Indications for implant-supported rehabilitation of the posterior atrophic maxilla: A multidisciplinary consensus among experts in the field utilising the modified Delphi method.

PURPOSE: To establish consensus-driven guidelines that could support the clinical decision-making process for implant-supported rehabilitation of the posterior atrophic maxilla and ultimately improve long-term treatment outcomes and patient satisfaction. MATERIALS AND METHODS: A total of 33 participants were enrolled (18 active members of the Italian Academy of Osseointegration and 15 international experts). Based on the available evidence, the development group discussed and proposed an initial list of 20 statements, which were later evalu-ated by all participants. After the forms were completed, the responses were sent for blinded ana-lysis. In most cases, when a consensus was not reached, the statements were rephrased and sent to the participants for another round of evaluation. Three rounds were planned. RESULTS: After the first round of voting, participants came close to reaching a consensus on six statements, but no consensus was achieved for the other fourteen. Following this, nineteen statements were rephrased and sent to participants again for the second round of voting, after which a consensus was reached for six statements and almost reached for three statements, but no consensus was achieved for the other ten. All 13 statements upon which no consensus was reached were rephrased and included in the third round. After this round, a consensus was achieved for an additional nine statements and almost achieved for three statements, but no consensus was reached for the remaining statement. CONCLUSION: This Delphi consensus highlights the importance of accurate preoperative planning, taking into consideration the maxillomandibular relationship to meet the functional and aesthetic requirements of the final restoration. Emphasis is placed on the role played by the sinus bony walls and floor in providing essential elements for bone formation, and on evaluation of bucco-palatal sinus width for choosing between lateral and transcrestal sinus floor elevation. Tilted and trans-sinus implants are considered viable options, whereas caution is advised when placing pterygoid implants. Zygomatic implants are seen as a potential option in specific cases, such as for completely edentulous elderly or oncological patients, for whom conventional alternatives are unsuitable.

Apical and marginal bone alterations around implants in maxillary sinus augmentation grafted with autogenous bone or bovine bone material and simultaneous or delayed dental implant positioning.

OBJECTIVE: A re-pneumatization phenomenon was recorded in sinuses grafted with different materials. The specific aims of this paper were to assess the dental implant survival rate and the behavior of marginal and apical bone remodeling around dental implants placed following sinus augmentation. MATERIALS AND METHODS: A retrospective study was conducted on consecutive patients treated in two surgical centers. Different surgical techniques were adopted for sinus augmentation: simultaneous or delayed dental implant insertion with bovine bone-material augmentation or autologous bone grafting (chin and iliac crest). Survival rates were recorded for the overall number of implants (patients of group A). Apical and marginal bone levels (ABL and MBL, respectively) were radiographically measured, and statistical analysis was performed in implants of a subgroup of patients (group B). RESULTS: A total of 282 dental implants were positioned. Recorded cumulative survival rates (CSRs) were 95.6% and 100% for autogenous and bovine bone material, respectively, while CSRs at 2-year follow-up for immediate and delayed procedures were 99.3% and 96.5%. For the subgroup B, 57 sinus augmentation procedures were performed in 39 patients, with the positioning of 154 implants. Generally, the apical- and marginal-bone resorption of the bovine bone-material group was less than that of the autogenous group. The differences between the ABL values of the bovine bone-material and iliac-crest groups were statistically significant at 1 year, whereas this significance disappeared at the 2-year follow-up; tests showed that a statistical difference was recorded in the bovine bone-material group between the 1- and 2-year follow-ups. With regard to MBL comparisons between simultaneous and delayed implantation, the differences maintained their significance at the 2-year follow-up also. CONCLUSIONS: Differences regarding apical bone alteration between autogenous bone from the iliac crest and bovine bone material at the 1- and 2-year follow-ups, as well as in the bovine bone-material group between the 1- and 2-year follow-ups, attested to slower but more prolonged physiologic bone remodeling in the bovine-graft-material group than in the autogenous-bone group. The MBL analysis showed that remodeling in the delayed implant group demonstrated a greater resorption in the cervical portion than was seen in the simultaneous implant group.

