Ofer Mardinger

Characteristics of Early Versus Late Implant Failure: A Retrospective Study

PURPOSEnImplant failures can be divided into early and late according to the timing of failure. The purpose of this study was to characterize and compare both types.nnnPATIENTS AND METHODSnA retrospective cohort study was conducted in 194 patients (98 men and 96 women) who presented after dental implant failures during a 6-year period (2000 to 2006). The patient served as the unit of analysis. A history of at least 1 failed and removed dental implant served as the inclusion criterion. Patients were excluded from this study whenever their files had missing data. The collected data included a patients characteristics, failure characteristics, and the anatomic status of the alveolar ridge after failure.nnnRESULTSnLate failures were associated with moderate to severe bone loss, a larger number of failed implants per patient, a higher incidence in men, and mostly in posterior areas. Early failures were associated with minimal bone loss, occurred more in women, at a younger age, and in most cases the implants were intended to support single crowns.nnnCONCLUSIONSnMeticulous follow-up is needed to reveal and treat failing or ailing implants. Once established as hopeless, they should be removed as soon as possible to prevent further bone loss.

Analysis of Complications Following Augmentation With Cancellous Block Allografts

BACKGROUNDnBone grafting may be associated with soft and hard tissue complications. Recipient site complications encountered using cancellous block allografts for ridge augmentation are analyzed.nnnMETHODSnA total of 101 consecutive patients (62 females and 39 males; mean age 44 ± 17 years) were treated with implant-supported restoration of 137 severe atrophic alveolar ridges augmented with cancellous bone-block allografts. Alveolar ridge deficiency locations were classified as anterior maxilla (n = 58); posterior maxilla (n = 32 sinuses); posterior mandible (n = 32); and anterior mandible (n = 15). A total of 271 rough-surface implants were placed. Recipient site complications associated with block grafting (infection, membrane exposure, incision line opening, perforation of mucosa over the grafted bone, partial graft failure, total graft failure, and implant failure) were recorded.nnnRESULTSnPartial and total bone-block graft failure occurred in 10 (7%) and 11 (8%) of 137 augmented sites, respectively. Implant failure rate was 12 (4.4%) of 271. Soft tissue complications included membrane exposure (42 [30.7%] of 137); incision line opening (41 [30%] of 137); and perforation of the mucosa over the grafted bone (19 [14%] of 137). Infection of the grafted site occurred in 18 (13%) of 137 bone blocks. Alveolar ridge deficiency location had a statistically significant effect on the outcome of recipient site complications. More complications were noted in the mandible compared to the maxilla. Age and gender had no statistically significant effect.nnnCONCLUSIONSnFailures caused by complications were rarely noted in association with cancellous block grafting. The incidence of complications in the mandible was significantly higher. Soft tissue complications do not necessarily result in total loss of cancellous block allograft.

Cancellous Bone Block Allografts for the Augmentation of the Anterior Atrophic Maxilla

BACKGROUNDnPre-implant augmentative surgery is a prerequisite in many cases in the anterior maxilla to achieve a stable, long-term esthetic final result.nnnPURPOSEnThe aim of the present study was to evaluate the outcome of ridge augmentation with cancellous freeze-dried block bone allografts in the anterior atrophic maxilla followed by placement of dental implants.nnnMATERIALS AND METHODSnThirty-one consecutive patients were included in the study. A bony deficiency of at least 3 mm horizontally and up to 3 mm vertically according to computerized tomography (CT) served as inclusion criteria. Sixty-three implants were inserted after a healing period of 6 months. Nineteen of sixty-three implants were immediately restored. Bone measurements were taken prior to bone augmentation, during implant placement, and at second-stage surgery.nnnRESULTSnForty-six cancellous allogeneic bone blocks were used. The mean follow-up was 34 ± 16 months. Mean bone gain was 5 ± 0.5 mm horizontally, and 2 ± 0.5 mm vertically. Mean buccal bone resorption was 0.5 ± 0.5 mm at implant placement, and 0.2 ± 0.2 mm at second-stage surgery. Mean bone thickness buccal to the implant neck was 2.5 ± 0.5 mm at implant placement, and 2.3 ± 0.2 mm at second-stage surgery. There was no evidence of vertical bone loss between implant placement and second-stage surgery. Block and implant survival rates were 95.6 and 98%, respectively. All patients received a fixed implant-supported prosthesis.nnnCONCLUSIONnCancellous block allografts appear to hold promise for grafting the anterior atrophic maxilla.

