Oral implants in radiated patients: a systematic review

PURPOSE: Oral malignancy is often treated with a combination of surgery and radiation therapy (RT). The aim of this systematic review was to examine the effects of pre- and postimplantation RT on dental implant failure. MATERIALS AND METHODS: The literature published from 1990 through 2006 was reviewed for studies assessing pre- and postimplantation RT. Potential studies were identified by searches of PubMed, SCIRUS, and the Cochrane Central Register of Controlled Trials (CENTRAL). The incidence of implant failure has been linked to the following variables: post- versus preimplantation RT, site of implant placement, RT dose, delay from RT to implant placement, and timing of implant failure after placement. RESULTS: Similar failure rates were found for implants placed post-RT compared to those placed pre-RT (3.2% and 5.4%). In preimplantation RT, the implant failure rate was lower for the mandible (4.4%) in comparison to the maxilla (17.5%; OR = 4.63; 95% CI: 2.25 to 9.49). Other results did not reach statistical significance. No failures were observed in association with an RT dose lower than 45 Gy. All implant failures observed occurred within 36 months after RT, and most occurred between 1 and 12 months after placement. CONCLUSION: Notwithstanding the low number of implants evaluated, this review showed similar failure rate for implants placed post-RT and those placed pre-RT (3.2% and 5.4%, respectively).     

Factors Affecting Survival and Usefulness of Implants Placed in Vascularized Free Composite Grafts Used in Post–Head and Neck Cancer Reconstruction

Background: Bone‐containing vascularized grafts have been used successfully to reconstruct post‐cancer surgical defects. Dental implants can be placed in these bone‐containing grafts to allow implant‐supported prosthodontic reconstruction of these patients. Purpose: The aim of this study was to evaluate the survival of dental implants used in the rehabilitation of subjects treated with bone‐containing vascularized grafts to compare usability of implants placed at the time of reconstruction and after healing. Materials and Methods: A cross‐sectional study was undertaken to examine survival rates of implants placed in vascularized bone‐containing grafts either immediately at the time of surgical reconstruction or after 3 months healing. Other factors such as graft type, whether radiation therapy was given, and implant type were recorded. Results: A total of 41 patients had 145 implants placed in 47 vascularized bone‐containing flaps. Increased failure rate of implants was seen in immediately placed implants. There was also a significant increase in the number of osseointegrated implants that were prosthodontically unusable or sub‐optimally placed in the immediate placement group. Radiation therapy was associated with a significant increase in failure rate. Modern implant surfaces appeared to perform better than machined/turned surfaces. Graft donor site did not influence implant survival. Conclusion: This study demonstrated the difficulties encountered with immediate placement of dental implants at the time of post‐cancer reconstructive surgery.     

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.     

Oral rehabilitation with dental implants after cancer treatment

Background: Patients who undergo surgical management of oral cancer may greatly benefit from an implant‐supported prosthesis. This study reports on the clinical experience of dental implant placement in patients following resection of oral cancer over a 15‐year period. Controversies including the use of dental implants in irradiated tissues, and hyperbaric oxygen treatment will also be discussed. Methods: Thirty‐one patients who had dental implants placed as part of their oral rehabilitation between 1992 and 2007 were investigated. Demographic data and factors including implant survival, type of prosthesis provided, radiotherapy and the hyperbaric oxygen therapy were analysed. Results: In this retrospective study, there was a retention rate of 110 implants from a total of 115 implants placed. A high rate of implant retention was found, with 5 implant failures from a total of 115 implants placed. The 5 failed implants occurred in free flap bone that had been irradiated. Conclusions: Dental implants provide an important role in the oral rehabilitation of oral cancer patients. There may be an increased risk of implant failure in free flap bone that has been irradiated.     

