Survival of Dental Implants Placed in Grafted and Nongrafted Bone: A Retrospective Study in a University Setting.

PURPOSE: To compare dental implant survival rates when placed in native bone and grafted sites. Additionally, risk factors associated with dental implant loss were identified. This study was based on the hypothesis that bone grafting has no effect on implant survival rates. MATERIALS AND METHODS: A retrospective chart review was conducted for patients receiving dental implants at the University of Texas, School of Dentistry from 1985 to 2012. Exclusion criteria included patients with genetic diseases, radiation and chemotherapy, or an age less than 18 years. To avoid misclassification bias, implants were excluded if bone grafts were only done at the same time of placement. Data on age, sex, tobacco use, diabetes, osteoporosis, anatomical location of the implant, implant length and width, bone graft, and professional maintenance were collected for analysis. RESULTS: A total of 1,222 patients with 2,729 implants were included. The cumulative survival rates at 5 and 10 years were 92% and 87% for implants placed in native bone and 90% and 79% for implants placed in grafted bone, respectively. The results from multivariate analysis (Cox regression) indicated no significant difference in survival between the two groups; having maintenance therapy after implant placement reduced the failure rate by 80% (P < .001), and using tobacco increased the failure rate by 2.6-fold (P = .001). CONCLUSION: There was no difference in the dental implant survival rate when implants were placed in native bone or bone-grafted sites. Smoking and lack of professional maintenance were significantly related to increased implant loss.

Indications and Frequency for the Use of Cone Beam Computed Tomography for Implant Treatment Planning in a Specialty Clinic.

PURPOSE: To analyze the indications and frequency for three-dimensional (3D) imaging for implant treatment planning in a pool of patients referred to a specialty clinic over a 3-year period. MATERIALS AND METHODS: All patients who received dental implants between 2008 and 2010 at the Department of Oral Surgery and Stomatology at the University of Bern were included in the study. The influence of age, gender, and time of treatment (2008 to 2010) on the frequency of use of two-dimensional (2D) radiographic imaging modalities alone or in combination with 3D cone beam computed tomography (CBCT) scans was analyzed. Furthermore, the influence of the indication, location, and need for bone augmentation on the frequency of use of 2D imaging modalities alone or in combination with CBCT was evaluated. RESULTS: In all, 1,568 patients (792 women and 776 men) received 2,279 implants. Overall, 633 patients (40.4%) were analyzed with 2D imaging procedures alone. CBCT was performed in 935 patients (59.6%). There was a statistically significant increase in CBCT between 2008 and 2010. Patients older than 55 years received a CBCT scan in addition to 2D radiographic imaging statistically significantly more often. Additional 3D imaging was most frequently performed in the posterior maxilla, whereas 2D radiographs alone exhibited the highest frequency in the anterior mandible. The combination of 2D with CBCT was used predominantly for implant placement with simultaneous or staged guided bone regeneration or sinus elevation. CONCLUSION: Based on these findings from a specialty clinic, the use of additional CBCT imaging for implant treatment planning is influenced by the indication, location, local anatomy (including the need for bone augmentation), and the age of the patient.

Removal Rates of Dental Implants Placed in Conjunction With Autologous Bone and Xenogeneic and Synthetic Alloplastic Materials in Finland Between 1994 and 2012.

PURPOSE: This study aimed to assess the use of bone augmentation materials in Finland from 1994 to 2012 by assessing removal rates of implants placed in combination with autologous bone, xenogeneic grafts, and synthetic alloplastic materials. MATERIALS AND METHODS: The National Institute for Health and Welfare in Finland granted permission to access raw data of the Finnish Dental Implant Register for implant augmentation materials and removal rates of implants placed in augmented sites from April 1994 to April 2012. RESULTS: A total of 198,538 implants were placed in Finland between 1994 and 2012 in 110,543 operations. A total of 3318 (1.7%) of the placed implants were removed during the observation period. Augmentations were performed on 20,812 (18.8%) operations during 1994-2012. The removal rates of implants placed at sites augmented with autologous bone were 2.31%, xenogeneic materials 0.91%, and synthetic alloplastic materials 2.80%. The removal rate was 1.87% when no augmentation material was used. CONCLUSIONS: The placement of dental implants in conjunction with bone augmentation materials is predictable with a low complication rate.

