A 10-year prospective study of ITI dental implants placed in the posterior region. I: Clinical and radiographic results

OBJECTIVES: To evaluate the long-term fixture success rate, crestal bone loss and peri-implant soft tissue parameters around ITI dental implants placed in the posterior region of partially edentulous patients. MATERIAL AND METHODS: A total of 192 ITI dental implants were consecutively placed in premolars and molars of 83 partially edentulous patients admitted for treatment at Geneva Dental School. All implants were restored by means of ceramic-to-metal fused fixed partial dentures and single crowns. Patients were followed as part of a prospective longitudinal study focusing on implant success. Surgical, radiographic and clinical variables were collected at the 1-year recall after implant placement and at the most recent clinical evaluation. RESULTS: The mean observation time was 6 years (range 5-10 years). Four implants failed, yielding a 10-year cumulative survival rate of 97.9%. The mean annual crestal bone loss was -0.04+/-0.2 mm. Hollow-cylinder implants displayed more crestal bone loss (-0.13+/-0.24 mm) than hollow-screw implants (-0.02+/-0.19 mm; P=0.032). Clinical parameters such as age, gender, implant length and bone quality did not affect crestal bone levels. Increase in recession depth (P=0.025) and attachment level (P=0.011) were significantly associated with crestal bone loss. CONCLUSIONS: ITI dental implants placed in the posterior jaw demonstrate excellent long-term clinical success. Hollow-cylinder implants seem to display a higher risk for crestal bone loss. Recession depth and attachment levels appear to be good clinical indicators of peri-implant bone loss.     

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 Br?nemark 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 Br?nemark 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.     

Removable partial denture design involving teeth and implants as an alternative to unsuccessful fixed implant therapy: a case report

Various dental implants have been used, and high success rates have been reported. However, as their uses increase, implant failures have been reported. There are partially edentulous patients with an initial treatment plan of an implant-supported fixed partial denture. At times, one or more strategic implants fail to osseointegrate. In situations where financial, systemic, or local conditions preclude the use of a fixed partial denture, a well constructed removable partial denture can be an excellent treatment alternative. It has been reported that prosthesis support can be improved with the use of osseointegrated dental implants, with improved preservation and maintenance of existing hard and soft tissues around dental implants. This article describes the prosthodontic rehabilitation of a partially edentulous patient by the use of a removable partial denture design involving teeth and implants as an alternative to unsuccessful fixed implant therapy. This treatment option solved a difficult clinical problem derived from the failure of two strategic implants and provided the patient with an esthetic and functional prosthesis.     

An assessment of crown-to-root ratios with short sintered porous-surfaced implants supporting prostheses in partially edentulous patients

PURPOSE: Implant length, implant surface area, and crown-to-root (c/r) ratio and their relationship to crestal bone levels were analyzed in 2 groups of partially edentulous patients treated with sintered porous-surfaced dental implants. MATERIALS AND METHODS: One hundred ninety-nine implants were used to restore 74 partially edentulous patients with fixed prostheses. Implants were categorized according to their length ("short" versus "long") and estimated surface area ("small" versus "large"). "Short" implants had lengths of 5 or 7 mm, while "long" implants were either 9 or 12 mm in length. "Small" implants had estimated surface areas of < or = 600 mm2, while "large" implants had estimated surface areas > 600 mm2. Other data collected included c/r ratio (measured on articulated diagnostic casts), whether or not the implants were splinted, and standardized sequential radiographs. RESULTS: The mean c/r ratio was 1.5 (SD = 0.4; range 0.8 to 3.0), with 78.9% of the implants having a c/r ratio between 1.1 and 2.0. Neither c/r ratio nor estimated implant surface area (small or large) affected steady-state crestal bone levels. However, implant length and whether the implants were splinted did appear to affect bone levels. Long implants had greater crestal bone loss (0.2 mm more) than short implants; splinted implants showed greater crestal bone loss (0.2 mm more) than nonsplinted ones. These differences were statistically significant. DISCUSSION AND CONCLUSIONS: Sintered porous-surfaced implants performed well in short lengths (7 mm or less) in this series of partially edentulous patients. The data suggested that long implants and/or splinting can result in greater crestal bone loss; longer implants and splinted implants appeared to favor greater crestal bone loss in this investigation. These conclusions are, of course, specific to the implants used and would not be relevant to other implant types.     