Bisphosphonate-related osteonecrosis of the jaw associated with dental implants.

PURPOSE: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a well-documented devastating side effect of long-term bisphosphonate (BP) use. There is scarce information in the literature on BRONJ associated with dental implants (DIs). The purpose of this study was to present a large series of cases of this association. PATIENTS AND METHODS: The files of all patients with BRONJ associated with DIs who were treated in the department of oral and maxillofacial surgery from 2003 to 2009 were reviewed. Data on demographics, medical background, type, and duration of BP treatment before the development of BRONJ, mode of therapy, and therapeutic outcome were retrieved. RESULTS: Of the 27 patients enrolled into the study, 11 (41%) developed BRONJ while taking oral BPs and 16 (59%) developed BRONJ associated with intravenous BPs. BRONJ developed after mean periods of 68 months (median, 60), 16.4 months (median, 13), and 50.2 months (median, 35) in patients on alendronate, zoledronic acid, and pamidronate, respectively. Only 6 patients developed BRONJ during the first 6 months after DI placement. When BP treatment had been started before DI placement, there was a mean duration of 16.2 months (median, 11) until the appearance of BRONJ development. Long-term antibiotics and only essential surgical procedures comprised the treatment of choice, and the response rate was considerably better for patients taking the oral type of BPs. There was no significant association between BRONJ and diabetes, steroid intake, or smoking habits. CONCLUSION: Patients undergoing BP treatment and who receive DIs require a prolonged follow-up period to detect any development of BRONJ associated with DIs.

Symphysis revisited: clinical and histologic evaluation of newly formed bone and reharvesting potential of previously used symphysial donor sites for onlay bone grafting.

BACKGROUND: This article reports on the reharvesting potential of newly formed bone in previously used symphysial donor sites. METHODS: This study included five patients who were scheduled for sequential onlay bone augmentations prior to dental implant placement using the symphysis area as a donor site. At 5 months after bone augmentation, computed tomography scans of donor sites revealed healing from the first surgery. Because additional bone augmentation was required, the same sites were revisited for bone harvesting. Reharvesting was performed 5 months after the first harvesting. A small portion of the harvested bone from two patients was evaluated histologically. RESULTS: Five months postharvesting, clinical observation of the donor sites resembled newly formed bone as a conglomerate of bovine bone particles. In the five patients, bone continuity was observed between new bone at the donor defect sites and surrounding bone. Additional blocks were reharvested from the same sites and successfully grafted to recipient sites. Dental implants were inserted 5 months after the second augmentation, which healed uneventfully. Histologically, bovine bone particles were surrounded by woven bone, with areas of mature bone with well-organized osteons. CONCLUSIONS: Remodeling of a symphysial donor area enabled reuse of the site for additional harvesting. Intraoral bone sources could serve as a long-lasting renewable source of high-quality bone.

Metal Nanoparticles Released from Dental Implant Surfaces: Potential Contribution to Chronic Inflammation and Peri-Implant Bone Loss.

Peri-implantitis is an inflammatory disease affecting tissues surrounding dental implants. Although it represents a common complication of dental implant treatments, the underlying mechanisms have not yet been fully described. The aim of this study is to identify the role of titanium nanoparticles released form the implants on the chronic inflammation and bone lysis in the surrounding tissue. We analyzed the in vitro effect of titanium (Ti) particle exposure on mesenchymal stem cells (MSCs) and fibroblasts (FU), evaluating cell proliferation by MTT test and the generation of reactive oxygen species (ROS). Subsequently, in vivo analysis of peri-implant Ti particle distribution, histological, and molecular analyses were performed. Ti particles led to a time-dependent decrease in cell viability and increase in ROS production in both MSCs and FU. Tissue analyses revealed presence of oxidative stress, high extracellular and intracellular Ti levels and imbalanced bone turnover. High expression of ZFP467 and the presence of adipose-like tissue suggested dysregulation of the MSC population; alterations in vessel morphology were identified. The results suggest that Ti particles may induce the production of high ROS levels, recruiting abnormal quantity of neutrophils able to produce high level of metalloproteinase. This induces the degradation of collagen fibers. These events may influence MSC commitment, with an imbalance of bone regeneration.