Effectiveness of implant therapy analyzed in a Swedish population: early and late implant loss.

Treatment outcomes in implant dentistry have been mainly assessed as implant survival rates in small, selected patient groups of specialist or university clinical settings. This study reports on loss of dental implants assessed in a large and randomly selected patient sample. The results were aimed at representing evaluation of effectiveness of implant dentistry. Using the national data register of the Swedish Social Insurance Agency, 4,716 patients were randomly selected. All had been provided with implant-supported restorative therapy in 2003. Patient files of 2,765 patients (11,311 implants) were collected from more than 800 clinicians. Information on patients, treatment procedures, and outcomes related to the implant-supported restorative therapy was extracted from the files. In total, 596 of the 2,765 subjects, provided with 2,367 implants, attended a clinical examination 9 y after therapy. Implant loss that occurred prior to connection of the supraconstruction was scored as an early implant loss, while later occurring loss was considered late implant loss. Early implant loss occurred in 4.4% of patients (1.4% of implants), while 4.2% of the patients who were examined 9 y after therapy presented with late implant loss (2.0% of implants). Overall, 7.6% of the patients had lost at least 1 implant. Multilevel analysis revealed higher odds ratios for early implant loss among smokers and patients with an initial diagnosis of periodontitis. Implants shorter than 10 mm and representing certain brands also showed higher odds ratios for early implant loss. Implant brand also influenced late implant loss. Implant loss is not an uncommon event, and patient and implant characteristics influence outcomes (ClinicalTrials.gov NCT01825772).

Assessment of short dental implants restored with single-unit nonsplinted restorations.

OBJECTIVES: To investigate the survival rate of short (≤9 mm) implants restored with single-unit, nonsplinted crowns after an average follow-up of 37 months (21-94 months). MATERIALS AND METHODS: Two hundred and twenty-one implants placed in 168 patients (74 men, 94 women, aged 34-87 years, mean = 61 years). Implant lengths were 6 (n = 16), 8 (n = 166), 8.5 (n = 2), or 9 mm (n = 34). The implant diameters ranged from 3.7 to 5.6 mm. Implants were placed in the maxillary (n = 44) and mandibular arches (n = 176). RESULTS: Survival rate was 94.1% (maxilla [88.6%] and mandible [96.0%]) and 12 early failures (first 4 months) and 1 late failure (4.5 years in the maxillary molar region) observed. Of the 12 early failures, 4 were in the maxilla (2 premolars and 2 molars) and 8 in the mandible (2 premolars and 6 molars). The early failures were 11 implants of 8 mm long and a 9-mm implant. Smoking cigarettes, diabetes mellitus, and bone augmentation procedures were not associated with implant failure significantly (P > 0.05). CONCLUSIONS: Survival rate of short implants restored with single-unit, nonsplinted restorations over an average period of 37 months was favorable and comparable with longer implants.

Implant diameter and length influence on survival: interim results during the first 2 years of function of implants by a single manufacturer.

OBJECTIVES: The aim of the present study was to evaluate the influence of implant length and diameter on implant survival. METHODS: A retrospective cohort of 787 consecutive patients from 2 private practices between the years 2008 and 2011 had been evaluated. Patient demographics, site and implant characteristics, and time of follow-up were recorded from the medical files. RESULTS: Overall, 3043 implants were investigated. Overall survival rate was 98.7% with 39 implant failures recorded. Survival rates for narrow- (<3.75 mm), regular- (3.75-5 mm), and wide- (>5 mm) diameter implants were 98.2%, 98.7%, and 98.5%, respectively (P = 0.89). Survival rates of short (<10 mm) and regular (10 mm and above) implants were 97% and 98.7%, respectively (P = 0.22). CONCLUSIONS: Implant length and diameter were not found to be significant factors affecting implant survival during the first 2 years of function in the present investigation of this specific implant system by a single manufacturer. Further long-term follow-up studies are warranted because 2-years are only interim short-term results when dealing with dental implants.

