A comparison of hydroxyapatite (HA) -coated threaded,HA-coated cylindric,and titanium threaded endosseous dental implants

PURPOSE: The purpose of this study was to compare the success of hydroxyapatite (HA) -coated and machined titanium (Ti) implants in a 5-year randomized, controlled clinical trial conducted at 2 centers. MATERIALS AND METHODS: Each of 120 edentulous patients received HA-coated threaded, HA-coated cylindric, and machined Ti threaded implants in a randomized design using 5 or 6 implants. Digital radiographs allowed for yearly measurements of bone loss. Calibrated clinicians also measured mobility, Gingival Index, Plaque Index, probing depth, and recession. A Kaplan-Meier analysis was used to compare the proportion of ailing implants (defined as less than 2 mm of alveolar bone loss over 5 years) for each type of implant design. The criteria employed to assess implant outcome included the need for successful implants to lose less than 2 mm of bone support over the 5 years following placement of the prosthesis. RESULTS: This analysis revealed that 95.2% of machined Ti threaded implants and 97.92% of HA-coated threaded implants were successful, while 99.0% of HA-coated cylindric implants experienced less than 2 mm of bone loss (P < .06). DISCUSSION: All types of implants placed in this study had success rates above 95%. CONCLUSION: Over 5 years, the success rate tended to favor HA-coated implants.     

Marginal bone loss pattern around hydroxyapatite-coated versus commercially pure titanium implants after up to 12 years of follow-up

PURPOSE: The purpose of this study was to compare the marginal bone loss (MBL), complications, and 12-year survival rates of commercially pure titanium (cpTi) and hydroxyapatite (HA)-coated implants placed in the maxilla. MATERIALS AND METHODS: The study group consisted of 120 patients (77 women, 43 men) treated from 1988 to 1997. A total of 388 implants (156 cpTi and 232 HA-coated) were placed in the maxilla. There were 126 immediate (32.5%) and 262 (67.5%) nonimmediate implants. Patients were evaluated annually. Mean follow-up was 60 +/- 32.3 months. MBL was measured on radiographs using the implant threads as the dimensional reference. MBL, complications, and 12-year survival and success rates were correlated with implant coating, time of implantation, implant dimensions, and position in arch. RESULTS: Total mean MBL was 1.07 +/- 2.16 mm. MBL was significantly lower with cpTi implants (0.55 +/- 1.04 mm) compared to HA-coated implants (1.51 +/- 2.71 mm) (P < .001). No statistical difference in regard to MBL was found between immediate and nonimmediate implants (0.86 +/- 1.8 mm vs 1.16 +/- 2.3 mm). The total 12-year survival rate was 91.4%. HA-coated implants had a significantly higher 12-year survival rate than cpTi implants (93.2% vs 89%; P < .03). Nonimmediate implants had a significantly higher failure rate (8.2%) than the immediate implants (1.3%) (P < .009). No correlation was found between type of implant coating and late implant failure. DISCUSSION: Immediate implants can serve as a predictable option, providing higher survival and success rates. HA-coated implants tended to fail less during the surgical phase, but had higher mean MBL compared to cpTi implants. CONCLUSIONS: HA-coated implants had greater MBL than cpTi implants but a higher 12-year survival rate. Immediate implants had a lower failure rate than the nonimmediate implants in this study population.     

Retrospective evaluation of complete-arch fixed partial dentures connecting teeth and implant abutments in patients with normal and reduced periodontal support