A cost-effectiveness analysis of implant overdentures

Placement of dental implants may improve the retention and stability of complete dentures in edentulous patients. Treatment costs, however, substantially increase with implant treatment. We therefore performed a stochastic cost-effectiveness analysis, comparing implant-supported over-denture prostheses (4 implants), implant-retained overdentures (2 implants), and complete dentures, from the patient's perspective in Switzerland, to assess whether implant treatment in the mandible represents value for money spent. Twenty patients were included in each treatment group and were followed up for three years. Health outcomes were expressed in Quality-adjusted Prosthesis Years, and dental health care costs and time costs were recorded in year 2000 Swiss Francs (CHF 100 = US dollars 61). The cost per Quality-adjusted Prosthesis Year gained for implant treatment was CHF 9100 (2 implants) and CHF 19,800 (4 implants) over 3 years. Over a ten-year period, these threshold ratios were reduced to CHF 3800 (2 implants) and CHF 7100 (4 implants) per Quality-adjusted Prosthesis Year gained.     

Factors affecting soft tissue around dental implants: a review of the literature

Much of the focus in the early dental implant literature is on the bone-to-titanium interface because a successful osseointegrated implant requires direct bone contact to the implant surface. The research on soft tissue around dental implants has focused on the partially edentulous patient and, in particular, on the maxillary anterior dentition. Few studies have evaluated soft tissue around dental implants in completely edentulous patients over time. This paper reviews the pertinent literature on soft-tissue healing in both partially and completely edentulous dental implant patients from a Medline search of the English peer-reviewed literature from 1980 to 2004.     

Implants in conjunction with removable partial dentures: a literature review

Although the benefits of implant-borne removable prostheses are readily apparent for the fully edentulous patient and have been well documented, there is a paucity of studies concerning the combination of implants with removable partial dentures in partially edentulous patients. The aim of this article is to review the literature regarding implants with removable partial dentures and evaluate the evidence for this clinical approach. A MEDLINE/PubMed search from 1990 to 2006, focusing on the use of implants with removable partial dentures and related features, was supplemented with a hand search to identify relevant peer-reviewed English articles published in dental journals and textbooks on removable partial dentures.     

Immediate placement/immediate load: a single-tooth case study utilizing the ITI dental implant system

For the past 35 years, endosseous dental implants have revolutionized the methods clinicians use to treat edentulous and partially edentulous patients. Initially recommended only to rehabilitate fully edentulous patients utilizing fixed prosthetics, endosseous dental implants were then shown to be effective to treat partial edentulism. Over the last decade, numerous studies have documented successful placement of endosseous dental implants in fresh extraction sites, and methods have been developed to provisionalize both full-arch and single-tooth implant cases at the time of surgery. This article describes the immediate placement/immediate load of a single ITI dental implant.     

Patient expectations of oral implant-retained prostheses in a UK dental hospital

STATEMENT OF PROBLEM: The loss of the natural dentition leads to severe functional impairment in many edentulous adults. A prosthesis retained and supported by osseointegrated dental implants may provide a satisfactory solution for people who have lost all their natural teeth. However, little information is available as to what patients requesting implants expect of implant-retained prostheses. AIM: The aim of this study was to assess the expectations of a group of edentulous patients requesting implant therapy. METHOD: The study included two groups: (1) a group of edentulous adults who requested implant therapy ('implant group'); and (2) an edentulous control group, of similar age and gender distribution as the implant group, receiving conventional complete dentures. Following a clinical and radiographic examination of the patients, data were collected using validated questionnaires. Both groups made a subjective assessment of current dentures. The implant group also completed a questionnaire which assessed expectations of implant-retained prostheses. RESULTS: Baseline satisfaction with current dentures was low in both groups, with the implant group being significantly less satisfied with comfort and stability of their mandibular dentures. Perceived ability of the implant group to chew hard foods was less than the control group. The implant group's expectations of an implant-retained prosthesis were significantly greater than for a conventional denture. CONCLUSION: Careful assessment of patient expectation of implant therapy is essential to determine appropriate treatment need, and to highlight unrealistic expectations.     