An evidence-based concept of implant dentistry. Utilization of short and narrow platform implants.

As a profession, we must remember that tooth replacement is not a luxury; it is often a necessity for health reasons. Although bone augmentation and CBCT and expensive surgical guides are often indicated for complex cases, they are being overused. Simple or straightforward implant cases, when there is sufficient natural bone for narrow or shorter implant, can be predictable performed by well-trained GPs and other trained specialists. Complex cases requiring bone augmentation and other complexities as described herein, should be referred to a surgical specialist. Implant courses and curricula have to be based on the level of complexity of implant surgery that each clinician wishes to provide to his or her patients. Using a "logical approach" to implant dentistry keeps cases simple or straightforward, and more accessible to patients by the correct use of narrow and shorter implants.

A retrospective analysis of replacing dental implants in previously failed sites.

OBJECTIVE: Overall first-year failure rate for dental implants may reach 3%-8% as the result of various complications. Accordingly, reimplantation accounts for an ever-growing portion of clinic's practice. The purpose of the present study was to evaluate the survival rate of dental implants that were performed in sites where failed implants were previously removed and to evaluate the factors affecting outcome. STUDY DESIGN: Three certified oral and maxillofacial surgeons inserted 144 implant replacement in previously failed sites in 144 patients (1994-2009). Clinical and epidemiologic data were collected retrospectively and analyzed regarding survival rates. RESULTS: Survival rate of the implants replacing previously failed ones was 93% (133/144). A third placement in the same site was performed in 7 of 11 patients with a survival rate of 85% (6/7) up to the last follow-up. No correlations were found between replaced implant failures with any of the parameters examined. CONCLUSIONS: Within the limits of the present study, it can be concluded that a previous implant failure should not discourage practitioners from a second or even a third attempt.

Implants in the severely resorbed mandibles: whether or not to augment? What is the clinician's preference?

INTRODUCTION: The aim of this study is to inventory in the Netherlands which therapy is the clinician's first choice when restoring the edentulous mandible. MATERIAL AND METHODS: A questionnaire was sent to all Dutch Oral and Maxillofacial surgeons. As part of this, the surgeons were invited to treat five virtual edentulous patients, differing only in mandibular residual height. RESULTS: In cases of a sufficient residual height of 15 mm, all surgeons were in favour to insert solely two implants to anchor an overdenture. In case of a residual height of 12 mm, 10% of the surgeons choose for an augmentation procedure. If a patient was presented with a mandibular height of 10 mm, already 40% of the OMF surgeons executed an augmentation procedure. Most (80%) surgeons prefer the (anterior) iliac crest as donor site. The choice of 'whether or not to augment' was not influenced by the surgeon's age; however, the hospital, where he was trained, did. Surgeons trained in Groningen were more in favour of installing short implants in mandibles with reduced vertical height. DISCUSSION: As the option overdenture supported on two interforaminal implants is reimbursed by the Dutch health assurance, this treatment modality is very popular in the Netherlands. From a point of costs and to minimize bypass comorbidity, surgeons should be more reluctant in executing augmentation procedures to restore the resorbed edentulous mandible as it is dated in literature that also in mandibles with a residual height of 10 mm or less, solely placing implants, thus without an augmentation procedure in advance, is a reliable treatment option.

Survival rate for implants placed in the posterior maxilla with and without sinus augmentation: a comparative cohort study.