Dental endosseous implant assessments in a type 2 diabetic population: a prospective study

Diabetes mellitus, a prevalent disorder worldwide, is associated with systemic adverse sequelae, such as wound healing alterations, which may affect osseointegration of dental implants. This prospective multicenter study assessed the success of 2-stage endosseous root-form implants (3 different implant systems) placed in the mandibular symphysis of 89 male type 2 diabetic subjects. The implants were uncovered approximately 4 months after placement, restored with an implant-supported, Hader bar clip-retained overdenture, and maintained at scheduled follow-up data collection examinations for 60 months after loading. Sixteen (9.0%) of the 178 implants failed. Life table methods calculated implant survival at approximately 88%, from prosthesis placement through the 60-month follow-up, and at approximately 90% from implant placement through the observation period. No implants failed between surgical placement and uncovering, 5 failed at uncovering, 7 failed after uncovering before prosthesis placement, and 4 failed after prosthesis placement. Fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1c) values were determined before implant placement (baseline) and approximately 4 months later at surgical uncovering (follow-up). The 5-year implant outcomes (successes versus failures) were analyzed against the following predictor variables: (1) baseline and follow-up FPG values, (2) baseline and follow-up HbA1c values, (3) subject age, (4) duration of diabetes (years), (5) baseline diabetic therapy, (6) smoking history, and (7) implant length. Regression analysis found only duration of diabetes (P < .025) and implant length (P < .001) to be statistically significant predictors of implant failure. There was no statistically significant difference in failure rates between the 3 different implant systems used. This study supports the use of dental implants in type 2 diabetic patients.     

Effects of Untreated Periodontitis on Osseointegration of Dental Implants in a Beagle Dog Model

Background: There have been previous studies on the relationship between periodontitis and peri‐implantitis, but limited information is available on how periodontitis affects osseointegration and wound healing of newly placed dental implants adjacent to natural teeth. The objective of the present experiment is to evaluate healing around dental implants adjacent to teeth with untreated experimental periodontitis. Methods: The study included six male beagle dogs. Scaling and plaque control procedures were performed on three dogs (control group). In the other three dogs (experimental group), retraction cords and ligature wires were placed subgingivally around all premolars and the first molars. Induced experimental periodontitis was confirmed after 3 months. Each control or experimental group was divided into two subgroups depending on the timing of implant placement (immediate/delayed). Twelve dental implants (two implants for each dog) were placed immediately, and the other 12 dental implants (two implants for each dog) were placed 2 months after extraction. The animals were sacrificed 2 months after implant placement. Histologic and histometric analyses were performed. Results: Four implants (three from the immediate placement group and one from the delayed placement group) failed in the experimental group. There were significant differences in the percentage of bone‐to‐implant contact and marginal bone volume density between the control and experimental groups. Both parameters were significantly lower in the experimental group than in the control group (P <0.05). There was a tendency toward more marginal bone loss in the experimental group than the control group. Conclusions: Immediate placement of implants is associated with a higher failure rate compared with delayed placement. Untreated experimental periodontitis was correlated with compromised osseointegration in the implants with delayed placement.     

Retrospective multicenter analysis of 3i endosseous dental implants placed over a five‐year period

Osseointegrated dental implants have now become an accepted form of treatment for patients with a fully or partially missing dentition. The purpose of this study was to evaluate the performance of 3i threaded and cylindrical implants. During a 5-year period, a total of 1969 3i endosseous implants were placed at 6 centers in the United States and 2 elsewhere in the edentulous and partially edentulous jaws of 653 consecutive patients ranging in age from 18 to 82 years. Of the total number of implants placed, 1341 were commercially pure titanium threaded implants and 628 were titanium plasma-sprayed implants with a cylindrical configuration. A total of 28 patients with 110 implants were lost to follow-up. Implants in these patients were considered neither a success nor a failure. Success was predicated on the osseointegration of each and every implant followed in this analysis rather than the persistence of prosthetic function. Confirmed bone anchorage was considered essential for success. A total of 625 patients with 1871 implants remain in the study with a follow-up period ranging from 6 to 60 months. A total of 93 implants (5.0% of the total implants followed) were considered as failures. A mean implant survival rate was 95.0% for both the threaded and the cylindrical implant was calculated. The success rate of threaded implants was 97.0% in the mandible and 93.8% in the maxilla. The success rate for the 3.3mm cylindrical implants was 96.0% in the mandible and 95.5% in the maxilla, and the success rate of 4.0mm diameter cylindrical implants was 95% in the mandible and 92.0% in the maxilla. Causes of failure consisted of loss of osseointegration 2.3%crestal bone loss requiring periodontal therapy after the first year of function 1.7% and mechanical problems associated with the prosthesis 0.9%. This retrospective analysis of the 3i endosseous implant system is comparable to previous reports on other implant systems in terms of implant survival and prosthesis stability. It is demonstrated that 3i implants are predictable and can provide lasting osseointegration leading to improvement of oral function if the recommended surgical and restorative protocol is followed.     

