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George A Zarb

Publications and source records attributed to George A Zarb.

At least 19 recordsLinked to original sources
PubMed2003

Crestal bone loss proximal to oral implants in older and younger adults.

STATEMENT OF PROBLEM: Older adults often have bone loss and may be at risk of bone resorption around oral implants. PURPOSE: This study tested the hypothesis that there is no difference in crestal bone loss proximal to oral implants in the complete implant prosthesis sites of older and younger adults. MATERIAL AND METHODS: Two groups of 35 complete dental implant prosthesis sites (23 screw-retained fixed prostheses and 12 bar-retained overdentures) were selected by matching sites in 32 older adults (60 to 74 years old with 166 Bränemark implants) to sites in 34 younger adults (29 to 49 years old with 162 Bränemark implants) on the basis of possible confounding factors including gender, prosthetic design, implant number, arch, year of surgery, and opposing dentition. Statistical comparisons (Mann-Whitney test at P<.05) were made of mean crestal bone level at loading and mean annual crestal bone loss during the first year, first to fourth year, after first year, and after fourth year of loading with periapical radiographic measurements of the vertical distance in millimeters from the apical edge of the implant collar to the most apical initial point of contact between the implant and bone. RESULTS: No significant differences were found between the groups. Mean bone levels at loading were 1.4 mm below the collar in both groups and mean annual crestal bone loss after the first year of loading was 0.04 mm/y in both groups. However, significant differences were found between some old and young subgroups stratified by arch and prosthetic design. CONCLUSION: Within the limitations of this study, elders should expect no more rapid bone resorption around oral implants in edentulous jaws than that seen in young adults.

Adult↗
PubMed2003

Implant prosthodontic management of partially edentulous patients missing posterior teeth: the Toronto experience.

STATEMENT OF THE PROBLEM: The clinical success of implant-supported fixed partial dentures has been documented. However, few studies have reported long-term results or any association between implant outcomes and host determinants. PURPOSE: This study reports on implant and prosthesis outcomes in a group of partially edentulous patients treated with Brånemark implants in the posterior zones. It also examines factors described in the medical history that may influence implant survival. MATERIAL AND METHODS: The charts of patients treated with implants from 1983 and followed prospectively through December 2001 at the University of Toronto were reviewed. One hundred thirty partially edentulous patients treated with implant-supported restorations in the posterior zones (area distal to mental foramen) were selected. Implant and prosthesis treatment outcomes were recorded and analyzed through the Kaplan-Meier and Cox regression methods (P<.05). RESULTS: A total of 130 patients received 432 Brånemark dental implants in 174 posterior edentulous spans. The mean age of the patients at the time of insertion of the implants was 50.97 +/- 13.27 years. At 15 years, the overall implant and prosthesis survival rates were 91.6% and 89%, respectively. At 5 years, the survival rate of the wide-platform 5-mm-diameter implants was 76.3%. Implant diameter (P=.0001) and a history of a chronic medical condition (P=.01) were correlated with implant survival outcomes. CONCLUSIONS: High success of implant-supported prostheses in the posterior zones of both the maxilla and mandible. It corroborated other studies that have shown higher failure rates for wide-platform implants, emphasizing the need for proper establishment of clinical trials prior to marketing of new implant designs.

Adolescent↗
PubMed2002

Bone level changes proximal to oral implants supporting fixed partial prostheses.

The success of oral implant treatment relies on the presence and maintenance of bone adjacent to implants. The monitoring of radiographic bone level changes provides valuable insight into the longevity of oral implants. The purpose of this study was to measure radiographic bone level changes proximal (mesial and distal) to Brånemark System) implants (Nobel Biocare AB, Göteborg, Sweden) supporting fixed partial prostheses. Measurements were used to determine mean bone loss for the first year of loading by the prosthesis and the mean annual bone loss for subsequent years. These results were then compared and contrasted with various characteristics of the individuals, treatment, and treatment outcomes. Fifty-five subjects with 69 fixed partial prostheses supported by 160 implants were followed over a 1 to 12-year period. A mean bone loss of 0.33 mm (SD 0.59) was measured for the first year of loading and a mean annual bone loss of 0.00 mm (SD 0.11) after the first year. The radiographic bone loss calculated for implants at the first year of loading was positively correlated with the mean annual bone loss thereafter. Males, younger individuals and those implants supporting distal extension prostheses lost significantly more bone in the first year of loading. Larger numbers of implants followed for longer periods of time are needed to further explore the effects of various aspects of treatment on bone loss.