Morphologic changes of the nasopalatine canal related to dental implantation: a radiologic study in different degrees of absorbed maxillae.

BACKGROUND: Implant rehabilitation of the edentulous anterior maxilla remains a complex restorative challenge. Intricate preexisting anatomy dictates meticulous and accurate osteotomy planning. With progressive bone loss, the alveolar crest may approach anatomic structures. The nasopalatine nerve and vessels may ultimately emerge from the ridge crest. The radiologic changes of the nasopalatine canal were evaluated in different resorption phases of the premaxilla alveolus with regard to dental implantation. METHODS: The study consisted of 207 subjects who had maxillary computed tomography scans before dental implantation. The Lekholm and Zarb classification was used to divide images according to the residual bony ridge: Class A (control group) and classes B to E (study group). Anatomic mapping of the nasopalatine canal structure was carried out in both groups. RESULTS: The canal diameter was wider along the degree of ridge resorption from classes A to E in all dimensions, mainly in the palatal opening (P <0.01), middle area (P <0.001), and nasal area. The mean diameter of the enlargement was 1.8 mm, which reached 5.5 +/- 1.08 mm (P <0.01) in type E bone. In the severely resorbed ridges (classes C through E), when the palatal opening was situated on the ridge, it occupied a mean of 35.6% (13% to 58%) of the area devoted to implant placement. Tooth loss was the main reason for ridge resorption (P <0.01). CONCLUSIONS: Canal diameter enlargement was greater anteriorly to the ridge and posteriorly to the palatal bone, mainly because of tooth extraction. The atrophy of disuse may influence surrounding structures, similar to the maxillary sinus tendency to expand into surrounding bone mainly after tooth loss.

Failure causes, timing, and cluster behavior: an 8-year study of dental implants.

OBJECTIVES: The aim of this study was to analyze implant failure, causes, time of failure, and cluster behavior of implant failure among patients referred to a private surgical center. METHODS: All failed implants placed during the years 1997-2004 were analyzed. Data collected included age, gender, smoking habits, implant type and dimensions, timing of implantation (immediate or nonimmediate), time to failure, and failure causes. RESULTS: Overall, 99 of the 3609 implants placed between the years 1997 and 2004 failed in 61 patients resulting in a 97.3% survival rate. Patients with implant failure ranged in age from 21 to 78 years (average 54 years); 34% were men, 66% women; smoking was reported by 32.8%, pastsmoking 16.4%; time from implant placement to failure ranged from 1 to 99 months (average 24 months, SD = 24.8). Common causes for implant removal were bone loss and/or inflammation (52.5%), and implant mobility (43.4%). Cluster behavior (ie, more than one implant failure per patient, not necessarily in the same area or quadrant) was shown in one-third (32.8%) of the patients in which 56.6% of all failures were found. This cluster pattern was evident in both the surgical and prosthetic phase failures. CONCLUSION: There is a higher probability for a cluster pattern among patients with implant failure. Common signs for failure are implant mobility (surgical phase) and infection and marginal bone loss (prosthetic phase).

Long-term marginal bone loss around single dental implants affected by current and past smoking habits.