Fresh‐Frozen Bone Allografts in Maxillary Alveolar Augmentation: Analysis of Complications,Adverse Outcomes,and Implant Survival

Background: Success of any bone augmentation procedure is dependent on several factors. Because complications occur in some cases, the aims of this study are to analyze adverse events associated with placement of fresh‐frozen bone allografts (FFBAs) during alveolar ridge augmentation and to assess 1‐year survival of dental implants placed in reconstructed sites. Methods: Fifty‐eight consecutive patients (15 males and 43 females, aged 38 to 76 years; mean age: 58 ± 9.2 years) requiring maxillary bone reconstruction prior to implant placement were enrolled in this study. A total of 268 implants was subsequently placed in sites reconstructed with FFBAs. There were 22 posterior grafted sites, 19 anterior, and 17 full‐arch sites. After a 4‐ to 6‐month integration period, all patients received an implant‐supported fixed prostheses. Complications occurring during treatment and the 12‐month follow‐up period were recorded and evaluated. Results: Thirteen of 58 (22.41%) patients experienced some kind of complication in the receptor site. Infection occurred in six (10.34%) individuals, dehiscence in five (8.62%), and mucosal perforation in seven (12.07%). Adverse outcomes categorized as partial and total graft loss occurred in four (6.90%) and three (5.17%) patients, respectively. Implant failure rate was 16 (5.97%) of the 268 fixtures placed in 12 (20.70%) of 58 patients. Conclusions: Infection and suture dehiscence are significantly correlated with graft loss in a maxillary FFBA augmentation. Patients with full‐arch grafting reconstructions lost significantly more implants. Early diagnosis and prompt management of adverse events seem to be of great importance in prevention of total graft loss.     

Effects of smoking on the outcome of implant treatment: a literature review.

STATEMENT OF PROBLEM: The use of osseointegrated implants as a foundation for the prosthetic replacement of missing teeth has become widespread in the last decade. Owing to the remarkable success of dental implants, there has been growing interest in identifying the factors associated with implant failure. Given the well-documented deleterious effect of smoking on wound healing after tooth extraction and its association with poor quality bone and periodontal disease, a negative effect of tobacco use on implant success is to be expected. PURPOSE: To establish the relationship between smoking and implant-related surgical procedures (i.e, sinus lift procedures, bone grafts and dental implants), including the incidence of complications related to these procedures and the long-term survival and success rates of dental implants among smokers and nonsmokers based on relevant literature.MATERIALS AND METHODS: Relevant clinical studies published in English between 1990 and 2006 were reviewed. The articles were located through Medline and, manually, through the references of peer-reviewed literature. This was supplemented with a hand search of selected dental journals and text books.RESULTS: The majority of the past and current literature implicates smoking as one of the prominent risk factors affecting the success rate of dental implants with only a handful of studies failing to establish a connection. Most of the studies report the failure rate of implants in smokers as being more than twice that in nonsmokers. These findings are difficult to ignore. There is a statistically significant difference between smokers and nonsmokers in the failure rates of dental implants. Smoking also has a strong influence on the complication rates of implants: it causes significantly more marginal bone loss after implant placement, it increases the incidence of peri-implantitis and affects the success rates of bone grafts. The failure rate of implants placed in grafted maxillary sinuses of smokers is again more than twice that seen in nonsmokers.Conclusion: Smokers have higher failure rates and complications following dental implantation and implant-related surgical procedures. The failure rate of implants placed in grafted maxillary sinuses of smokers is more than twice that seen in nonsmokers.     

