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The purpose of this literature review is to present the outcomes of clinical studies on immediate and early loading protocols, identify shortcomings, and suggest a number of questions that still require exploration. English language clinical studies, limited to peer-reviewed journals between 1975 and 2004, were reviewed to identify treatment outcomes with these loading protocols. The data were tabulated from studies reporting on patients treated with fixed and overdenture prostheses. The former included partially edentulous patients treated with single or multi-unit prostheses. Within the limitations of this review, it can be concluded that these treatment protocols are predictable in the anterior mandible, irrespective of implant type, surface topography, and prosthesis design (success rates 90%-100%). Limited evidence for the edentulous maxilla (success rates 90%-100%) and the partially edentulous patient (success rates 93%-100%) are available, underscoring the need for further research. Studies suggest that to achieve predictable results in extraction sites, implant placement should be restricted to sites without a history of periodontal involvement (success rates 61%-100%). A number of questions require further exploration. There is a need to thoroughly investigate clinical outcomes to measure the economic benefit of these protocols and the impact of treatment on a patient's quality of life. Furthermore, more accurate long-term studies reporting on treatment protocols for separate clinical situations are required to allow meaningful comparisons.

Older adults often have bone loss and may be at risk of bone resorption around oral implants.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.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.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.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.

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.

Statement of problem. The frequency of prescription of implant-supported prostheses demands increased scrutiny of systemic health condition on treatment inclusion and exclusion criteria. The risks of an impaired healing response in patients with certain types of cardiovascular diseases (CVD) suggest a possible risk for implant failure in such patients. Purpose. This preliminary study surveyed implant treatment outcome of patients with cardiovascular diseases. Methods. A retrospective analysis of 246 consecutively treated patients was conducted. The patients comprised a CVD interest group of 39 patients, and control subgroups of 98 healthy and 109 patients with a history of other systemic disease. Results. Differences in implant failure rates between the groups were not found to be significant. Though the sample size is small, these results suggest that CVD may not be a risk factor for successful osseointegration. (J Prosthet Dent 1999;81:533-6.)

This article presents a brief review of the methods and techniques to manage the maladaptive edentulous patient. A discussion of the inclusion and exclusion criteria and treatment outcome measures associated with published prospective osseointegrated implant studies are included and specific therapy options are suggested. It is concluded that there is a need for less invasive, less expensive, less complex, and equally effective treatment options such as the implant-supported overdenture for the maladaptive edentulous patient. (J Prosthet Dent 1998;79:60-5.)

Fifty consecutive completely edentulous patients who were unable to wear their complete dentures took part in this prospective longitudinal study. After providing initial optimization treatment of patients' existing prostheses, prosthodontists conducting the study prescribed osseointegrated implant-supported removable overdentures for 45 of the 50 patients. The remaining five underwent ongoing attempts at optimizing their complete dentures. This article details the results of treatment for the 50 patients over a period of three to 13 years.

Successful osseointegration promises a virtual panacea for the edentulous predicament. However, the impact of this technique on specific age groups is far from clear. In an attempt to determine the efficacy and effectiveness of implant-supported prostheses in geriatric patients, the treatment outcomes of elderly patients already included in ongoing clinical trials were assessed. The following preliminary observations were made: (1) being elderly is not a contraindication to long-term implant survival; (2) successful osseointegration can be maintained irrespective of a patient's oral hygiene performance; and (3) diverse prosthesis designs appear feasible.

Throughout the 1980s and '90s, a small core group of clinical scholars played a major and pivotal role in the combined surgical and prosthodontic dissemination of osseointegration scholarship. As professor of oromaxillofacial surgery at the University of Washington, Dr Philip Worthington was one such pioneering educator. His academic leadership was acknowledged via numerous academic honors and tributes, including his recent postretirement recognition as distinguished professor at his university. This invited paper is a personal assessment of the impact of clinical changes ushered in by the osseointegration technique and was recently presented at the University of Washington's unique celebratory tribute to Professor Worthington.

Forty-six patients who had shown chronic maladaptive behavior in using complete dentures were treated with osseointegrated implant-supported prostheses. Forty patients needed mandibular treatment, three patients needed treatment in the maxillae, and three required treatment in both dental arches. At the most recent data collection (4 to 9 years after surgical placement of the implants), the 49 dental arches remained successfully treated with 44 implant-supported fixed partial dentures and five implant-supported overdentures. The efficacy of the osseointegration technique in maladaptive prosthetic patients is demonstrated in this descriptive study.