Adult↗
PubMed2002

A study of dental implants in medically treated hypothyroid patients.

PURPOSE: The purpose of this study was to investigate the success outcomes of implants and prosthodontic treatment placed in patients with a previous history of hypothyroidism that was being controlled with medications. MATERIALS AND METHODS: Twenty-seven female patients with a medically confirmed history of primary hypothyroid disease who were on replacement medications at the time of implant surgery were selected as the study group. They were matched with 29 control patients by age, gender, location (jaw and zone) of implants, type of prosthesis, and dental status of the opposing arch. Additional factors studied were medical history, medications, smoking habits, and bone quality and quantity. RESULTS: There was no statistical difference in the number of implant failures between the two groups (p = .781). The hypothyroid patients had more soft tissue complications (p = .018) following stage 1 surgery. More bone loss around implants in the hypothyroid patients was recorded after year 1 of loading when compared with loss in their matched controls (p = .017). CONCLUSIONS: This study suggests that medically controlled hypothyroid female patients treated with dental implants are not at higher risk of implant failure when compared with matched controls, and that a history of controlled hypothyroidism does not appear to be a contraindication for implant therapy with endosseous implants.

Adult↗
PubMed2002

Implant prosthodontic management of anterior partial edentulism: long-term follow-up of a prospective study.

OBJECTIVE: This paper reports on the long-term outcome of patients with Kennedy Class IV partial edentulism treated in the Implant Prosthodontic Unit (IPU) at the University of Toronto, Toronto, Ontario. METHODS: The information for this paper was gathered from the charts of the first 30 consecutive, partially edentulous patients treated at the IPU. These patients all had Class IV edentulism and formed part of the original prospective clinical studies that were initiated in 1983. The patients' dental history suggested maladaptive experiences with traditional removable prostheses or a reluctance to have intact or quasi-intact teeth prepared as retainers for fixed prostheses. Fifteen men and 15 women treated with 94 Br nemark dental implants, supporting 34 prostheses, were followed until June 2000 (25 patients) or until they were lost to follow-up (5 patients). The multiple missing teeth occurred in 19 maxillae and 15 mandibles. RESULTS: The original prosthodontic treatments were intended to result in 33 fixed partial prostheses and 1 overdenture. At the time of this report, 25 patients with 86 implants supporting 31 fixed prostheses and 3 overdentures had been followed for an average of 12 years (range 7 16 years). The overall survival of implants was 92%. The difference between men (94%) and women (89%) was not statistically significant. CONCLUSIONS: This report is an interim update on an ongoing long-term prospective study. The results so far demonstrate a high survival rate for Br nemark implants supporting tissue-integrated prostheses for the management of anterior partial edentulism.

Adolescent↗
PubMed2002

Outcomes of implant prosthodontic treatment in older adults.

Older adults are expected to account for an increasingly disproportionate number of individuals needing oral implant prostheses. However, this biotechnology was initially studied for predominantly middle-aged edentulous patients, not elderly people. High rates of success and minimal crestal bone loss have been reported for oral implants mainly in this group. The results of studies at the University of Toronto now clearly support earlier reports that older adults respond to oral implants in the same manner as younger adults, despite their tendency for systemic illness, including osteoporosis. However, unfavourable jawbone quantity and quality, particularly atrophy of the maxilla, impaired implant success. Furthermore, placement of implants in sites that had been edentulous for shorter periods was associated with greater crestal bone loss, a finding that may have implications for younger adults undergoing such treatment. The major decision-making challenge in managing depleted dentitions and complete edentulism in an aging society now lies in differentiating the treatment outcomes, especially patient-mediated assessments (including economic analyses), of the various prosthodontic options available for older adults.

Aged↗
PubMed2002

Implant prosthodontics in medically challenged patients: the University of Toronto experience.