One-year follow-up of first consecutive 100 zirconia dental implants in humans: a comparison of 2 different rough surfaces

PURPOSE: The aim of this study was to evaluate the success rate of 100 consecutive zirconia dental implants with 2 different rough surfaces after 1 year of follow-up. MATERIALS AND METHODS: One-piece zirconia dental implants (CeraRoot, Barcelona, Spain) with 1 of 2 different roughened surfaces were designed and manufactured for this study. Five different implant designs were manufactured. Standard or flapless surgical procedures were used for implant placement. Simultaneous bone augmentation or sinus elevation were performed in the cases where bone height or width was insufficient. Implants in the anterior region (canine to canine) were immediately restored with provisional prostheses. Implants placed using less than 35 N torque were splinted with composite resin using an etched and bonded approach to the neighboring teeth or implants to minimize implant mobility and failure. Definitive all-ceramic restorations were placed 4 months after implant placement (8 months for implants where bone augmentation or sinus elevation was performed). RESULTS: The study included 36 patients with a mean age of 50 years. The overall implant success rate after 1 year of follow-up was 98% in both the coated and noncoated groups. CONCLUSIONS: From the preliminary results of this investigation, it can be concluded that zirconia dental implants with roughened surfaces might be a viable alternative for tooth replacement. Further follow-up is needed to evaluate the long-term success rates of the implant surfaces studied.     

Sinus augmentation bone grafts for the provision of dental implants: report of clinical outcome

PURPOSE: The aim of this study was to report the outcome of sinus augmentation surgery with autogenous bone grafting in routine dental implant practice. MATERIALS AND METHODS: Twenty-seven sinus augmentation procedures were undertaken on 18 consecutive patients (mean age 43.7 years). The mandibular symphysis was used as the donor site for 11 patients. The iliac crest was used as a donor site for 7 bilateral cases. RESULTS: Six patients had implants placed at the time of grafting: the other 13 had a mean bone graft consolidation period of 24.7 weeks (range 9 to 39 weeks) before implants were placed. One patient who had a repeat procedure had both immediate and delayed techniques. A total of 79 Br?nemark System Mk II implants were placed in grafted bone (and 2 Mk IV implants were placed in a patient who had to have a repeat procedure) and proceeded to occlusal loading. After a mean follow-up period of 162 weeks (range 76 to 288 weeks), 16 implants failed to integrate in grafted bone, representing an 80.25% survival rate. Fourteen patients proceeded to the planned prosthesis, 3 patients had a compromised treatment plan, and 1 patient was restored conventionally. This represents 94% of patients who were rehabilitated. DISCUSSION AND CONCLUSION: The sinus augmentation procedure using autogenous bone grafting can Increase bone volume to allow implant placement where there is insufficient bone. The survival of implants in the grafted bone, as measured by integration and successful loading, was reduced compared to implants placed in normal maxillary bone. Infection during the healing of the grafted site reduces the success of subsequent implant osseointegration.     

Retrospective analysis of 56 edentulous dental arches restored with 344 single-stage implants using an immediate loading fixed provisional protocol: statistical predictors of implant failure

PURPOSE: The purpose of this retrospective study was to evaluate the effects of implant dimensions, surface treatment, location in the dental arch, numbers of supporting implant abutments, surgical technique, and generally recognized risk factors on the survival of a series of single-stage Straumann dental implants placed into edentulous arches using an immediate loading protocol. MATERIALS AND METHODS: Each patient received between 4 and 18 implants in one or both dental arches. Periapical radiographs were obtained over a 2- to 10-year follow-up period to evaluate crestal bone loss following insertion of the definitive metal-ceramic fixed prostheses. Univariate tests for failure rates as a function of age (< or = 59 years versus > or = 60 years), gender, smoking, bone grafting, dental arch, surface type, anterior versus posterior, number of implants per arch, and surgical technique were made using Fisher exact tests. The Cochran-Armitage test for trend was used to evaluate the presence of a linear trend in failure rates regarding implant length and implant diameter. Logistic regression modeling was used to determine which, if any, of the aforementioned factors would predict patient and implant failure. A significance criterion of P = .05 was utilized. RESULTS: Data were collected for 344 single-stage implants placed into 56 edentulous arches (39 maxillae and 17 mandibles) of 43 patients and immediately loaded with a 1-piece provisional fixed prosthesis. A total of 16 implants failed to successfully integrate, for a survival rate of 95.3%. Increased rates of failure were associated with reduced implant length, placement in the posterior region of the jaw, increased implant diameter, and surface treatment. Implant length emerged as the sole significant predictor of implant failure. CONCLUSION: In this retrospective analysis of 56 consecutively treated edentulous arches with multiple single-stage dental implants loaded immediately, reduced implant length was the sole significant predictor of failure.     