Two-year follow-up of a patient with oligodontia treated with implant- and tooth-supported fixed partial dentures: a case report

Dental implants have become an accepted treatment modality for aging patients with either completely or partially edentulous arches. However, growing patients with congenitally missing primary and/or permanent teeth often need dental implant treatment, even before puberty, for optimum functional and/or psychosocial development. From a developmental perspective, dental implants cannot accompany the physiologic differentiation of the alveolar bone because of the difference in anchorage between an osseointegrated dental implant and a tooth in bone. Nevertheless, reports in the literature suggest that dental implants can be used successfully in partially and completely edentulous arches affected by congenital disorders such as ectodermal dysplasia. In this case report, a multidisciplinary team approach, which included an orthodontist, an oral surgeon, and prosthodontists, in the treatment of a patient with oligodontia is discussed. The orthodontic and prosthodontic treatment sequence, growth analysis from age 14 to 18 years, and successful therapy of an implant associated with late failure is presented.     

Crestal Bone Changes at Teeth and Implants in Periodontally Healthy and Periodontally Compromised Patients. A 10‐Year Comparative Case‐Series Study

Background: Limited data exist on the longitudinal crestal bone changes around teeth compared with implants in partially edentulous patients. This study sought to compare the 10‐year radiographic crestal bone changes (bone level [BL]) around teeth and implants in periodontally compromised (PCPs) and periodontally healthy (PHPs) patients. Methods: A total of 120 patients were evaluated for the radiographic crestal BL around dental implants and adjacent teeth at time of implant crown insertion and at the 10‐year follow‐up. Sixty patients had a previous history of periodontitis (PCPs), and the remaining 60 were PHPs. In each category (PCP and PHP), two different implant systems were used. The mean BL change at the implant and at the adjacent tooth at the interproximal area was calculated by subtracting the radiographic crestal BL at the time of crown cementation from the radiographic crestal BL at the 10‐year follow‐up. Results: At 10 years after therapy, the survival rate ranged from 80% to 95% for subgroups for implants, whereas it was 100% for the adjacent teeth. In all eight different patient categories evaluated, teeth demonstrated a significantly more stable radiographic BL compared with adjacent dental implants (teeth BL, 0.44 ± 0.23 mm; implant BL, 2.28 ± 0.72 mm; P <0.05). Radiographic BL changes around teeth seemed not to be influenced by the presence or absence of advanced bone loss (≥3 mm) at the adjacent implants. Conclusions: Natural teeth yielded better long‐term results with respect to survival rate and marginal BL changes compared with dental implants. Moreover, these findings also extend to teeth with an initial reduced periodontal attachment level, provided adequate periodontal treatment and maintenance are performed. As a consequence, the decision of tooth extraction attributable to periodontal reasons in favor of a dental implant should be carefully considered in partially edentulous patients.     

Full-arch restoration of the jaw with fixed ceramo-metal prosthesis: late implant placement

BACKGROUND: The completely edentulous patient has few treatment options in conventional dentistry. When implants are considered, treatment plans range from a 2-implant overdenture to a completely implant-supported prosthesis. Fixed prosthesis is often the preferred selection of the edentulous patient. This study assesses the 5-year cumulative survival rate of implants placed to support full-arch fixed restoration. METHODS: During 1990 to 1995, 171 implants were placed in 22 completely edentulous jaws of 20 patients. All patients were discharged wearing immediate dentures. The implants were analyzed as to the number of implants per jaw, implant location, length, and diameter. RESULTS: The 5-year cumulative survival rate was 89.9%. The mean number of implants per jaw was 7.7 for the maxilla and 8 for the mandible. In the maxilla, the preferred implant locations were the canines, centrals, laterals, and first premolars; in the mandible, they were the canines, laterals, and first molars. The mean implant length was 14.2 mm for the mandible and 13.2 mm for the maxilla. The mean implant diameter was 3.6 mm for the maxilla and 3.8 for the mandible. CONCLUSIONS: The results of the present study indicate that fixed full-arch ceramo-metal restorations can be a predictable implant treatment modality for the edentulous patient.     

无抗生素预防感染的牙种植治疗效果

目的：探讨无抗生素预防的牙种植效果，为临床提供理论依据。方法：将牙种植患者154名随机分为两组，对照组83名（196枚种植体）给予口服青霉素V（PC－V）预防处理，实验组71名（167枚种植种）术前、术后均不给予抗生素治疗。结果：经统计学分析，两组之间术后感染率无显著性差异，上颌骨与下颌骨种植体的存留率也无显著性差异。结论：在常规牙种植外科应用抗生素预防感染是无意义的。     