PURPOSE: To compare the long-term marginal implant bone loss, survival, and radiographic success of single dental implants among current, past smokers, and nonsmokers. PARTICIPANTS AND METHODS: The study was based on a consecutive cohort of patients who received single implants between 2 adjacent natural teeth. Only implants with 5 or more years follow-up were considered with no less than 3 follow-up radiographs at different time points with at least 1 year interval between radiographs. All radiographs were analyzed for changes in marginal bone loss. RESULTS: The study consisted of 64 patients, ranging in age from 18 to 78 (mean, 45 years) with a total of 64 single implants. Average follow-up time was 6.14 years (range, 5-14). Success rate was 93.75%; 4 implant failed. Two of the failures were due to mechanical neck brake and 2 resulted from peri-implantitis and bone loss. Survival rates were not related to smoking habits. The mean marginal bone loss measured for all implants was 0.145 mm during the first year, 0.07 mm per year during years 1 throughout 5 and 0.026 mm per year from the sixth year till the end of follow-up. Current smokers demonstrated higher marginal bone loss during all time intervals than former smokers and both demonstrated higher marginal bone loss during all time intervals than nonsmokers. CONCLUSION: Our results reaffirm the relation between smoking and peri-implant bone loss. Former smokers still demonstrated an increase in marginal bone loss as compared with nonsmokers. There was no difference in implant survival in relation to smoking habits.

Success of dental implants placed in intraoral block bone grafts.

BACKGROUND: The purpose of this study was to evaluate the survival and success of dental implants placed in alveolar bone following augmentation using intraoral block bone grafts. METHODS: A consecutive retrospective study was conducted on patients who had onlay bone grafts for vertical or horizontal augmentations followed by dental implantation from 1999 to 2001. Files of 50 healthy patients who received 129 implants in augmented sites were reviewed. Implant survival, radiologic implant success (marginal bone loss), and complications were recorded. RESULTS: Follow-up from time of implantation ranged from 6 to 67 months (mean: 24.3 +/- 11.2 months). Ranges of implant widths and lengths were 3.25 to 4.7 mm and 10 to 16 mm, respectively. The overall survival rate was 96.9% (four implants were removed). Marginal bone loss around implants ranged from 0 to 3.3 mm (average: 0.22 +/- 0.45 mm). Only 5% of the implants presented marginal bone loss > or =1.5 mm over the follow-up time. CONCLUSIONS: Intraoral bone block graft surgery is a predictable operation for the use of dental implants. Implant placement in augmented areas presents high survival and radiologic success rates with minimal bone loss.

Survival of immediately provisionalized dental implants placed immediately into fresh extraction sockets.

BACKGROUND: The aim of this study was to evaluate the survival rate of immediately provisionalized dental implants immediately placed into fresh extraction sockets. METHODS: The study consisted of 87 consecutive patients, ranging in age from 21 to 76 years (average: 53.30 +/- 13.34 years), who received 210 immediately provisionalized, immediately placed dental implants between the years 2000 and 2005. Data were recorded regarding the survival rate of these implants and the incidence of complications. RESULTS: Follow-up ranged from 6 to 52 months (mean: 15.60 +/- 12.60 months). Smoking, past and present, was reported by 28.7% and 20.7% of patients, respectively. The maxillary incisors were replaced most frequently, followed by the mandibular lateral incisors. Most of the implants were >13 mm in length and > or = 3.75 mm in diameter. There were 47 (22.4%) single restored implants and 163 (77.6%) splinted implants. Overall, the implant survival rate was 97.6% (five implants failed). Complications, such as swelling, inflammation, and pain, were observed in 24 (11.4%) of the implants. No relation was found between complications and failure. The present study failed to reveal a relationship between implant survival rate and smoking, implant dimensions, and area of implantation. CONCLUSION: Immediately provisionalized immediate implants can serve as a predictable procedure with high survival rates.

Inter-implant bone height changes in anterior maxillary immediate and non-immediate adjacent dental implants.