Survival of immediately loaded dental implants in deficient alveolar bone sites augmented with beta-tricalcium phosphate

PURPOSE: Dental implant placement in atrophic alveolar ridges often necessitates grafting procedures, followed by immediate or delayed implant placement. This study assessed the survival of immediately loaded dental implants placed in deficient alveolar bone sites at bone grafting. MATERIALS: From 1999 to May 2002, 1 operator (A.P.) inserted 1065 implants (607 in mandibles, 458 in maxillae) into 338 partially edentulous patients. Most implants were placed into compromised residual ridges or prepared tooth extraction sockets. Implants placed in augmented areas were splinted to implants in nonaugmented sites for stability. In all cases, beta-tricalcium phosphate was mixed with blood from the surgical site to augment the ridge level or fill spaces between the implant and socket wall. When indicated, the same materials were used for sinus floor augmentation. All implants were tapered screws with roughened surfaces, primarily (75%) from 1 manufacturer. One of the authors (Z.O.) prosthetically restored a total of 189 implants that were placed in 35 patients. In this group of patients, complete restorative data were available. All implants were monitored for 12-48 months (mean = 19.2; median = 24). RESULTS: A total of 1039 implants survived, and 26 failed, including 5 in the anterior mandible and 21 in the maxillae. In the restorative group, 186 implants survived, and 3 maxillary implants failed. All implant failures in this study occurred in the augmented sites. CONCLUSION: Within the limitations of this study, immediate loading of splinted implants in augmented sites is a predictable procedure.     

Survival of NobelDirect implants: an analysis of 550 consecutively placed implants at 18 different clinical centers

Background: A recently introduced implant, the NobelDirect (Nobel Biocare AB, Göteborg, Sweden), has previously been documented with substantial bone resorption in a large number of operated cases. PurposeL The aim of this study was to evaluate the failure rate of NobelDirect implants in a retrospective multicenter survey. Materials and Methods: A total of 550 NobelDirect implants consecutively placed in over 269 patients at 18 centers were evaluated with regard to failure rate after an average follow‐up of about 1 year. Results: The overall failure percentage was 10.9% (59 failures). The 58 implants not loaded directly showed only one failure (1.7%) versus 58 failures (11.8%) of those implants that were loaded directly. A chemical x‐ray photoelectron spectroscopy analysis of an implant from the original batch showed up to 3.5% silicon at parts of the implants. A retrieval analysis of one implant removed at 2 years after placement demonstrated bone resorption down to the level of the fifth thread. Conclusions: It is concluded that the NobelDirect implant, if placed with a punch procedure, ground down in situ, and loaded directly, shows an unusually high failure rate at 1 year.     

A retrospective analysis of implants immediately placed in sites with and without periapical pathology in sixty-four patients

Background: Many patients requiring implant therapy present with hopeless teeth exhibiting periapical pathology. The advisability of implant placement in such situations has not been conclusively determined. Methods: Sixty‐four patients underwent therapy in their maxillary incisor region. Treatment consisted of immediate implant placement in a site demonstrating periapical pathology, and immediate implant placement in a “pristine” site, either during the same visit or during separate visits. The implants placed in the sites demonstrating periapical pathology were followed in function for ≤117 months, with a mean time in function of 64 months. The implants placed in pristine sites were followed in function for ≤120 months, with a mean time in function of 62 months. Results: Two implants in the central incisor positions of one patient demonstrated 2 mm of buccal recession after ≈46 months in function. These implants were deemed esthetic failures, despite the absence of inflammation and continued clinical implant immobility, yielding cumulative survival rates of 98.1 and 98.2 for implants placed in sites with periapical pathology and implants placed in sites without periapical pathology, respectively, according to published criteria. Conclusions: Implants immediately placed in sites demonstrating periapical pathology yielded results comparable to those immediately placed in pristine sites. The difference in survival rates was not statistically significant.     