Basic surgical principles with ITI implants

The basic surgical principles governing the placement of ITI implants are based on research-oriented developments in harmony with evidence-based and outcome-oriented clinical procedures. In the past 15 years, the range of implant indications has been significantly widened, and partially edentulous patients clearly represent the majority of patients seeking treatment with dental implants today. An important aspect of the successful rehabilitation of patients with ITI implants is the careful selection of implant candidates with respect to systemic and local risk factors. These factors are presented based on current knowledge. Today, solid-screw implants in various screw dimensions and neck configurations comprise the ITI Dental Implant System. These different implant types are necessary to handle the full range of implant indications, in particular in partially edentulous patients. The main clinical factors are presented for the selection of the appropriate implant type, length and diameter. These implants are utilized both in a non-submerged and in a submerged approach. The main goal of surgical therapy is low trauma and the least demanding surgical procedure for patient and clinician to optimize the cost-effectiveness of implant therapy. Hence, a non-submerged approach is preferred in all sites without esthetic priority, such as in fully edentulous patients or in posterior sites of partially edentulous patients. These indications clearly represent the majority of implant patients. In esthetic sites, a submerged approach is utilized to satisfy the specific esthetic demands. The possibility to successfully utilize short implants (6 and 8 mm) and a reduced healing period of 3 months are further advantages of ITI implants due to favorable properties of the rough TPS surface. With the introduction of the microrough SLA surface, a reduction of the healing period to 6 weeks facilitates further progress towards simplification of implant therapy. In summary, the ITI Dental Implant System represents a scientifically well-documented, complete implant system for the treatment of fully and partially edentulous patients, offering straightforward surgical concepts based on predictable treatment outcome and excellent cost-effectiveness.     

Use of dental implants to improve unfavorable removable partial denture design

This study aimed to determine whether the use of a limited number of dental implants, with no rigid connection between implants and teeth and as few as possible prosthetic element requirements, is a viable solution for improving unfavorable removable partial dentures (RPD) design. Fifteen partially edentulous patients with an unfavorable number and distribution of abutment teeth were treated, each with a limited number of implants, from 1997 to 2004, resulting in an improved RPD design. Implant survival rate was 100%, and prosthetic complications were minor. All patients reported great satisfaction with the partial dentures and good chewing efficiency. The results indicate that the use of dental implants to improve unfavorable RPD design is a viable and cost-effective treatment modality.     

A 10-year prospective study of ITI dental implants placed in the posterior region. II: Influence of the crown-to-implant ratio and different prosthetic treatment modalities on crestal bone loss

OBJECTIVE: To evaluate the influence of the crown-to-implant ratio (C/I) ratio and different implant prosthetic treatment modalities on crestal bone loss around dental implants placed in the posterior region. MATERIAL AND METHODS: A total of 192 ITI dental implants were consecutively placed in premolars and molars of 83 partially edentulous patients. All implants were restored by means of ceramic-to-metal fused fixed partial dentures or a single crown. Patients were followed as part of a prospective longitudinal study focusing on implant success. Surgical, radiographic and clinical variables were collected at the 1-year recall after implant placement and at the most recent clinical evaluation. Radiographic parameters were evaluated on periapical radiographs taken with a standardized long-cone paralleling technique. Implant restorations were divided into three groups according to their respective clinical C/I ratios: (a) 0-0.99, (b) 1-1.99 and (c) >or=2. RESULTS: The mean clinical C/I ratio was 1.77+/-0.56 mm. A total of 51 implants (26.5%) showed a clinical C/I ratio equal to or greater than 2. In this group, three implants failed, giving a cumulative survival rate of 94.1%. Crestal bone loss was -0.34+/-0.27 mm in group a, -0.03+/-0.15 mm in group b and -0.02+/-0.26 mm in group c. Differences among groups were statistically significant (P=0.009). Mode of retention, splinting or presence of cantilever extensions did not have an effect on crestal bone loss around ITI dental implants. CONCLUSIONS: Implant restorations with C/I ratios between 2 and 3 may be successfully used in the posterior areas of the jaw.     