A series of prospective studies started in the mid-1980s at the University of Toronto have provided evidence of the efficacy and effectiveness of implants in the treatment of the fully and partially edentulous patients. These studies have focused primarily on treatment outcomes at the surgical and prosthodontic levels, with an overall failure rate of 7.7% over a 20-year period. Because a considerable proportion of these failures (4.2%) occurred before insertion of the prosthesis, and because osseointegration is essentially a wound-healing process, factors that interfere with healing, including systemic conditions, may contribute to implant failure. This paper reviews studies on the impact of selected systemic conditions, including osteoporosis, cardiovascular diseases, diabetes mellitus, and hypothyroidism, as well as smoking behaviour, on the success or survival of oral implants in patients treated in the Implant Prosthodontic Unit at the University of Toronto.

Cardiovascular Diseases↗
PubMed2002

Implant prosthodontic management of posterior partial edentulism: long-term follow-up of a prospective study.

OBJECTIVE: This paper reports on the long-term outcome of implant-supported posterior-zone prostheses in the first 35 consecutive, partially edentulous patients treated in the Implant Prosthodontic Unit (IPU) at the University of Toronto, Toronto, Ontario. METHODS: A total of 106 Brånemark dental implants were placed in 46 posterior edentulous spans in 35 patients for the management of multiple missing teeth; the patients were followed prospectively. Treatment planning principles involved a minimum of 2 or 3 implants at each edentulous site and scrupulous occlusal prosthodontic designs. RESULTS: The overall survival of posterior implants was 94%. No factors in the patients' history adversely affected implant survival. CONCLUSIONS: This clinical update suggests that the use of Brånemark implants in the rehabilitation of patients who are partially edentulous in the posterior zone is highly effective and that survival of the implants is excellent.

Adult↗
PubMedDate not supplied

A cost minimization analysis of implant treatment in mandibular edentulous patients.

PURPOSE: This study aimed to determine if implant-supported overdentures are a long-term economically efficacious therapy for edentulous patients when compared to fixed osseointegrated prostheses. MATERIALS AND METHODS: Clinical records of 25 patients from two long-term studies (fixed and overdenture) were included in this analysis. A cost minimization analysis from the patient perspective was employed. Direct clinical and time costs incurred over the 9-year period were deflated to 1995 Canadian dollars using the Consumer Price Index. National salary rates by occupation and gender were used to value patients' time, and a sensitivity analysis was carried out to assess the robustness of the results when an equal mean salary rate across treatment groups was assumed. RESULTS: The mean total, clinical, and time costs were significantly higher (Ps .05) for the fixed restoration group (dollars CAD10,748, dollars CAD10,094, and dollars CAD654, respectively) when compared to the overdenture group (dollars CAD3,665, dollars CAD3,343, and dollars CAD322, respectively). The initial, maintenance, and clinical visit costs were also significantly higher (P < or = .05) in the fixed restoration group (dollars CAD7,567, dollars CAD2,527, dollars CAD542, respectively) than in the overdenture group (dollars CAD2,505, dollars CAD830, dollars CAD292, respectively). The sensitivity analysis demonstrated that the time cost for the fixed prosthodontic group (dollars CAD488 vs dollars CAD322) was still significantly higher (P = .002), even after an equal mean salary rate was assumed. CONCLUSION: Overdenture therapy for edentulous patients is a more cost-effective treatment compared to fixed prosthodontic treatment.

Analysis of Variance↗
PubMedDate not supplied

A retrospective study on the treatment outcome of wide-bodied implants.

PURPOSE: This retrospective study documented the 5-year cumulative survival rate (CSR) of 5-mm-diameter wide-bodied implants in posterior jaws as related to identified risk factors and relative host bone site dimensions. MATERIALS AND METHODS: Sixty-four wide-bodied implants placed consecutively in the posterior jaws of 43 patients were matched using several identified risk factors with 64 regular-diameter implants (3.75-mm or 4-mm diameter) placed in the posterior jaws of 25 of the same patients and 14 others. Life table analyses were undertaken to examine the difference in CSR between the groups. Multivariate Cox regression was conducted to assess the relationship between potential risk factors and overall CSR. RESULTS: Ten of the wide-bodied implants failed (CSR 80.9%), while two of the regular-diameter implants failed (CSR 96.8%). The difference between the groups was statistically significant. Multivariate analysis demonstrated a significant predictive relationship between overall CSR and the ratio of implant volume to remaining bone volume. This suggests that relative determinants of critical bone volume to implant dimensions may need to be considered when planning implant surgery. CONCLUSION: Wide-bodied implants placed in the posterior jaw can suffer a significantly elevated risk of implant failure compared to regular-diameter implants. This susceptibility may relate to either implant design or the relative relationship of implant to host bone dimensions.