Late signs and symptoms of maxillary sinusitis after sinus augmentation

OBJECTIVESnThe aim of this study was to assess the incidence of late signs and symptoms of acute and chronic maxillary sinusitis after sinus augmentation and to correlate them with predisposing factors.nnnSTUDY DESIGNnA total of 137 individuals (54 male and 83 female; 153 sinus augmentation procedures) were evaluated retrospectively for signs and symptoms of maxillary sinusitis, 12-80 months after surgery, using a questionnaire and clinical and radiographic examinations.nnnRESULTSnThe incidence of acute and chronic sinusitis after sinus augmentation was low (<5%). History of preoperative sinusitis (P = .001) and sinuses with thick mucosa (P < .0001) were statistically significant factors correlated with late signs and symptoms of sinusitis. There was a slight correlation between chronic sinusitis and women (P = .079) or 2-stage procedures (P = .098). There was no statistical correlation to intraoperative complications, such as membrane perforation and excessive bleeding.nnnCONCLUSIONSnThe occurrence of postoperative chronic sinusitis appears to be limited to patients with history of preoperative sinusitis and sinuses with thick mucosa, despite control of the disease before sinus augmentation. Intraoperative surgical complications have negligible effect. Patients presenting with preoperative sinusitis and sinuses with thick mucosa need to be informed of the increased risk. They require a close follow-up and prompt treatment in the event of signs and symptoms of sinusitis.

Implant-supported restoration of congenitally missing teeth using cancellous bone block-allografts

BACKGROUND AND OBJECTIVEnPatients with congenitally missing teeth may present with undeveloped alveolar bone morphology, making implant reconstruction a challenge. The aim of the present study was to evaluate the outcome of dental implants after ridge augmentation with cancellous freeze-dried block bone allografts in patients with congenitally missing teeth.nnnSTUDY DESIGNnTwelve patients with a mean age of 21 ± 4 years, were included. Congenitally missing teeth included maxillary lateral incisors, a maxillary canine, and mandibular central and lateral incisors. A bony deficiency of ≥3 mm horizontally and ≤3 mm vertically according to computerized tomography served as inclusion criteria. Twenty-one implants were inserted after a healing period of 6 months. Five out of 21 implants were immediately restored. Bone measurements were taken before bone augmentation, during implant placement, and at second-stage surgery.nnnRESULTSnNineteen cancellous allogeneic bone-blocks were used. The mean follow-up time was 30 ± 16 months. Bone block and implant survival rates were 100% and 95.2%, respectively. Mean bone gain was statistically significant (P < .001): 5 ± 0.5 mm horizontally and 2 ± 0.5 mm vertically. All of the patients received a fixed implant-supported prosthesis. Soft tissue complications occurred in 4 patients (30%). Complications after cementation of the crowns were seen in 1 implant (4.8%). All implants remained clinically osseointegrated at the end of the follow-up examination. There was no crestal bone loss around the implants beyond the first implant thread.nnnCONCLUSIONnCancellous bone block-allografts can be used successfully for implant-supported restorations in patients with congenitally missing teeth.

Histomorphometric analysis following augmentation of the posterior mandible using cancellous bone-block allograft

The present study was conducted to histologically and histomorphometrically evaluate the application of cancellous bone-block allografts for the augmentation of the posterior atrophic mandible. Twenty-four consecutive patients underwent augmentation with cancellous bone-block allografts in the posterior mandible. A bony deficiency of at least 3 mm horizontally and/or vertically according to CT para-axial reconstruction served as inclusion criteria. Following 6 months, 85 implants were placed and a cylindrical sample core was collected. All specimens were prepared for histological and histomorphometrical examination. Implant survival rate was 95.3%. Follow-up ranged 12-66 months (mean 43 ± 19 months). The mean newly formed bone was 44 ± 28%, that of the residual cancellous bone-block allograft 29 ± 24%, and of the marrow and connective tissue 27 ± 21%. Statistically significant histomorphometric differences regarding newly formed bone (69% vs. 31%, p = 0.05) were found between younger (< 45 years) and older (> 45 years) patients, respectively. Histomorphometric differences regarding residual cancellous bone-block allograft (17% vs. 35%) and of the marrow and connective tissue (14% vs. 34%) were not statistically significant. Cancellous bone-block allograft is biocompatible and osteoconductive, permitting new bone formation following augmentation of extremely atrophic posterior mandible with a two-stage implant placement procedure. New bone formation was age-dependent.