STATEMENT OF PROBLEM: The clinical outcome of complete-arch fixed prostheses supported by implants and natural tooth abutments in patients with normal or reduced periodontal support has been reported by few studies, with controversial results. PURPOSE: The purpose of this study was to report on the implant success rate, prosthetic complications, and the occurrence of tooth intrusion, when complete-arch fixed prostheses, supported by a combination of implants and teeth, were fabricated for patients with normal and reduced periodontal support. MATERIAL AND METHODS: Nineteen patients with residual teeth that served as abutments were consecutively treated with combined tooth- and implant-supported complete-arch fixed prostheses and were retrospectively evaluated after a period varying from 24 to 94 months. Nine patients showed reduced periodontal support as a result of periodontal disease and treatment (RPS group), and 10 patients had normal periodontal support of the abutment teeth (more than 2/3 of periodontal support [NPS group]). Ninety implants and 72 tooth abutments were used to support 19 fixed partial dentures. Screw- and cement-retained metal-ceramic and metal-resin prostheses were fabricated with rigid and nonrigid connectors. Implant survival and success rates, occurrence of caries and tooth intrusion, and prosthetic complications were recorded. The number of teeth, implants, prosthetic units, fixed partial dentures, and nonrigid connectors were compared with a t test to assess differences between the 2 groups, while data for the occurrence of intrusions and prosthetic complications were compared with the Fisher exact test (alpha=.05). RESULTS: One of the 90 implants was lost (99% survival rate) over 24 to 94 months, while 3 implants showed more than 2 mm of crestal bone loss (96% success rate) over the same period. No caries were detected, but 5.6% (4/72) of the abutment teeth exhibited intrusion. Intrusion of abutment teeth was noted in 3 patients who had normal periodontal support (13% of teeth in NPS group) of the abutment teeth and was associated with nonrigid connectors. No intrusion of teeth was noted in the patients exhibiting reduced periodontal support regardless of the type of connector or when a rigid connector was used for either group. The number of intruded teeth was significantly greater in patients with intact periodontal support (P=.03). CONCLUSIONS: Complete-arch fixed prosthesis supported by implant and tooth abutments may be associated with intrusion of teeth with intact periodontal support when nonrigid connectors are used to join the implant- and tooth-supported sections of the prostheses. However, fixed partial dentures supported by implants and teeth with reduced periodontal support were not associated with tooth intrusion, regardless of the type of connectors used.     

Implant surface coating and bone quality-related survival outcomes through 36 months post-placement of root-form endosseous dental implants

Survival rates from placement to 36 months were reported for the ongoing Dental Implant Clinical Research Group studies of root-form endosseous dental implants. Failure rates for all implants were similar in bone qualities 1 and 2 (6.2% and 6.7%, respectively) and slightly higher in bone qualities 3 and 4 (8.5% and 8.7%, respectively). Hydroxyapatite (HA)-coated implants had an overall failure rate of 3.9% over 36 months in all bone qualities combined, while non-coated implants had a 13.4% failure rate for the same parameters. For each bone quality, there was a significant difference in implant survival for the non-coated implants (P < 0.01). The highest failure rates for non-coated implants were in bone qualities 3 and 4 (19.1% and 25.5%, respectively). No major difference in survival was found for HA-coated implants placed in each bone quality. Possible reasons for the differences in survival are discussed.     

Peri-implant tissue response of immediately loaded, threaded, HA-coated implants: 1-year results

STATEMENT OF PROBLEM: Although high success rates have been reported with immediately loaded implants, the peri-implant tissue response has not been well documented. PURPOSE: This study evaluated implant success and peri-implant tissue response of immediately loaded, threaded, hydroxyapatite (HA)-coated root-form implants supporting mandibular bar overdentures with opposing conventional maxillary complete dentures in humans. MATERIAL AND METHODS: Five patients (3 men, 2 women; mean age 61 years) each received 4 HA-coated endosseous root-form implants in the interforaminal region in the mandible. The implants were rigidly splinted with a metal framework within 24 hours. The final EDS clip prosthesis was placed 1 to 2 weeks thereafter. The implants and peri-implant tissues were evaluated clinically and radiographically 0, 1, 3, 6, and 12 months after prosthesis placement. Data were analyzed with a repeated measures 1-way analysis of variance (P<.05). RESULTS: All implants were stable at the end of the observation period (mean Periotest value = -5.9 +/- 1.4). No peri-implant radiolucencies were noted, and no implants were lost. The mean marginal bone changes were -0.42 plus minus 0.34, -0.84 +/- 0.55, -1.14 +/- 0.80, and -1.16 +/- 0.89 mm at the 1-, 3-, 6-, and 12-month follow-ups, respectively (P<.001). Significant declines in the rates of marginal bone changes at each time interval were noted (P<.001). In addition, there were significant decreases in probing depth (P<.001) and plaque index (P<.001) but no significant difference in the frequency of bleeding upon probing (P=.64). CONCLUSION: Within the limitations of this study, the peri-implant tissue response of immediately loaded, HA-coated implants was favorable and comparable to that of conventional, delayed-loaded implants after 1 year.     