In this prospective study, 46 edentulous patients who had undergone traditional denture optimization therapy without success were treated with osseointegrated implants according to the surgical protocol described by Dr. P.I. Branemark. Two hundred seventy-four implants were placed in 49 dental arches—43 mandibles and six maxillae. At the time of writing, 4 to 9 years after insertion of the implants, 244 or 89.05% remained osseointegrated. Of the 262 implants in place more than 5 years, 232 or 88.55% were still integrated. The implant success criteria developed in this clinical study endorsed the predictably favorable outcome of the Branemark technique.

To compare the in vitro 3-dimensional (3D) accuracy of fit of laser-scanned Computer Numeric Controlled (CNC)-milled implant titanium frameworks to that of conventional cast frameworks.Nine cast frameworks were fabricated on the mandibular master casts of 9 patients with 5 implants each following the well-established conventional fabrication technique. The frameworks were then laser scanned, and 9 CNC-milled titanium frameworks matching the outline of the conventional frameworks were fabricated. The accuracy of fit of both framework types was measured using a contact-type coordinate measuring machine and a computer program developed specifically for this purpose. Statistical analysis was done by a series of paired ttests.The laser-scanned CNC-milled frameworks showed significantly less distortion along the x-axis (transversal, d(x)) compared with the conventional frameworks (means: 33.7 microm and 49.2 microm, respectively) (P = .011). The titanium frameworks also demonstrated significantly less distortion on the horizontal plane compared with the conventional frameworks (means: 56 microm and 85 microm, respectively) (P = .012). The d(y) (sagittal) and d(z) (vertical) axes and total 3D distortion (square root of dx(2) + dy(2) + dz(2)) showed less distortion overall in the laser-scanned CNC-milled frameworks, but this was not statistically significant (mean: 22.3 vs 35.6 microm, 13.3 vs 59.2 microm, 51 vs 114.1 microm, respectively, for y, z, and 3D distortion).Within the limitations of this study, fabrication of an implant-prosthodontic framework using the CNC milling technique yields a more accurate fit than the currently used cast technique. In vivo studies are needed to investigate the clinical significance of this recorded difference.

Recent studies implicate smoking as a significant factor in the failure of dental implants. The purpose of this long-term retrospective study was to evaluate the survival of Brånemark endosseous dental implants in relation to cigarette smoking.The sample consisted of 464 consecutively treated completely and partially edentulous patients who had a total of 1852 implants placed between 1979 and 1999, and who were part of a surgical/prosthodontic prospective treatment outcomes study. The effect of cigarette smoking on implant survival in relation to the time of implant failure, gender, age, surgeon, date and site of implant placement, implant length and diameter, prosthesis design, and occlusal loading considerations was assessed in bivariate and multivariate survival analyses.The overall implant failure rate was 7.72%. Patients who were smokers at the time of implant surgery had a significantly higher implant failure rate (23.08%) than nonsmokers (13.33%). Multivariate survival analysis showed early implant failure to be significantly associated with smoking at the time of stage 1 surgery and late implant failure to be significantly associated with a positive smoking history. Short implants and implant placement in the maxilla were additional independent risk factors for implant failure.Cigarette smoking should not be an absolute contraindication for implant therapy; however, patients should be informed that they are at a slightly greater risk of implant failure if they smoke during the initial healing phase following implant insertion or if they have a significant smoking history.

The aims of this report are to present the patient-based outcomes and associated clinical costs of an immediate loading protocol for mandibular overdentures in edentulous patients.Two groups of patients were selected. Thirty-five consecutively treated patients received an immediate protocol, while 42 patients treated with a conventional protocol served as a historical control. Patient-based concerns for patients in the immediate group were measured at various stages of treatment with 2 questionnaires: the Denture Satisfaction Scale and the Oral Health Impact Profile. Direct clinical and time costs over a 1-year period were estimated and deflated to 2002 Canadian dollars. Salary rates by occupation, age, and gender were used to evaluate the patients' time costs. Treatment costs were compared between the 2 groups. Additionally, incremental cost-effectiveness ratios for various stages with the immediate protocol were calculated.Significant improvements posttreatment were observed with both the Denture Satisfaction Scale (Wilcoxon signed rank test, P.05) and the Oral Health Impact Profile (Friedman test, P.05). The immediate protocol was associated with higher maintenance costs, with resultant higher total costs (Mann-Whitney U test, P.05). No difference was observed in the time costs associated with the 2 protocols. Within-group analysis of costs at various stages of the immediate protocol suggested that treatment with implant-supported overdentures was more cost-effective than treatment with conventional dentures.This study suggests that implants in 1 jawbone lead to a substantial improvement in perceived oral health status. Furthermore, the immediate loading protocol was not cheaper than a conventional protocol.