Adolescent↗
PubMedDate not supplied

A survey of the use of mandibular implant overdentures in 10 countries.

PURPOSE: This preliminary international survey compared provision of implant-retained overdentures to fixed implant-supported prostheses for edentulous mandibles. MATERIALS AND METHODS: Questionnaires based on a 2001 Swedish study were sent to prosthodontists and specialist clinics in nine additional countries. RESULTS: Response rate varied from 53% to 100% in 10 national surveys and should allow careful comparison of results. The relationship between implant overdentures and fixed implant-supported prostheses in treatment of edentulous mandibles varied much; in Sweden, the proportion of overdentures was 12%, whereas it was 93% in The Netherlands. In all countries, the most common reason for choice of the overdenture was reduced cost. In all but two countries, the majority of respondents thought that patients with implant overdentures were equally or more satisfied with overdentures as those with fixed implant-supported prostheses. CONCLUSION: There were great differences among the 10 countries in choice of implant treatment of the edentulous mandible. The relative proportion of mandibular overdentures to fixed prostheses was low in Sweden and Greece and varied from one to two thirds in the other countries, except The Netherlands.

Canada↗
PubMedDate not supplied

Long-term treatment outcomes in edentulous patients with implant-fixed prostheses: the Toronto study.

PURPOSE: The aim of this prospective study was to report long-term treatment outcomes (prosthetic and implant related) of edentulous patients treated with implant-supported fixed prostheses who participated in the first clinical implant study in North America. MATERIALS AND METHODS: Forty-five patients were treated with Brånemark implants supporting a total of 47 fixed prostheses (42 mandibular and 5 maxillary) between 1979 and 1984. All patients were recalled regularly for comprehensive prospective clinical and radiographic assessments. RESULTS: Thirty-one patients (33 prostheses) attended a final recall visit in 2002; 71% of patients had been followed for 20 years (range 18 to 23 years), with overall prosthetic plan and implant outcome success rates of 84% and 87%, respectively. Mean marginal bone loss around the implants after the first year of loading was small (0.05 mm/year), with high individual variations. Poor oral hygiene, smoking history, and implant position appeared to be predictors of marginal bone loss. Prosthetic maintenance was ongoing and included fractured components and replacement of prostheses; the longevity of a fixed prosthesis for this group of patients was 8.39+/-5.30 years. CONCLUSION: This study confirmed the overall long-term treatment outcome success of patients treated with fixed prostheses supported by Brånemark implants. Successful osseointegration with a small mean bone loss was maintained as study patients aged, although prosthetic maintenance was required. The latter consideration should be discussed with all patients seeking such treatment.

Adult↗
PubMedDate not supplied

Long-term treatment outcomes in edentulous patients with implant overdentures: the Toronto study.

PURPOSE: Few long-term studies on overdentures report both implant and prosthodontic outcomes. The aim of this prospective study was to report long-term prosthodontic- and implant-related treatment outcomes of patients treated with design-specific implant-supported overdentures. MATERIALS AND METHODS: Between 1982 and 1992, 45 consecutively treated patients received a total of 47 overdentures (42 mandibular and 5 maxillary) supported by Brånemark implants. Prospective clinical and radiographic data were collected over the observation period; this study presents the most recent treatment outcomes. RESULTS: Thirty patients (mean age 70 years) with 32 prostheses attended the final recall visit, with 67% of patients followed for 15.53 years (range 10 to 19 years). Six implants failed, and the prosthetic plan and implant cumulative survival rates were both in excess of 90%. Mean marginal bone loss around implants after the first year of loading was small (0.05 mm/year), although the individual variation was high. Linear regression analysis of bone loss indicated that gender, bicortical stabilization, bone quality, and healing time were predictors of bone loss for the first year of loading but not for the ensuing years. Prosthetic maintenance included fractured components, denture relining, and replacement of prostheses. On average, the longevity of overdenture prostheses was 12 years, and laboratory relining was necessary every 4 years. CONCLUSION: This study confirmed the long-term outcome success of patients treated with design-specific overdenture prostheses supported by Brånemark implants. However, prosthetic maintenance was required, a fact that should be discussed with patients prior to treatment.

Adult↗
PubMedDate not supplied

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Denture, Overlay↗