around implants installed to treat partial edentulism and to investigate the possible effect of several confounding variables. Consecutive intraoral radiographs taken with the paralleling technique were used. In all, 660 partially edentulous patients ever treated in the departments (248 males; 15-83 years of age) with 1655 implants, which were successfully integrated at abutment connection, were loaded by means of fixed partial prostheses. The observation period starting at abutment connection reached 16 years (mean 5.1). Implants were divided into three groups: 235 implants supported single-tooth crowns, 398 supported implant-tooth connected and 1022 free-standing fixed partial prostheses. Implants were placed in maxilla and mandible, both anteriorly and posteriorly. No significant difference in bone level evolution was predicted between the three groups of implants, either for posterior or for anterior sites. The estimated marginal bone loss for the first 6 months is 0.31 mm/year and after that 0.015 mm/year higher in the maxilla than in the mandible. More bone loss was predicted for the first 6 months when dehiscences existed, when a membrane or a bone graft were used, or when metal/ceramic prosthesis material was applied. Age and gender did not affect the change in bone level. The use of subsequently situated single-implant crowns to restore an edentulous space did not lead to more marginal bone loss than around splinted implants. Based on marginal bone height maintenance, the excellent prognosis of the presently used implants to support restorations in the treatment of partial edentulism was confirmed.

Long-term clinical effectiveness of oral implants in the treatment of partial edentulism. Seven-year life table analysis of a prospective study with ITI dental implants system used for single-tooth restorations.

One hundred and eight-seven ITI implants were prospectively followed from November 1992 to July 2000, in order to evaluate the clinical efficiency and the long-term prognosis in 109 partially edentulous patients (69 women and 40 men; average age 41.3 years). Of these 187 implants, 69.5% were placed in the mandible and 30.5% in the maxilla. After a healing period that ranged from three to six months, the osseointegrated implants (n = 184) were restored with single crowns. Three implants were extracted prior to loading the fixture and were considered early failures. Each implant was reassessed on a yearly basis, both clinically and radiographically. The results of the investigation, which were evaluated according to predefined success criteria, were reviewed in accordance with a life table method. During the follow-up, six cases were deemed to be late failures. In each of these cases, a suppurative infection of the peri-implant tissue was diagnosed: in one implant, the infection could not be eradicated and the implant was removed. When 11 drop-outs were included in the analysis, the cumulative survival and success rates for the whole sample group were 96.77% and 93.6%, respectively. When only prosthetically loaded implants were considered, the results increased to 99.35% for the cumulative survival rate and 96.18% for the cumulative success rate. The analysis on disaggregated data showed better results for maxillary restorations (survival rate 100%) in comparison to mandible restorations (survival rate 95.11%). It was concluded that, under standard anatomic conditions (bone site height > 8 mm, thickness > 6 mm), prosthetic restoration of partially edentulous patients with the ITI system can be described as a reliable and efficient therapy in the long term.

Evaluation of factors influencing the marginal bone stability around implants in the treatment of partial edentulism.

The original protocol of Brånemark to achieve predictable osseointegration for oral implants has substantially been modified. One may question whether results are influenced by those modifications, especially for the long-term prognosis. The goal of the present study was to investigate the impact of those parameters that deviate from the original protocol as defined by P-I Brånemark. In this study, 246 patients with 263 fixed partial prostheses supported by 668 Brånemark implants were followed from 1 to 15 years (mean: 6.3 yr). Radiographs were taken at the time of abutment connection, at 3 to 6 months, at 12 months, and then every 3 years. The bone level was rated mesially and distally from the implants on a total of 2588 radiographs. A positive relation between abutment length and marginal bone level was found (p > .0001). The maxilla (p = .03), porcelain (p = .007), long abutments (p = .008), and regular-sized diameter implants (p = .001) all exhibited more bone loss in the first 6 months. After 6 months, only long implants showed more bone loss (p = .03). Overall, the marginal bone level remained stable around Brånemark implants, never surpassing 2.2 mm, even after 15 years. Although longer implants lost more bone over time, this has to be interpreted with respect to higher resorption rates in less resorbed jaws.

Splinting osseointegrated implants and natural teeth in rehabilitation of partially edentulous patients. Part II: principles and applications.

Lone standing splinted implant segments are accepted as optimal. However, in the treatment of partial edentulism, clinical reality often predicates the consideration of splinting teeth and implants due to variables of tooth/implant location and available bone support. This article presents a review on biomechanical aspects of splinting teeth and some considerations of splinting teeth and implants. A proposed classification of splinting applicable to both teeth and implants is presented as well as a discussion of the clinical aspects of splinting illustrated with clinical cases.

A six-year prosthodontic study of 509 consecutively inserted implants for the treatment of partial edentulism

A total of 509 consecutive Branemark TM implants (Nobelpharma AB, Gothenburg, Sweden) were inserted in 146 patients between December 1982 and May 1989, on which 217 fixed partial dentures were planned. The cumulative failure rates after abutment connection were 3.9% and 4.1% for the maxillae and mandible, respectively. The lack of continuous prosthesis stability was limited to 4.1% for the maxillae and 5.4% for the mandible. The average annual marginal bone loss was 0.77 mm (SD = 1.0) and 0.96 mm (SD = 0.9) for the maxillae and mandible, respectively, during the first year and averaged 0.1 mm for the following years. The mode of connection between teeth and implants or the use of porcelain instead of composite resin as occlusal material did not influence the marginal bone height around the implants. Technical complications were most often related to the materials used. The results of a medium-term follow-up encourage the use of the Branemark osseointegration system in the treatment of partial edentulism.

A retrospective multicenter evaluation of the survival rate of osseointegrated fixtures supporting fixed partial prostheses in the treatment of partial edentulism

Whether the excellent prognosis of the osseointegration technique also applies for the rehabilitation of partially edentulous jaws was investigated through a multicenter retrospective study. Six centers from three continents participated in the study, which included 133 fixtures in 38 patients. Forty fixtures were installed in the upper jaw and 93 in the lower jaw. The observation time varied between 6 and 36 months after prosthetic reconstruction. Clinical evaluation included mobility measurement of the restorations and control of infectious or neurologic complication. Radiologically the absence of radiolucency around the fixtures was checked by a single observer who also calculated the distance between the marginal bone and the top of the fixture. Fifty-eight percent of the prostheses were connected to natural teeth. The success rate for the individual fixtures in the upper and lower jaws was 87% and 92%, respectively. The most failures occurred before the prosthetic rehabilitation. The mean maximum distance between the margin of the bone and the fixture-abutment junction was 2.5 mm. Since only two of the 53 fixed prostheses were lost during the observation period, and since most fixture losses occurred before the prosthetic phase of the treatment, this study supports the concept that osseointegrated prostheses can also be applied to the rehabilitation of partial edentulism.

The use of microfiche in testing clinical judgment

This paper reports an investigation of the use of microfiche to replace other more bulky clinical materials in testing clinical judgment. Twenty-three students were administered two versions of tests of clinical judgment (micro-fiche and nonmicrofiche) regarding the treatment of partial edentulism. Each student served as both experimental subject and control. Results indicated that under the conditions of testing used, students preferred the nonmicrofiche version of the test. However, there was no significant difference in time of administration or grades resulting from the microfiche medium. Whether the test was given first or fourth in a series of five made a difference in time to take the test (p less than .01), and in the grade received (p less than .01). Tests taken in the first position took more time to complete and resulted in a higher grade. The rate of agreement in grading between the first and second grading session was 70 percent.