BACKGROUND: The reduced bone height and proximity of the maxillary sinus are the most common limitations for placement of dental implants in the posterior maxilla. Reconstruction of the atrophic posterior maxilla can be performed with a sinus augmentation procedure. The aim of this cohort study is to compare the survival rate of implants placed in augmented sinus to implants placed in native bone in the posterior maxilla. METHODS: This study was designed as a prospective cohort study and included consecutively treated patients. Patients who required the sinus augmentation (test group) were treated according to the two-stage technique. Patients were scheduled for follow-up evaluation at 3, 6, and 12 months after implant placement and then every 6 months for ≤ 6 years. RESULTS: One hundred and five patients with 393 implants were enrolled in the study. Two hundred and one implants were placed after preliminary sinus floor grafting in 41 patients. The control group contained 64 patients with 192 implants that were placed in pristine bone of the posterior maxilla. The cumulative implant survival rates were 86.1% and 96.4%, respectively. The difference between the two groups was highly significant (P <0.005). CONCLUSIONS: These findings show that implants placed in augmented sinuses had a lower survival rate compared to implants placed in pristine bone. All the implant failures in the augmented sinuses occurred before the prosthetic rehabilitation. Moreover, it should be considered that most of the failures were observed in few patients, thus suggesting cluster behavior.

Short-term clinical retrospective study of implants in geriatric patients older than 70 years.

OBJECTIVES: The objectives of this study were to analyze the presence of systemic diseases, associated complications, and other problems occurring after loading of an implanted prosthesis, and to evaluate the amount of bone resorption occurring at the apex of alveolar bone. Therefore, this study analyzed these effects on dental implants in elderly patients with systemic diseases. STUDY DESIGN: In total, 35 patients over the age of 70 years who had been operated on at Seoul National University Bundang Hospital (Seongnam, Korea) between June 2003 and December 2006 were included. According to the types of additional surgical procedures, implant site, implant prosthesis, and systemic diseases, statistical comparisons were made of peri-implant bone resorption at last follow-up. RESULTS: Following the completion of prosthodontic treatment, after a mean period of 32.7 months, the mean peri-implant bone resorption was 0.27 mm, and the peri-implant bone resorption was not significantly related to the type of upper prosthesis (P = .383), the surgical procedures accompanying placement (P = .933), or the presence/absence of systemic disease (P = .484). CONCLUSIONS: According to this analysis, implant therapy in geriatric patients with controlled systemic disease should not be considered to be of particularly high risk.

Evaluation of the effectiveness of dental implant therapy in a practice-based network (FOCUS).

PURPOSE: Evaluations of multicenter clinical trials are needed to determine the effectiveness of care in routine implant therapy in clinical practice. MATERIALS AND METHODS: Ninety-two clinicians in 75 clinics in 13 countries recruited five subjects per clinic who were in need of a minimum of two dental implants to restore a partially edentulous quadrant and were followed for a minimum of 1 year after loading. A centralized Internet-based case report form was developed to coordinate data recording. Data entry was done by each clinic, with follow-up source verification. RESULTS: The study recruited 549 subjects in 101 clinics with 1,893 implants placed. Three hundred forty subjects completed the 1-year recall (gender distribution of 56% female, 44% male; mean age of 57 years with a range of 18 to 84 years). In all, 1,246 dental implants were followed; a majority of subjects had two to four implants. Twenty-eight percent of subjects received osseous grafting prior to or coincident with implant placement. In the maxilla, 779 (63%) implants were placed, 256 in the anterior and 523 in the posterior; in the mandible, 467 implants were placed, 85 in the anterior and 382 in the posterior arch. The median edentulous period prior to implant placement was 24 months (range, 0 to 480 months); 46% of all patients received implants within 12 months of tooth loss. At 1 year after prosthesis insertion, 15 subjects had lost a total of 17 implants, for a cumulative implant survival rate of 98.6%. Chi-square and Fisher exact tests indicated a higher risk of implant loss at sites with advanced resorption and for wider-diameter implants (5-mm tapered body). There was no statistical relationship with implant loss relative to implant length or anatomic location within the oral cavity. CONCLUSIONS: The outcomes support the need for ongoing involvement of clinicians in routine practice assessments of patient-based outcomes of implant therapy.