Immediate loading of 190 endosseous dental implants: a prospective observational study of 40 patient treatments with up to 2-year data

PURPOSE: The present study was undertaken to determine the feasibility of using primary stability as a predictor of implant success in patients whose implants were immediately loaded. MATERIALS AND METHODS: The study included 40 patients, in whom a total of 190 implants were placed, 102 in maxillary sites and 88 in mandibular sites. All were loaded within 72 hours of placement. Sixteen patients were completely edentulous in the mandible and/or the maxilla. The remaining 24, who were partially edentulous, received fixed partial dentures or single-implant restorations. All of the definitive implant restorations were screw retained. The criterion for loading was clinical judgment of primary stability, verified by a "screw test." Impressions were made after implant placement to facilitate the fabrication of a laboratory-made heat-processed provisional restoration from acrylic resin. Following a 4-month period for osseointegration and soft tissue healing, definitive fixed prostheses were fabricated. RESULTS: There were no surgical complications. After 1 to 2 years, all 190 implants had survived and were considered 100% successful, as determined by independent testing of mobility and radiographic evidence of osseointegration. In 4 patients, fracture of the provisional restoration occurred during the healing period. DISCUSSION: Clinical research has shown that immediate loading is a viable treatment modality. The favorable success rate reported in this study for rough-surfaced implants suggests that adherence to a protocol, an important parameter of which is primary stability above 32 Ncm, can lead to osseointegration. CONCLUSION: The results of this limited investigation suggest that patients who are partially or completely edentulous may be immediately restored with implants and fixed provisional restorations, provided that the dental implants are adequately stable immediately after their surgical placement. This alternative therapeutic approach did not appear to affect the up-to-2-year survival of the implants in this patient population.     

Spline implant prospective multicenter study: interim report on prosthetic screw stability in partially edentulous patients

Loosening of implant abutment and prosthesis screws during functional loading is an industrywide phenomenon that is especially well documented with the external hexagon implant connection. Although numerous efforts to reduce or eliminate screw loosening have been attempted, the problem still persists, especially with implant restorations in the partially edentulous patient. In 1992, the spline was developed as an alternative to the external hexagon implant-abutment connection. A prospective multicenter study was begun in 1996 to evaluate the abutment and prosthesis screw joint stability of Spline® dental implants (Centerpulse Dental Division, Carlsbad, California) over 5 years of post-loading clinical follow-up. From October 1996 to December 2000, 73 partially edentulous patients were consecutively treated with 113 Spline implants placed in two private dental practices. Three patients with 1 implant each withdrew from the study for various reasons; of the remaining 110 implants in 70 patients who continued in the study, 82% (n = 90) were placed between 1997 and 1998. No cases of abutment or prosthesis screw loosening occurred with up to 54 months (mean = 38.95 mo; range, 3–54 mo; mode, 20 mo) of post-loading clinical follow-up. These interim findings of the ongoing study suggest that Spline dental implants may provide a stable prosthetic connection in partially edentulous cases during short-term clinical follow-up.
CLINICAL SIGNIFICANCE
If left untreated, implant-related screw loosening can potentially lead to bone loss, component breakage, and even implant failure. The results of this study suggest that the Spline implant may provide predictable screw joint stability in partially edentulous cases.     

Passive tactile sensibility in edentulous subjects treated with dental implants: a pilot study

STATEMENT OF PROBLEM: Edentulous patients treated with implant-supported prostheses have shown increased passive tactile sensibility compared with those using conventional complete dentures. This is thought to be due to the close mechanical coupling between the implant and bone via the osseointegrated interface, yet the phenomenon has received little attention. PURPOSE: The purpose of this study was to measure passive tactile sensibility in a group of edentulous subjects treated with dental implants, and to relate the measured sensibility to a range of factors thought to be of possible relevance, namely, patient age, gender, time since implant placement, implant length, and implant separation.MATERIAL AND METHODS: Twenty edentulous subjects successfully treated with 2 or more Nobel Biocare dental implants in the anterior mandible were studied. The inclusion criteria were : (1) age of less than 50 years, (2) a period of at least 12 months since implant placement, (3) implant length of at least 10 mm and of standard diameter (excluding narrow and wide platform designs), and (4) implant separation of at least 18 mm. Using a computer-controlled custom-made device, pushing forces (2.1, 2.4, 2.7, and 3.0 N/s) were applied directly and perpendicular to the long axes of the implant abutments until the subjects felt the first sensation of pressure. The magnitude of these forces was measured with an integral transducer. The applied force had a ramped staircase pattern, and force application rates were varied between 2.1 and 3.0 N/s. Multilevel modeling was used to analyze the collected data (alpha=.05). RESULTS: The threshold values of passive tactile sensibility ranged between 3.1 and 15.7 N (mean 10.9; SD 3.9). Analysis failed to show any significant association between passive tactile sensibility and the variables studied. CONCLUSION: Within the limitations of this study, which included a small sample size, no relationship was found between passive tactile sensibility associated with long-standing implants and any of the variables studied (age, gender, time since implant placement, implant length, and implant separation).