Five-year outcome of 111 immediate nonfunctional single restorations

Immediate loading is a surgical-prosthetic procedure extensively used in implant dentistry. Despite its frequent use, minimal data are available on the long-term clinical success rate of immediate functional loading (IFL) and immediate nonfunctional loading (INFL) of implants. The aim of this study was to evaluate the long-term survival and bone loss of immediate nonfunctional single implant restorations in a group of patients that were monitored for 5 years. One hundred and eleven patients (41.4% men) with a median age of 40 years were included in this study. A total of 111 implants were placed. All implants were placed with a minimum insertion torque of 25 Ncm. A temporary restoration was relined with acrylic resin, trimmed, polished, and cemented or screw-retained 1 to 2 hours later. Occlusal contact was avoided in centric and lateral excursions. After provisional crown delivery, a periapical radiograph was performed by means of a customized Rinn holder device. Data were analyzed by means of Kaplan-Meier and life-table algorithms. Stratification of implant survival was performed for the available variables of interest, and comparisons were analyzed using a log-rank test. Investigated parameters were time of implant placement, bone quality, implant site, implant diameter and length, and type of implant surface enhancement. The parameters for overall success rate were defined by bone resorption <1.5 mm after the first year of loading and <0.2 mm thereafter. During the 5-year follow-up period, a survival rate of 95.5% was observed. All failures occurred within 4 months of implant loading. There were statistically significant differences regarding healed vs post-extraction implant sites (100% and 92.5%, respectively, P = .05) and type of bone (D1 vs D4 yielded 100% and 95.5%, respectively, P <.05). No differences were detected for: (1) site (100% for mandible and 94.63% for maxilla, P =-.319); (2) implant diameter (survival rates of 97.26% for <4.5-mm diameter and 92.11% for >4.5mm diameter, P = .206); (3) implant lengths (survival rates of 96.97% for implants >13 mm and 94.87% for implants <13 mm, P =.624); and (4) type of implant surface enhancement (survival rates of 94.03% for 67 cases of grit-blasted and acid-etched surfaces and a failure rate of 4 out of 5, and 94.12% for 17 cases of hydroxyapatite (HA)-coated surfaces with only 1 failure). The success rate (defined as bone resorption >1.5 mm after the first year of loading and >0.2 mm thereafter) was 97.2%. Immediate nonocclusal loading of single implants is a reliable surgical-prosthetic procedure with a low rate of implant loss and a low quantity of peri-implant bone loss over time.     

Osteotome sinus elevation and simultaneous placement of porous-surfaced dental implants: a morphometric study in rabbits

The objective was to establish a model in rabbits in which to study the healing events associated with localized indirect osteotome-mediated maxillary sinus floor elevation in conjunction with simultaneous placement of sintered porous-surfaced dental implants. On one side of the maxilla of each of 28 rabbits, a sintered porous-surfaced titanium alloy press-fit implant was placed without the use of a bone graft material, while on the collateral side an implant was placed after first adding Bio-Oss graft particles to the osteotomy. Specimens were retrieved for morphometric assessment of bone contact and bone ingrowth of the porous implant surface after 2, 4, 6 and 8 weeks of healing. All implants became osseointegrated by bone ingrowth into the porous implant surface. While the addition of graft particles did not result in a statistically significant increase in the parameters measured, a trend for greater bone contact and particularly bone ingrowth at the apices of the implants was seen as healing time increased. The rabbit maxillary sinus can be used to study healing following placement of sintered porous-surfaced dental implants using the indirect sinus elevation procedure.     