A 2‐year report on maxillary and mandibular fixed partial dentures supported by Astra Tech dental implants. A comparison of 2 implants with different surface textures.

In 50 partially edentulous patients, 133 (48 maxillary; 85 mandibular) Astra Tech dental implants of 2 different surface textures (machined; TiO‐blasted) were alternately installed, supporting 52 fixed partial dentures (FPDs). Before abutment connection 2 machined implants (1 mandibular; 1 maxillary) were found to be non-osseointegrated and were replaced. Another implant could not be restored due to a technical complication. Two FPDs were remade because of technical complications, both because of abutment fractures. Thus, after 2 years in function, the cumulative survival rates were 97.7% and 95.7% for implants and prostheses, respectively. There was no statistically significant difference in survival rate between the 2 types of implants, 100%(TiO‐blasted) vs 95.3%(machined), P =0.24. After 2 years in function, when both jaw and type of implants were combined, the mean (SD) marginal bone loss was 0.24 (0.69) mm. No statistically significant difference in bone loss was found between the 2 tvues of implant after 2 years of loading, 0.04 (0.82) mm, P >0.30.     

A 3 to 4 year study of single tooth hydroxylapatite coated endosseous dental implants.

OBJECTIVE: To evaluate the clinical effectiveness, common complications and maintenance associated with hydroxylapatite (HA) coated cylindrical implants when used to support single crowns. DESIGN: A prospective medium term clinical study of the Calcitek HA-coated implant. SETTING: Implant placement, crown fabrication and follow-up procedures were carried out at the Leeds Dental Institute, between 1990 and 1998. SUBJECTS AND METHOD: 26 patients (33 implants) participated in the trial. They were referred from general dental practitioners because of their suitability for single tooth implant placement. MAIN OUTCOME MEASURES: The implants were assessed using recognised clinical review procedures e.g. radiographs and soft tissue assessments. RESULTS: At exposure there was 100% implant integration. The cumulative survival rate over 4 years was 100%. In five implants there was cervical bone loss of more than 4 mm and these were classified as failing. This gave an overall cumulative success rate of 58% by year 4. CONCLUSION: The Calcitek HA-coated single tooth implant shows exceptionally high initial integration however, the longer term results suggest that the cervical bone level adjacent to the implant failed to establish a steady state. Doubts remain regarding the long-term prognosis of these cylindrical HA-coated implants.     

Long-term evaluation of implant survival in augmented sinuses: a case series

This study compared bone grafting regimens and different implant surfaces used for sinus augmentation and presented long-term implant success rates in augmented sinuses. Two hundred fifty-seven consecutive patients with 625 implants were evaluated retrospectively. In phase 1, 188 sinuses were grafted with (1) autograft alone; (2) autograft + demineralized freeze-dried bone allograft (DFDBA) + absorbable hydroxyapatite (AHA) in a ratio of approximately 1:3:3; or (3) DFDBA + AHA + nonabsorbable HA (NHA) in a ratio of approximately 1:1:1. In phase 2, grafting regimen 3 (combination of DFDBA + AHA + NHA) was used in another 69 patients. Data were analyzed based on bone grafting regimen, implant surface texture, and time of implant placement (immediate or delayed). In phase 1, graft type 3 had the lowest implant failure rate (2.7%), followed by type 2 (14.3%) and type 1 (44.4%). The overall implant failure rate was 3.6%. Smooth implants showed the highest failure rate (21.8%), followed by titanium plasma-sprayed (2.9%) and HA-coated (0.7%) implants. In phase 2, the overall implant survival rate was 92.5% after 3 years. Smooth implants showed the highest failure rate (41.7%), followed by sand-blasted, large-grit, acid-etched (6.8%) and HA-coated (3.4%) implants. All failures occurred when implants were placed simultaneously with sinus grafts. This study suggests that long-term implant success can be obtained when maxillary sinuses are augmented with a combination of DFDBA + AHA + NHA. Rough surfaces and delayed implant placement seem to increase implant success in these areas.     