BACKGROUND: The purpose of this study was to evaluate inter-implant bone crest height changes between immediate and non-immediate dental implants placed in the anterior maxillary region. METHODS: A retrospective study was conducted on consecutively treated patients requiring at least two adjacent implants in the anterior maxillary region that were placed in the same operation during 1994 to 2004. Files of 45 healthy patients reporting 200 implants were reviewed. Age, gender, smoking status, and implant characteristics (coating and dimensions) were recorded. Inter-implant bone measurements were taken on two panoramic radiographs from each patient: one after implant placement and the other at the last follow-up. The distance between adjacent implants was measured at the implant-abutment interface (implant platform). RESULTS: Overall, 130 inter-implant gaps were found. Follow-up ranged from 8 to 146 months. Two-tailed Pearson correlation tests revealed a negative correlation between inter-implant distance and bone loss (P = 0.036). Mean peak-crest bone loss for immediate implants was higher than for delayed implants (P = 0.026). There was more bone loss when hydroxyapatite (HA)-coated implants were used, although no statistical significance was observed. No statistically significant difference was found between the different locations in the anterior maxilla. No correlation was found between patient's age, smoking habits, and bone loss or between follow-up time and bone loss. CONCLUSIONS: A negative correlation was found between inter-implant distance and bone loss at the inter-implant bone crest in the anterior maxillary region. Bone loss was small in this study cohort.

Denture-related osteonecrosis of the maxilla associated with oral bisphosphonate treatment.

BACKGROUND: Bisphosphonates are a class of agents used to treat various systemic conditions. Despite the benefits of bisphosphonates, osteonecrosis of the jaws is an important complication in a subset of patients who receive this drug treatment. CASE DESCRIPTION: A 66-year-old woman was referred to an oral surgeon at a private surgical center because of a pressure wound in the margins of a removable maxillary denture. The patient reported that she had received oral alendronate sodium treatment for eight years. A clinical examination revealed a palatal ulcer with exposed necrotic gray bone at its center. The clinician performed an excisional biopsy and separated two palatal rotational flaps to enable an adequate blood supply to reach the operated-on area. CLINICAL IMPLICATIONS: This report, together with growing evidence in the literature, serves to alert treating physicians and dental practitioners about the potential complication of maxillary and mandibular bone necrosis in patients receiving bisphosphonate therapy.

Interpretations of complications following third molar extraction.

OBJECTIVE: Surgical removal of third molars is often associated with complications. The aim of the present study was to analyze the incidence of complications following extraction of third molars relative to the risk factors. METHOD AND MATERIALS: This retrospective study included 463 patients who had mandibular third molar extraction (performed by a single surgeon, DSA) in the years 2001 to 2011. In total, 665 mandibular third molars were extracted. The average patient's age was 29 ± 11.30 years, median 26 years, and the patient age ranged from 13 to 75 years. Patients' records were obtained for medical/general data. RESULTS: The overall prevalence of postsurgical complications was 17%. Dry sockets showed the highest incidence (11.6%). Partially impacted teeth showed the highest incidence of complications (67.3%). Cigarette smoking correlated with increased complications and dry sockets, and complications were more prevalent on the left side (62.8%). CONCLUSION: Complications after mandibular third molar extraction increase with age, level of impaction, side of extraction, and cigarette smoking.

Long-term success of implants replacing a single molar.

BACKGROUND: The aim of this study was to assess the long-term success and survival rates of implants replacing a single molar between two natural teeth and to evaluate the influence of implant characteristics on implant success. METHODS: The study was based on a consecutive cohort of 81 patients who received implants to replace a single molar between the years 1994 and 2004. Inclusion criteria for patients were having an implant replacing a molar between two natural teeth and follow-up data of at least 6 months. Data were recorded regarding the incidence of complications and success and survival rates of these implants. RESULTS: The range of follow-up was from 6 to 125 months (mean: 36 months). Smoking was reported by 18.5% of patients. The replacement of a mandibular molar was more frequent (87.7%), with 25.9% of the implants placed immediately after tooth extraction. Two implants were used to replace a single molar in seven patients (8.6%). The failure rate was 7.4% (six implants failed: three had broken necks, and three failed because of infection or bone loss). Complications included suppuration in 11.1% of implants and a pocket around the implant in two patients (2.5%). No relation was found among failure, complications, timing of implant placement, and smoking habits. CONCLUSION: A single implant can serve as a good long-term and predictable treatment modality to replace a single molar with low complication and failure rates.