The aim of this prospective pilot study was to investigate differences in changes in implant stability and crestal bone height between loaded and unloaded dental implants at 4 months after placement.In the test group, 20 implants were placed in the anterior region of the mandible in 10 patients. They were connected with a Dolder bar within 10 days and placed into function immediately. In the control group, 21 implants were placed in the anterior region of the mandible in a 2-stage procedure in 12 patients. The implants used were TiUnite, with a diameter of 3.75 mm and a minimum length of 10 mm. Resonance frequency analysis was used to measure differences in implant stability, with the implant stability quotient (ISQ) as the unit of measure. An instrument was developed to measure the bone level directly. On a customized abutment, a probe with a stopper measured the distance between the shoulder of the instrument and the bone. Measurements were made on all 4 sides of each implant. Intra- and interexaminer variability showed an agreement that was greater than 99% (kappa0.99) for both sets of measurements.In the early loading group, the mean change in ISQ was -0.08 +/- 0.77 and the mean bone loss from buccal, mesial, distal, and lingual sites was 0.69 +/- 0.15 mm. In the unloaded group, the mean change in ISQ was 1.33 +/- 1.65 and the mean bone loss from buccal, mesial, distal, and lingual sites was 0.53 +/- 0.18 mm. There was no statistically significant difference across the 2 treatment groups. The changes in bone height at buccal and lingual sites were not statistically different from the changes at mesial and distal sites. When gender was included as a factor, the changes in stability and bone loss were statistically smaller among female patients than among male patients.In this preliminary study, early loading did not show an influence on bony crest height and stability in TiUnite implants placed in the anterior mandible during the first 4 months of service.

The aim of this report is to present the implant and clinical outcomes of an immediate-loading protocol of TiUnite implants with mandibular overdentures in edentulous patients.Two groups of edentulous patients were selected. Thirty-five consecutively treated patients received 70 immediately loaded TiUnite implants and 69 Brånemark implants as backup (1 patient received 1 Brånemark implant). The control group was a historical cohort that comprised 42 patients who received 111 Brånemark implants. All overdentures were supported by a resilient bar mechanism. Implant and clinical outcomes, including maintenance events for the first year, were recorded.Implant success rates were in excess of 95% with both protocols. Immediately loaded implants had less bone loss than did implants loaded with the conventional protocol (Mann-Whitney U test; P = .001). Patients in the immediate-loading group required more prosthodontic maintenance, consisting of overdenture remakes and laboratory relining of prostheses (Chi-square test; P.05). Of note, 74% of patients in the immediate-loading group needed a reline to improve the denture seal around the bar housing (Chi-square test; P.05).The favorable implant and bone level outcomes with immediate loading attest to its biologic success. The prosthetic maintenance encountered in the immediate-loading group does not negate the clinical potential of the treatment but rather suggests that the protocol may benefit from modifications.

The study's aim was to report long-term costs in edentulous patients treated with mandibular implant-supported prostheses.Ninety patients were divided into four groups based on the type of implant prosthesis (fixed or overdenture) and treatment year. Records were obtained from dental charts, and an economic analysis from the patient's perspective was conducted. Clinical time associated with various procedures was measured and applied to the four groups. Salary rates by age, occupation, and gender were used to value patients' time. Direct clinical and time costs over 10 years were converted to 2002 Canadian dollars using the Consumer Price Index and discounted at a 3% rate. A sensitivity analysis at an equal salary rate was carried out to test the robustness of the time costs.Initial treatment and maintenance costs over the observation period were significantly higher for fixed compared to overdenture prostheses. A significant improvement in maintenance costs for the first patient group treated with fixed prostheses was observed over the follow-up period. Longer term (15 years) treatment costs for the initial two groups were significantly higher for the fixed group. The sensitivity analysis at an equal salary rate demonstrated the same trend: Time costs were significantly higher for the fixed groups.Long-term treatment costs indicated that the mandibular overdenture was a less expensive treatment compared to the fixed implant prosthesis.

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.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.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.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.

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.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.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.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.

This preliminary international survey compared provision of implant-retained overdentures to fixed implant-supported prostheses for edentulous mandibles.Questionnaires based on a 2001 Swedish study were sent to prosthodontists and specialist clinics in nine additional countries.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.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.

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.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.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.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.

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.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.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 (Por = .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.Overdenture therapy for edentulous patients is a more cost-effective treatment compared to fixed prosthodontic treatment.

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 Branemark 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 Results. A total of 130 patients received 432 Branemark 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. (J Prosthet Dent 2003;89:352-9.)

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.

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.