Implant survival rates in a condensed surgical and prosthetic training program for general practitioners in dental implants.

PURPOSE: The aim of this study was to evaluate the survival rates for surgical placement of dental implants in the Implant Dentistry Study Consortium (IDSC), a training program for general dentists in the UAE. MATERIALS: The records of the program were reviewed, and all implants placed were evaluated, and the survival and failures were identified. These records were compared with those from an experienced prosthodontist who has been trained in both the surgical and restorative phases of implant dentistry. Descriptive statistics and Kaplan-Meier survival curves were calculated. The Kaplan-Meier statistics were compared using the log-rank test. RESULTS: The characteristics of the population of the IDSC and the prosthodontist were similar. During the study interval, the prosthodontist had 299 implants in 145 subjects and IDSC with 217 implants in 104 subjects placed. The survival rates were 96% for the experienced prosthodontist and 93.5% for IDSC dentists. The Kaplan-Meier curves were not statistically different from each other, P > 0.05. CONCLUSION: A closely supervised training program in dental implantology of 4 sessions, 3 day each, can provide successful surgical experiences for the program participants.

Implant restoration of partially edentulous ridges: a review of 121 Nigerian patients.

OBJECTIVE: Because of increasing health awareness, many Nigerian patients are demanding that their lost tooth/teeth be replaced with dental implants. This study reports the pattern and distribution of implant replacement of lost tooth/teeth in a private dental practice in Lagos, Nigeria. METHODS: A retrospective review of implant replacement of lost tooth/teeth over a period of 6 years at Schubbs Private Dental Clinic, Lagos, was carried out. Data analysis included age, sex, occupation, habits and medical condition of patients, augmentation procedure, technique of implant placement (immediate vs conventional loading) tooth/teeth replaced, and follow-up period. RESULTS: A total of 227 implants (Bicon, Boston, MA) with complete superstructure were placed in 121 patients(males = 68, females = 53; age range: 15-74 years). Majority of the patients were of high socioeconomic class. Ten (8.3%) patients had immediate implants and 111 (91.7%) undergone 2-stage implant procedures. The highest number (39.2%) of implants was placed in the molar region, and the replacement of the canines was the lowest (3.1%). Success rate over a period of 6 years was 96%. Of the 9 (4%) implants that failed, 2 were repeated and remained functional till date. CONCLUSIONS: Dental implant therapy as a means of tooth replacement is gaining popularity among Nigerian social upper class. Success rate in this series is comparable with previous reports from Europe and America.

A retrospective analysis of patients referred for implant placement to a specialty clinic: indications, surgical procedures, and early failures.

PURPOSE: This retrospective study analyzed the pool of patients referred for treatment with dental implants over a 3-year period in a referral specialty clinic. MATERIALS AND METHODS: All patients receiving dental implants between 2002 and 2004 in the Department of Oral Surgery and Stomatology, University of Bern, were included in this retrospective study. Patients were analyzed according to age, gender, indications for implant therapy, location of implants, and type and length of implants placed. A cumulative logistic regression analysis was performed to identify and analyze potential risk factors for complications or failures. RESULTS: A total of 1,206 patients received 1,817 dental implants. The group comprised 573 men and 633 women with a mean age of 55.2 years. Almost 60% of patients were age 50 or older. The most frequent indication for implant therapy was single-tooth replacement in the maxilla (522 implants or 28.7%). A total of 726 implants (40%) were inserted in the esthetically demanding region of the anterior maxilla. For 939 implants (51.7%), additional bone-augmentation procedures were required. Of these, ridge augmentation with guided bone regeneration was performed more frequently than sinus grafting. Thirteen complications leading to early failures were recorded, resulting in an early failure rate of 0.7%. The regression analysis failed to identify statistically significant failure etiologies for the variables assessed. CONCLUSIONS: From this study it can be concluded that patients referred to a specialty clinic for implant placement were more likely to be partially edentulous and over 50 years old. Single-tooth replacement was the most frequent indication (> 50%). Similarly, additional bone augmentation was indicated in more than 50% of cases. Adhering to strict patient selection criteria and a standardized surgical protocol, an early failure rate of 0.7% was experienced in this study population.