Retrospective evaluation of surgical endodontic treatment: traditional versus modern technique.

The aim of this retrospective study was to compare the outcome of surgical endodontic treatment preformed using the traditional versus modern techniques. There were 110 patients who were treated by surgical endodontic treatment between 2000 and 2002 and evaluated from their dental charts. The surgical endodontic treatment was preformed using a traditional or modern technique. The traditional technique included root-end resection with a 45 degrees bevel angle, and retrograde preparation using a carbide round bur. The modern technique included root-end resection with minimal or no bevel, and retrograde preparation using ultrasonic retro-tips with the aid of a dental operating microscope. The retrograde filling material for both techniques was intermediate restorative material. There were 71 patients with 88 treated teeth that were compatible with the inclusion criteria. Complete healing rate for the teeth treated with the modern technique (91.1%) was significantly higher than that for teeth treated using the traditional technique (44.2%) (p < 0.0001). In the traditional technique a significant (p = 0.032) negative influence of the tooth type was found. Modern surgical endodontic treatment using operative microscope and ultrasonic tips significantly improves the outcome of the therapy compared to the traditional technique.

Implant marginal bone loss in maxillary sinus grafts.

PURPOSE: The marginal bone loss (MBL) around implants placed in maxillary sinus grafts was evaluated. MATERIALS AND METHODS: The study consisted of 70 patients who had undergone 81 sinus-graft procedures (total 212 screw-type implants). Complete radiographic records were available for 160 implants, which were used to calculate MBL (follow-up 6 to 56.5 months). Habits (smoking, bruxism), surgical phase parameters (preoperative residual bone, grafting material, implant characteristics, and complications), and prosthetic parameters (crown-implant ratio, marginal fit, and opposite-arch restoration) were recorded for each patient and statistically analyzed regarding MBL. RESULTS: Cumulative survival and overall radiographic success rates were 95.5% and 83.7% for 4.5 years, respectively. Smoking, small implant surface area, and a delayed implantation approach were related to enhanced MBL, with mean MBL values of 0.24 mm/y (P < .011), 0.21 mm/y (P < .031), and 0.31 mm/y (P = .052), respectively. In residual bone of < or =4 mm, the relation to enhanced MBL was stronger (P < .018) for delayed implantation. DISCUSSION: Survival and radiographic success rates compare well with other reports. However, most studies modify success criteria regarding MBL. Smoking may be a primary risk factor regarding implant success. Implants with greater surface area values could compensate for problematic bone characteristics (e.g., in grafted maxillary sinuses). The effect of delayed implantation on MBL was surprising and may prompt simultaneous implantation whenever primary stability can be achieved. CONCLUSIONS: Smoking and implant surface area affected MBL in this patient population. Criteria for long-term implant success should be revised to a standard.

Long Term Follow-Up of Dental Implants Placed in Autologous Onlay Bone Graft.

PURPOSE: The aim of this study was to evaluate the efficacy of autologous intraoral onlay bone grafting (OBG) in correlation with long-term survival rates of dental implants placed in the augmented bone. MATERIALS AND METHODS: A retrospective study was conducted on 214 patients who received a total of 633 dental implants placed in 224 autologous intraoral block OBG augmentations, combined with Bio-Oss - mixed with platelet-rich plasma (PRP) and covered by platelet-poor plasma (PPP) - as scaffold, with a follow-up time up to 137 months (mean 39.9 ± 30.9 months). RESULTS: A total of 216 OBG cases were successful (96.4%), and most of the augmentations were uneventful (88.4%). Bone graft exposure was moderately associated with bone graft failure (χ(2) = 3.76, p = .052). The healing period after implant placement was 4-6 months (mean 5.6 ± 2.56). The majority of the 591 implants survived (93.4%). The cumulative survival rate of the implants was 83%. CONCLUSIONS: We suggest that augmentation of severely atrophied jaw bone through the placement of horizontal and/or vertical intraoral OBGs in combination with Bio-Oss saturated with PRP and covered by PPP should be considered a reliable, safe, and very effective surgical technique for obtaining high bone graft survival rate and high long-term implant survival rate.