Clinical follow-up of unilateral, fixed dental prosthesis on maxillary implants

Aims/Background: The aims of the present study were to evaluate (1) the success rate of unilateral maxillary fixed dental prosthesis (FDPs) on implants in patients at a periodontal clinic referred for periodontal treatment, (2) the prevalence of varying mechanical and biological complications and (3) effects of potential risk factors on the success rate. Material and methods: Fifty consecutive patients were invited to participate in a follow‐up. The patients had received FDPs on implants between November 2000 and December 2003 after treatment to achieve optimal peridontal health, and the FDPs had been in function for at least 3 years. A questionnaire was sent to the patients before the follow‐up examination. Forty‐six patients with 116 implants were examined. The follow‐up comprised clinical and radiographic examinations and evaluations of treatment outcome. Results: Before implant treatment, 13% of the teeth were extracted; of these, 80% were extracted due to periodontal disease. No implants had been lost before implant loading. One implant in one patient fractured after 3 years of functional loading and three implants in another patient after 6.5 years. The most frequent mechanical complications were veneer fractures and loose bridge screws. Patients with peri‐implant mucositis had significantly more bleeding on probing around teeth and implants. Patients with peri‐implantitis at the follow‐up had more deep periodontal pockets around their remaining teeth compared with individuals without peri‐implantitis, but these differences were not significant. Smokers had significantly fewer teeth, more periodontal pockets ≥4 mm and a tendency towards greater marginal bone loss at the follow‐up, compared with non‐smokers. Conclusion: In the short term, overloading and bruxism seem more hazardous for implant treatment, compared with a history of periodontitis. To cite this article:
Wahlström M, Sagulin G‐B, Jansson LE. Clinical follow‐up of unilateral, fixed dental prosthesis on maxillary implants
Clin. Oral Impl. Res. 21 , 2010; 1294–1300.
doi: 10.1111/j.1600‐0501.2010.01948.x     

Implant-supported welded titanium frameworks in the edentulous maxilla: a 5-year prospective multicenter study

PURPOSE: This study evaluated the 5-year clinical and radiographic performance of fixed implant-supported maxillary prostheses with either welded titanium or conventional cast-gold alloy frameworks. MATERIALS AND METHODS: Fifty-eight consecutive patients were provided with 349 osseointegrated Br?nemark system implants in the edentulous maxilla at six different implant centers. Twenty-eight of the patients received, at random, prostheses with laser-welded titanium frameworks, and the remaining 30 patients had prostheses with conventional cast-gold alloy frameworks. Clinical and radiographic data were collected for 5 years after prosthesis placement. RESULTS: The titanium and cast-gold framework groups exhibited similar cumulative survival and success rates (CSR). The 5-year implant CSR from time of placement was 91.4% and 94.0%, respectively, and from prosthesis delivery the rate was 94.9% and 95.6%, respectively. The corresponding 5-year prosthesis CSRs were 96.4% and 93.3%. One patient from each group lost all the implants and turned to complete dentures within the first year of function. Another patient with a cast-gold framework had the prosthesis replaced after 4 years, basically because of problems with the veneering material. No fractures of implant components were observed during the follow-up period. Bone loss was on average 0.59 mm (SD 0.97 mm) during 5 years, with no statistical difference between the two groups. CONCLUSION: Welded titanium frameworks presented a similar favorable clinical performance as conventional cast-gold alloy frameworks in fixed implant-supported prostheses in the edentulous maxilla after 5 years in function. Implant failures were concentrated in only a few patients in each study group.     

Early functional loading at 5 days for Brånemark implants placed into edentulous mandibles: a prospective,open-ended,longitudinal study