A comparative evaluation of immediate dental implant with autogenous versus synthetic guided bone regeneration

Immediate implant is a placement of the implant immediately into fresh extraction socket site after tooth extraction and is considered to be a predictable and acceptable procedure. The present work is designed to evaluate the periodontal condition after immediate implant placement and the success rate of implant with autogenous versus synthetic guided bone regeneration. Twenty adult male patients with an endodontic failure, tooth fracture decayed tooth (hopeless tooth) were included in this study. Patients were divided into 2 groups: One group (I) received immediate implants augmented with autogenous bone graft, and the other (group II) received immediate implants augmented with a synthetic bone graft. The results revealed that there was a significant difference between the groups for pocket depth and clinical attachment level. The difference between the groups was statistically highly significant only at 12 months (P < .01). In addition, there was statistically significant difference between the groups at 9 and 12 months (P < .001). Moreover, there was significant decrease of marginal bone loss in group I compared with group II (P < .01). In addition, there was statistically significant difference between the both groups at 9 and 12 months for bone density (P < .001). Moreover, there was significant decrease of marginal bone loss in group I compared with group II (P < .01). In conclusion, the immediate dental implant placement with autogenous bone graft showed a significant superiority to synthetic bone graft. In addition, the immediate placement-delayed loaded dental implant remains the procedure of choice for predictable achieving of osseointegration.     

Prospective clinical trial of dental implants in persons with ectodermal dysplasia

STATEMENT OF PROBLEMS: Ectodermal dysplasia is a hereditary condition in which hypodontia is the second most frequently occurring sign. Hypodontia is associated with lack of development of the alveolar ridge and results in less volume of bone for support of conventional prostheses. Minimal development of the alveolar ridge can affect the bone volume available for the placement of dental implants. Purpose. This clinical trial evaluated the survival of implants placed in individuals with a form of ectodermal dysplasia and severe hypodontia. MATERIAL AND METHODS: Two hundred sixty-four titanium endosteal dental implants were placed in 51 subjects: 37 males and 14 females between the ages of 8 and 68 (mean age 20.5 years, median age 16.5 years). Two hundred forty-three implants were placed in the anterior mandible, and 21 were placed in the anterior maxilla with a 2-stage surgical protocol. Either fixed-detachable dentures or bar-clip overdentures were provided. Subjects were followed up for 0 to 78 months after second-stage surgery. Kaplan-Meier survival rates and curves were produced to describe the survival of the implants for the different age groups and implant locations. Repeated-measures Cox regression models were used to evaluate the hazard ratios for age and location, with alpha=.05 as the criteria for significance. RESULTS: Of the 243 implants placed in the anterior mandible, 221 (91%) survived. Of the 21 implants placed in the anterior maxilla, 16 (76%) survived. Fourteen of the 51 (27%) subjects had a failed implant. All but 2 failures occurred before or at second-stage surgery. Implant-supported prostheses were provided for all patients. CONCLUSION: Within the limitations of this study, the results support the continued use of endosteal dental implants in this patient population with appropriate precautions in the maxilla.     

Recombinant human transforming growth factor beta-1 and its effects on osseointegration

Dental implant failures are still a common occurrence, especially in areas of poor bone quality. The purpose of this study was to observe whether the application of a growth factor, recombinant human transforming growth factor beta-1 (rhTGF-beta1), would improve the healing of bone adjacent to titanium dental implants. Four adult male Yucatan minipigs had four titanium dental implants placed into the inferior border of each hemimandible. On the control side, the implants were placed in standard fashion. On the experimental side, rhTGF-beta1 within a carrier gel was placed into the recipient site before implant placement. After a 6-week healing period, two implants from each side were evaluated by pull-out testing and histomorphometric analysis. The mean pull-out force for experimental implants was 1,124.01 N and 818.12 N (P = 0.5015) for controls. The mean percentage of bone between adjacent threads on the implant surface was 49.74% for the experimental group and 36.50% for controls (P = 0.0783). The mean percentage of bone-implant surface contact was 41.86% for the experimental implant sites and 24.60% for the control implant sites (P = 0.0452). The application of rhTGF-beta1 to implant sites appears to increase the amount of bone healing adjacent to a titanium dental implants in minipig mandibles at the 6-week period. Further studies are required to quantify better the amount of growth factor required and to study its effects over a broader period of time to see whether these differences are maintained.