Intraoral autogenous block onlay bone grafting for extensive reconstruction of atrophic maxillary alveolar ridges.

BACKGROUND: Endosseous implants require sufficient bone volume for complete bone coverage. Alveolar deficiency can prevent ideal implant placement. Local bone grafts are a convenient source of autogenous bone in alveolar reconstruction. The aim of this study was to describe a technique, and to evaluate the success of extensive bone reconstruction of atrophic maxillary alveolar ridges using only intraoral block bone grafts prior to dental implantation. METHODS: Files of 10 healthy patients with extensive bone reconstruction of the maxillary alveolar ridge using intraoral block bone graft operations were reviewed. Medical history, smoking status, bone origin (donor sites), number of bone blocks, and complications were recorded. RESULTS: Of the 10 extensive bone maxillary reconstructions, four were uneventful, two required additional bone augmentation at the time of dental implant placement, two had a minimal graft exposure, one had a minor adverse effect (temporary paresthesia), and one operation partially failed and required partial graft removal. CONCLUSION: Intraoral bone block grafting is a predictable operation with a high success rate for long-span augmentation, up to complete jaw augmentation/ extensive bone reconstruction of the maxillary alveolar ridge.

A long-term study of implants supporting overdentures as a model for implant success.

BACKGROUND: Implant-supported overdentures have been a common treatment for edentulous patients for the past 20 years, achieving good clinical results. The purpose of this study was to examine survival and success rates of implants supporting overdentures in the maxilla and mandible and to examine the influence of factors related to patients, implant procedure, implant data, and follow-up period on implant success. METHODS: During a 10-year period (1990 to 2000), 285 implants were placed in 62 patients to support 69 overdentures (seven patients had overdentures in both jaws). Patients ranged in age from 45 to 85 years (mean 64.5 years). The files of 61 patients, including 277 implants supporting 68 overdentures (14 maxillary and 54 mandibular), had measurable radiographic post-exposure follow-up (range 6.63 to 110.93 months, mean 37.93 months) for cervical bone loss (CBL) measurements. Bone loss was measured by radiographic examination in which the mean number of exposed threads in mesial and distal sides of the implant was considered. Implants were rehabilitated by overdentures with bar (N = 52) or ball (N = 16) attachments. RESULTS: Implant survival rate was 96.1% (11/285 did not survive) and total 10-year cumulative survival rate was 95.4% (maxilla, 83.5%, mandible, 99.5%). The success rate was 70.4% (maxilla, 41.9%; mandible, 80.8%) when using Albrektsson et al. success criteria. A logistic regression analysis showed that the maxilla (P <0.0001) and a short follow-up period (up to 5 years) (P = 0.017) were the most influencing factors enhancing CBL. CONCLUSIONS: 1) Survival of implants supporting overdentures was very high; 2) implants supporting overdentures in the maxilla had greater CBL than in the mandible; and 3) new criteria of implant success should be considered.

Evaluation of long-term implant success.

Implant success criteria, regarding marginal bone loss and other parameters, were first suggested in 1986 and today are still frequently referred to as the gold standard for implant success. However, according to the recent abundance of data on marginal bone loss and a better understanding of bone and soft tissue behavior around the implant neck and body, these criteria are inaccurate for the wide variety of implant systems. The purpose of this article is to review some of the relevant literature regarding marginal bone loss and to propose guidelines for a novel approach to evaluate the long-term success of implants regarding marginal bone loss. Four hypothetical patterns of implant marginal bone loss after the first year are suggested: a low-rate marginal bone loss over the years (Albrektsson's pattern); low-rate marginal bone loss in the first few years followed by a rapid loss of bone support; high-rate marginal bone loss in the first few years followed by almost no bone loss; and continuous high-rate marginal bone loss leading to a complete loss of bone support.