BACKGROUND: Traditionally, implants placed in the mandible heal for 3 to 4 months before they are loaded. In maxillae, healing time usually takes 5 to 6 months. The purpose of this study was to evaluate placement of 4 to 6 implants in edentulous mandibles. The implants were placed between mental foramina for support of non-metal, reinforced, fixed, implant-supported provisional prostheses. A unique method was used to convert existing dentures into fixed, implant-supported appliances. The implants were functionally loaded early (5 days). METHODS: Twenty patients with edentulous mandibles or with 2 to 3 remaining mandibular teeth were enrolled in this open-ended, prospective study. Existing dentures without porcelain teeth were modified for use as a surgical guide. These dentures were used as temporary fixed prostheses. Patients were to have metal-reinforced appliances fabricated by the referring dentists after 3 to 4 months of healing. After implant installation, prosthetic abutments were fixed to the implants and tightened to 20 Ncm without counter torque. Bone quality and quantity as well as implant size and position were entered into a computer database. Impression copings were attached to the abutments, and the modified denture was used for a pick-up impression. After the impression was made, implant replicas were fitted to the impression copings and casts were poured. Gold cylinders were processed into the tissue side of the denture. Laboratory screws were used to attach the denture with gold cylinders to abutment replicas. The dentures were processed, polished, and inserted 5 days after implant surgery. Radiographs were taken to verify proper fit of the gold cylinders to the prosthetic abutments (baseline). Radiographs were taken at each follow-up visit and were used to measure changes in crestal bone levels. RESULTS: Twenty patients received 92 machined-surface commercially pure titanium implants in fully edentulous mandibles. Of the total number of implants placed, two were lost between 0 to 1 year and one between 1 to 2 years. Twenty patients with a total of 90 implants were followed between 0 to 1 year. Fourteen patients have been followed between 1 to 2 years, 7 between 2 to 3 years, and 2 between 3 to 4 years. One patient died after 9 months of loading (4 implants loaded, 2 sleeper implants); another died between 1 to 2 years. A total of 6 implants remained buried (sleepers). At 2 years, the cumulative success rate is 96.3%. Survival of the implant bridges is 100.00%. The mean crestal bone level at 5 days for 11 patients was 2.1 mm (SD 0.526, SE mean 0.159) (measurements were not available for the deceased patient), while the mean level at an average of 15 months was 1.96 mm (SD 0.585, SE mean 0.176). Differences between the measurements taken at 5 days with those taken at an average of 15 months were not significant (P < 0.683). CONCLUSIONS: Results of this study indicate that 4 to 5 implants can be placed and loaded within 5 days of implant insertion with high success (96.3%). Success rates for the interim and final prosthesis are 100%. A simple, possibly cost-effective method of using non-metal reinforced dentures as interim fixed, provisional dentures has been described. Impressions and registrations for making the prosthesis can be made at the time of implant installation, and this method is accurate enough to make provisional restorations. The modified denture can function as an interim fixed, implant-supported prosthesis for up to 30 months. Results of x-ray measurements indicate stable crestal bone levels for up to an average of 15 months.     

Survival of hydroxyapatite-coated implants: A meta-analytic review

PURPOSE: Some reports show a benefit of coating dental implants with hydroxyapatite (HA), and others assert that resorption of the HA coating compromises long-term implant survival. This study examined this controversy by systematically reviewing all the current literature that reports the outcomes of HA-coated implants in human clinical trials. MATERIALS AND METHODS: A systematic Medline computer search of the English literature yielded 45 human clinical trials that reported on the outcome of HA-coated implants. Eleven studies that met specific inclusion criteria were selected for detailed analysis. The studies were divided into 2 groups. One group of 5 studies reported implant survival using overall percentage, and another group of 6 studies reported implant survival using life-table analysis. RESULTS: The overall percentage survival rates ranged from 93.2% to 98.5%, with 4 to 8 years of follow-up. The cumulative survival rates for studies that used life-table analysis ranged from 79.2% to 98.5%, with 5 to 8 years of follow-up. The yearly interval survival rates reported for the studies using life-tables were variable but remained above 90% and did not show a progressive or precipitous decrease with increasing years of follow-up. CONCLUSIONS: The survival rates reported for HA-coated implants were similar to the survival rates reported for uncoated titanium implants. If resorption of the HA coating causes late failure of implants, the yearly interval survival rates should have decreased with increased years of follow-up. This decrease was not observed in the longitudinal human clinical trials that met the selection criteria for this study. Detailed analysis of these clinical trials did not show that HA-coating compromises the long-term survival of dental implants.     

Fixed implant‐supported prostheses in the edentulous maxilla. A five‐year follow‐up report.