Report of 1633 implants in 814 augmented sinus areas in function for up to 180 months.

PURPOSE: The long-term success of implants functioning in sinuses augmented with a variety of materials were evaluated in 2 private practices. MATERIALS: Treatment outcomes of 1814 augmented sinuses, and subsequent placement of 1633 implants into 763 augmented sinuses, were assessed through clinical and radiographic examinations in 2 private practices. Statistical analysis was carried out utilizing the analysis of variance method and step-wise linear regression at P < 0.001. RESULTS: Eight hundred fourteen sinus augmentation procedures were performed. Eight hundred six sinus augmentation procedures were deemed successful (99.0%), as defined by implants functioning successfully in the augmented sinus areas. A variety of augmentation materials were utilized to effect sinus augmentation. Of the 1633 implants placed in augmented sinuses, 1613 were functioning successfully, yielding an accumulate success rate and function of 98.1%. The mean implant time in function was 69.1 months. The longest functioning implants had been in function for 180 months. DISCUSSION: The results, from 2 private offices in conjunction with numerous restorative clinicians, utilizing a variety of augmentation materials and implants, were comparable to those reported by other authors. The clinical predictability of sinus augmentation therapy and of implants functioning in augmented sinuses were reinforced. CONCLUSION: Predictable sinus augmentation therapy may be obtained through the use of a variety of regenerative materials. Titanium implants of various configurations and surface topographies will function successfully in augmented sinuses over time.

Implant treatment in an urban general dentistry residency program: a 7-year retrospective study.

Survival rates of multiple implant designs placed in various clinical situations average more than 90%. However, little data have been published on the survival rates of implants placed in dental residency programs. This study reports on the outcome of dental implants placed by first-year general dentistry residents in the University of Florida College of Dentistry-Jacksonville Clinic. The patients for this study received both surgical and restorative implant therapy from 1998 to 2005. A total of 263 patients (147 women, 116 men) were treated with dental implants. On average, a patient was 55.5 years old and received 3 implants. A variety of simple and complex restorative procedures were performed. Advanced general dentistry residents in conjunction with supervisory faculty treated all cases. The cumulative implant survival was 96.6%. Follow-up varied from 6 months to 7 years after placement. Cases included implants not yet loaded as well as implants loaded for 6 years or more. The findings of this study compare favorably with published studies and were unexpected in light of the residents' limited clinical experience.

Retrospective cohort study of the clinical performance of 1-stage dental implants.

PURPOSE: To evaluate long-term clinical performance of 1-stage dental implant prostheses at a single clinic, emphasizing clinical and demographic characteristics that affect implant survival. MATERIALS AND METHODS: Dental records of all 308 patients (674 implants) treated with 1-stage implants at Mayo Clinic from October 1993 through May 2000 were reviewed from implant placement to last visit. Exposure and outcome variables affecting performance were collected separately to control bias in the data collection process. Additional confounding factors (age and sex) were adjusted with the stratified Cox proportional hazards model. Implant survival was determined by means of a Kaplan-Meier survival estimate. The log-rank test was used to determine the role of clinical and demographic variables in implant survival. The relative risk associated with the possible effect of clinical and demographic variables on implant survival was estimated with the Cox proportional hazards model. RESULTS: The implant survival rate (n = 654 implants) was 97% (mean +/- SD follow-up, 21.0 +/- 18.8 months; range, 1 to 78 months). Performance bias was limited because nearly all patients were treated by 1 prosthodontist. Two implants failed after loading (6 and 9 months). The incidence of complications was less than 4%. Among the implant failures, use of heterogeneous bone graft was associated with 4.8 times more failures than was use of autogenous bone graft (P = .04). After augmentation, delaying implant placement for 5 to 6 months resulted in 8.6 times more failures than the rate after earlier placement (P < .001). DISCUSSION: Retrospective review of the clinical performance of a 1-stage dental implant system yielded a 97% survival rate, with no failures noted after 13 months. Prosthetic complications were low, especially for fixed implant prostheses. CONCLUSION: Clinical performance of 1-stage dental implant prostheses between 1993 and 2000 demonstrated a high level of predictability.

