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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.

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 Branemark System) implants (Nobel Biocare AB, Goteborg, 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 computer-assisted measurement technique for measuring bone levels proximal (mesial and distal) to oral implants imaged on standardized intraoral radiographs offers promise for accuracy and reliability. There were no differences between bone measurements made directly from bone proximal to implants placed in a dry mandible and those resulting from the computer-assisted measurement technique. In addition, there were no differences between measurements made of bone proximal to oral implants in vivo using the microscope and the computer techniques. The computer technique had a low intra- and inter-operator variability, and operators found fewer “unreadable” sites compared to the microscope technique. The computer-assisted measurement of bone levels proximal to oral implants on standardized intraoral radiographs offers accuracy and reliability.

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.)

Maximal occlusal force and oral tactile sensibility were recorded in 21 edentulous patients wearing maxillary complete dentures and mandibular fixed prostheses supported by Branemark implants. Bite force was measured with a miniature force transducer between antagonistic molars and premolars, and the passive tactile sensibility of the fixtures was recorded in the horizontal and vertical directions with spring balances. The active tactile sensibility was tested using steel foils (100 to 10 microns). The range of maximal occlusal force recorded was from 35 to 330N with highest values observed on the second premolars (mean 143N). Significantly lower forces were found on molars and first premolars (p < 0.01). The detection threshold of minimal pressure was about 330 g in the horizontal, and 388 g in the vertical direction. This difference was not statistically significant. The average number of incorrect assessments when testing steel foils was 16.6 errors, out of 100 recordings. Similar results when using these 3 test modalities had been found on overdentures supported by two mandibular implants and occluding with maxillary complete dentures. The results of this study suggest that mandibular implants supporting fixed prostheses are not likely to improve oral tactile sensibility and maximal occlusal force in the presence of maxillary complete dentures.

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.

Treatment choice and effectiveness in prosthodontics has largely depended on educated anecdote and asseveration. Still, this approach has to a very large extent enabled dentists to enrich the quality of their patients9 lives. However, the trade-off between the need for prosthetic intervention per se and the biologic price inherent in certain therapeutic endeavors has demanded strict concerns regarding clinical decision making and treatment outcomes. The technique of implant prosthodontics is certainly one that has focussed such concerns, particularly since the concept of osseointegration was introduced to North American dentists at the 1982 Toronto Conference. Clinical research and opinion in this area have elicited both clinical euphoria and polarization vis-a-vis newer possibilities for resolving the predicaments of partial or complete edentulism. The past decade has witnessed clinical trials, as well as highly relevant exemplary reports, on the application of the osseointegration technique. It is now necessary to compare the merits of implant prosthodontics to traditional therapies, and to determine those criteria which comprise optimal functional and aesthetic restoration, with minimal risk of morbidity, along with cost concerns. This paper seeks to provide a systematic and rational basis for the identification of such criteria.

This prospective study at the University of Toronto reports the 5-10-year results of treatment of edentulous patients with osseointegrated implant supported bridges. It comprised 46 consecutively treated patients, chosen because optimisation of traditional prostheses was not successful and because they were in sufficiently good health to allow minor out-patient surgery. Two hundred and seventy-four implants were surgically placed in 49 arches (three patients were treated in both arches) between October 1979 and March 1984. At the end of the 5-10-year observation period, 242 (88.32%) of the implants remained osseointegrated and 233 or 85.04% of these implants were used to support 43 fixed bridges and five overdentures. Nine implants, though osseointegrated, were not exposed and were not used to support the prostheses. Forty-eight of the 49 arches continue to be successfully restored with implant retained prostheses

Because of the proliferation of implant systems, a set of criteria for implant success based on scientific investigations is essential. A review of the literature and the analysis of the results indicate that six criteria are supported as valid for determining the clinical success of endosseous dental implants. These criteria are proposed for use in clinical investigation on implants.

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.