Seventy‐six patients were consecutively treated with fixed prostheses supported by osseointegrated implants in the edentulous maxilla and followed up for 5 years. The mean bone quality and resorption indices were 3.1 and 2.7 at the time of implant placement, respectively. Altogether, 449 standard Brånemark implants were placed. Two patients resumed to complete dentures, and the cumulative implant and prosthesis survival rates were 92.1% and 95.9% for 5 years, respectively. The mean marginal bone level was 0.6 mm below the reference point at the time of placement and 1.2 mm below the same point 5 years later. Speech problems was the most frequent complaint during the first year of function, while resin fractures caused most adjustments during the follow‐up period. No implant, abutment or gold alloy screws were found to be fractured, and only 4 patients had their prostheses re‐tightened due to loose gold alloy screws.     

Comparative study of hydroxyapatite and titanium dental implants in dogs

This study compares the clinical performances and histologic response in dogs to a cylindrical implant with a surface consisting of dense hydroxyapatite (HA) and a threaded titanium implant in functionally loaded and unloaded conditions. Implantation was performed in five dogs, which were killed at 2 or 4 months postfunctional condition (4 or 6 months after implantation). Clinical evaluation showed that neither implant demonstrated significant movement, and assessment of gingival inflammation and sulcus depth showed no significant differences between them. After axial sectioning, the titanium implants were easily removed from the bone, whereas the HA-coated implants were adherent to the bone. Histologically, both implants showed osteogenic ingrowth to the surface in functional and nonfunctional conditions. High-magnification scanning electron micrographs of plastic sections showed that a portion of the interface between the HA-coated implant and the bone showed no gap, whereas gaps were observed at all interfaces with the titanium implant. Histomorphometric analysis by light microscopy indicated that there was no significant difference in the percent bone contact length. Clinically, the two implants behaved similarly.     

Early functional loading of unsplinted roughened surface implants with mandibular overdentures 2 weeks after surgery

Background: Before early functional loading of unsplinted implants with mandibular overdentures can become widespread, more clinical studies are needed to investigate the success of the approach. Purpose: To evaluate the success rates of two types of roughened titanium surface implants with early 2‐week functional loading of paired mandibular interforaminal implants with overdentures. Materials and Methods: Random allocation divided 24 strictly selected edentulous participants into two groups, with each group to receive a different implant system (ITI Dental Implant System, Straumann AG, Waldenburg, Switzerland; or Southern Implant System, Southern Implants, Irene, South Africa). Two implants were placed in the anterior mandible of all participants using one‐stage standardized surgical procedures. Previously constructed conventional mandibular dentures (opposing maxillary complete dentures) were temporarily relined and worn by the participants for the first 2 weeks; participants used a soft diet. Two weeks after implant surgery and following some mucosal healing, the mandibular dentures had the tissue conditioner removed and the appropriate matrices included for an unsplinted prosthodontic design. Results: No implant from either group was lost. Resonance frequency analysis (RFA) indicated higher primary stability at surgery for the Southern group than for the ITI group, with a statistically significant difference between the groups throughout the study period. The drop in RF values between surgery and 6 weeks was significant and was greater for the Southern group. RFA also indicated stabilized osseointegration between 6 to 12 and 12 to 52 weeks, with no participant showing any decrease in those values over time. Participants with type 3 bone showed a significant improvement in RF values between 12 and 52 weeks, eventually matching those of participants with type 2 bone. There were no significant differences in marginal bone loss, periimplant parameters, or prosthodontic maintenance between the groups over the study period. Conclusions: Using only strict patient selection criteria, 1‐year follow‐up data indicate that early functional loading of ITI and Southern implants with mandibular two‐implant overdentures is possible as early as 2 weeks after implant surgery.     

A prospective multicenter clinical investigation of a bone quality-based dental implant system

This article reports the 5-year interim results of an independently monitored, prospective, multicenter clinical trial of a bone quality-based implant design. At six study centers, 495 implants were placed in 151 cases with an average follow-up period of 1.6 years (range: 1.0-3.6 years) after prosthesis delivery. The majority of the implants were placed in D2 or D3 bone to support fixed partial dentures or implant-supported overdentures. Using strict success criteria, there were three implant failures, resulting in a cumulative 99.5% success rate according to Kaplan-Meier survival analysis. Radiographic analysis revealed a mean bone loss of 0.06 mm at 1 year and a bone gain of 0.04 mm at 2 years after prosthesis loading. There were no statistical differences in the results by center, implant type, bone density, area of the mouth, or prosthesis type. The results of this 5-year study revealed a high success rate and limited crestal bone loss in all bone densities by the use of an implant specifically designed for the varying biomechanical conditions and bone quality associated with the human maxilla and mandible.     