A survey of clinical members of the association of dental implantology in the United Kingdom. Part II. The use of augmentation materials in dental implant surgery.

The following were the objectives of Part II of the survey: (1) to determine which augmentation materials were used by respondents, (2) to elicit which factors influenced the choice of augmentation materials, (3) to establish the perceived levels of evidence that support augmentation materials, and (4) to ascertain the clinical applications of particulate augmentation materials (autografts, allografts, and alloplasts). Autogenous bone and demineralized freeze-dried bone are used most frequently. The majority of respondents involved in bone augmentation indicated that alloplasts and allografts should be used to correct small defects or as volume expanders in conjunction with autogenous bone. Research publications and personal clinical observation mainly determine the choice of an augmentation material. Of the clinicians who preferred to use autogenous bone, 26.3% thought that there was at least one randomized controlled trial with histological evidence supporting its use in oral implantology. In comparison, 30% of demineralized freeze-dried bone users thought that there was at least one randomized controlled trial with histological evidence supporting its use. Collected bone debris is currently used for the correction of bone dehiscences and fenestrations around endosseous dental implants in the simultaneous implant-placement augmentation technique. There is a pressing requirement for the two most commonly used augmentation materials (autogenous bone and demineralized freeze-dried bone) to be evaluated by accepted scientific protocols. Although regard for autogenous bone as an augmentation material is high, its use in the form of collected bone debris seems to be limited at present.

Changes in the provision of implant-supported prostheses at the Academic Centre for Dentistry Amsterdam (ACTA) from 1989 to 1995.

PURPOSE: Over the last decade, oral implantology has become a major treatment modality to aid the restoration of reduced dentitions. The present study monitored and quantified changes within a 5-year interval (1989-1991 [denoted as 1990*] to 1995) in the provision of different types of implant-supported superstructures and characteristics of recipient patients at the Academic Centre for Dentistry Amsterdam (ACTA). MATERIALS AND METHODS: All patients who received oral implants in 1990* and in 1995 were selected, and their files (95 and 105, respectively) were consulted. Data of interest were retrieved retrospectively, compared, and statistically analyzed using Chi-squared tests. RESULTS: A number of statistically significant differences was apparent between these 2 periods. By 1995 there was a threefold increase in both the number of patients and the number of implants placed per year. The patient group of < or = 40 years of age had significantly increased, from 7% to 23%. Also, in 1995 more maxillae were implanted than in 1990* (44% vs 26%). Whereas the majority of implanted patients was edentulous in 1990* (64%), the majority in 1995 was partially edentulous (60%). By 1995, the new technique of guided bone regeneration (GBR) using membranes was evidenced (no GBR in 1990* vs 33% of all patients in 1995 receiving some form of local GBR therapy). With respect to the type of superstructures, there was a strong increase in the number of single-tooth replacements (from 4% to 23%). In the edentulous group, the majority of superstructures in 1990 was fixed prostheses (64%), whereas in 1995 the majority was overdentures (71%). CONCLUSION: Major changes in oral implantology treatments were noticed between the 1990* and 1995 periods at ACTA. There is a trend toward implanting younger patients for partial implant-supported reconstructions using more regenerative procedures and with a more equal distribution in the maxilla and mandible.