Factors affecting changes in sinus graft height between and above the placed implants

OBJECTIVEnThe aim of this study was to compare the radiographic dimensional changes of sinus graft height above and between placed implants, and evaluate the factors effecting these changes with 2 different grafting materials and both combination.nnnSTUDY DESIGNnThe study group comprised 42 patients (50 sinus augmentation procedures). Four consecutive panoramic radiographs were evaluated for changes in sinus graft height between and above the placed implants. Factors that may influence graft height reduction were evaluated.nnnRESULTSnThe mean percentage of autogenous bone height reduction was 23% between implants and 13% above the implants. Bovine xenograft showed a mean of 6.5% graft height reduction between implants and 0% above implants. The only 2 parameters that correlated with reduction of graft height above and between the implants were time elapsed from surgery and the type of bone graft. Autogenous bone graft presented significantly more reduction (P = .022), whereas anorganic bovine bone graft had only minor or no changes in height.nnnCONCLUSIONnThe most important factor influencing reduction in vertical bone height on the time axis, following sinus augmentation is the grafting material, followed by the presence of a functional implant. Anorganic bovine bone was found superior in graft height maintenance in an up to 10 years of follow-up.

A retrospective analysis of replacing dental implants in previously failed sites

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

Post-Traumatic Implant-Supported Restoration of the Anterior Maxillary Teeth Using Cancellous Bone Block Allografts

PURPOSEnTo prospectively evaluate the outcome of dental implants placed in the post-traumatic anterior maxilla after ridge augmentation with cancellous freeze-dried block bone allografts.nnnMATERIALS AND METHODSnPatients presenting with a history of anterior dentoalveolar trauma with bony deficiencies in the sagittal (≥3 mm) and vertical (<3 mm) planes according to computed tomography were included. The recipient sites were reconstructed with cancellous bone block allografts. After 6 months of healing, implants were placed. The primary outcomes of interest were 1) bone measurements taken before grafting, at the time of implant placement, and at stage 2 operations; 2) implant survival; and 3) complications.nnnRESULTSnThe sample was composed of 20 consecutive patients with a mean age of 25 ± 7 years. We used 28 cancellous allogeneic bone blocks, and 31 implants were inserted. Of the 31 implants, 12 were immediately restored. The mean follow-up was 42 ± 15 months. Graft and implant survival rates were 92.8% and 96.8%, respectively. Mean bone gain in the sagittal and vertical planes was 5 ± 0.5 mm horizontally and 2 ± 0.5 mm (P < .001). Successful restoration was achieved in all patients with fixed implant-supported prostheses. Soft tissue complications occurred in 7 patients (35%). Complications after cementation of the crowns were seen in 3 implants (9.6%). All implants remained clinically osseointegrated at the end of the follow-up examination. There was no crestal bone loss around the implants beyond the first implant thread.nnnCONCLUSIONnCancellous block allograft can be used successfully for post-traumatic implant-supported restoration in the anterior maxilla.

Intrasocket reactive soft tissue for primary closure after augmentation of extraction sites with severe bone loss before implant placement.

PURPOSEnThe normal bone resorption after tooth extraction can be significantly aggravated in the case of pre-existing severe bone loss and chronic infection. Bone augmentation procedures have been proposed, but they require adequate closure of soft tissues. We propose the use of intrasocket reactive tissue to cover extraction sites augmented by bovine bone mineral graft to promote the success of the graft procedure.nnnPATIENTS AND METHODSnThe study included 24 patients with severe bone loss and chronic pathology in 27 sites. The intrasocket reactive soft tissue was elevated from the bony walls in a subperiosteal plane. Porous bovine or allograft bone mineral was placed in the extraction site without membranes, and the intrasocket reactive soft tissue was sutured over the grafting material to seal the coronal portion of the socket. Twenty-seven implants were placed 6 months after bone augmentation.nnnRESULTSnHealing progressed uneventfully. Postoperative morbidity was minimal. There was no leakage or infection of the grafting material. The mean time to implant placement was 7.8 months. Supplemental augmentation was not needed. There were no implant failures. Follow-up ranged from 6 to 36 months (mean, 15 months). All implants were rehabilitated with fixed prostheses.nnnCONCLUSIONSnIntrasocket reactive soft tissue can be used predictably to obtain primary closure of augmented extraction sites with severe bone loss with minimal postoperative morbidity.