慢性中重度牙周炎患者应用种植修复的临床评价

目的：评估对中重度牙周炎患者经完善的牙周治疗及Ⅱ-Ⅲ度松动牙拔除后所导致的牙列缺损及牙列缺失所采用的单冠,联冠,全颌种植义齿修复的远期疗效。方法：共计十例患者经完善的牙周治疗,病情稳定后延期植入80枚种植体,即刻植入16枚植体,5-7个月种植义齿修复,根据种植体与牙槽骨之间的X线影像,牙周袋深度及临床检查等作为评价指标,评价负载后的修复效果。结果：96枚种植体中,其中两枚即刻种植于术后3周脱落,即刻种植成功率87%,种植体的平均存留率为97%,承载3.5年后骨吸收高度平均为（1.73＋0.13）mm。结论：对中重度牙周炎进行牙周治疗,采取慎重态度,运用正确的种植方式,修复方法,则可减少牙槽骨的吸收,并获得理想的修复效果,但同时要坚持定期的口腔护理,但对这类患者的骨吸收还需进一步的远期观察。     

A 5-year prospective multicenter study on 1-stage smooth-surface Brånemark System implants with early loading in edentulous mandibles

PURPOSE: The purpose of the current prospective multicenter study was to evaluate the 5-year implant success and peri-implant conditions of smooth-surface Br?nemark System implants when using a novel technique including a 1-stage surgical procedure with early loading in edentulous mandibles. MATERIALS AND METHODS: The study protocol included 1-stage surgery as well as placement of the definitive prosthesis within 6 weeks after implant insertion (ie, early loading). Clinical evaluation, as well as evaluation of function and esthetics, was performed at each follow-up visit. Radiographs were obtained at connection of the prostheses and at the 1, 3-, and 5-year check-ups. RESULTS: A total of 40 patients with a mean age of 56 years (range, 30 to 70) were included in the study. In all, 170 implants were placed in between the mental foramina, of which 120 implants in 30 patients were associated with overdenture treatment and 50 implants in 10 patients with fixed complete dentures. Twelve implants failed in 6 patients. The cumulative implant survival rate was 92.9% after both 1 and 5 years of follow-up. Another 3 implants were recorded as mobile but still in function when individually checked at the 5-year visit, which resulted in a cumulative success rate of 91.0%. Mean bone remodeling over the study period was less than 0.1 mm/y after the first year of loading, resulting in a mean marginal bone level of 0.66 mm (SD 0.73, n = 138) apical to the implant collar reference point after 5 years. CONCLUSIONS: One-stage, early loaded smooth-surface Br?nemark System implants functioned well for the majority of patients with edentulous mandibles. Stable peri-implant conditions were observed. Bone remodeling resulted in a mean bone level above the first implant thread after 5 years. The somewhat lower success rate of 91.0% compared to a 2-stage procedure may be related to generous inclusion criteria and to a learning curve involving a novel treatment procedure.     

Postmortem histologic evaluation of mandibular titanium and maxillary hydroxyapatite-coated implants from 1 patient.

Postmortem examination of human specimens is an extremely important aspect of evaluating the relative compatibility and long-term success of endosseous implant surfaces. The bone-implant interface of 5 commercially pure titanium screw-type mandibular implants after 85 months of service and 2 hydroxyapatite- (HA) coated maxillary implants after 38 months of service were examined. All implants were stable at the time of the patient's death. The mandibular implants had an average of 65% contact with bone and the maxillary implants had an average of 47% contact. The HA coating had separated from the maxillary implants in some areas and was free within surrounding connective tissue or surrounded by invaginating sulcular epithelium. The arrangement and pattern of bone contact appeared different between HA-coated and titanium implant surfaces.