Ongoing Crestal Bone Loss around Implants Subjected to Computer-Guided Flapless Surgery and Immediate Loading Using the All-on-4® Concept.

BACKGROUND: The All-on-4(®) concept is widely applied for full-arch rehabilitations, using two tilted and two axially loaded implants in order to overcome anatomical constraints. PURPOSE: The aim of this study was to assess the survival and individual success of implants immediately loaded with an All-on-4 full-arch screw-retained prosthetic bridge in fully edentulous mandibles or maxillae over up to 3 years. MATERIALS AND METHODS: In total, 20 patients with atrophic jaws (9 maxillae, 11 mandibles) were treated with computer-guided flapless surgery and immediately provided with a provisional bridge. The final prosthesis was delivered after 6 months. In total, 80 TiUnite(™) Brånemark implants were placed. Radiographs were taken after surgery and 1 and 3 years later. RESULTS: A 3-year survival rate of 100% was seen for all implants, both in lower and in upper jaw. None of the temporary or definite prostheses were lost over the follow-up period of 3 years. After 1 year, the mean bone loss was 1.13 mm (SD 0.94; range -0.1 to 3.8), and after 3 years, it was 1.61 mm (SD 1.40; range 0 to 5). The mean bone loss between the 1-year and 3-year follow-ups was 0.48 mm (SD 0.66; range -1.2 to 3.6). This difference was statistically significant (p < .001), indicative of ongoing bone loss. Twenty-six percent of the implants had bone loss above 1.5 mm after 1 year, but after 3 years, 30% of the implants had already lost more than 1.9 mm. CONCLUSION: The implant and prosthetic survival was 100%, and patients benefited from the All-on-4 treatment. However, unacceptable ongoing bone loss was seen in 49.2% of the patients; this may be a warning sign for future problems and needs clinical attention. Overloading and surgery-related aspects need to be investigated as potential explanations.

Peri-implant outcome of immediately loaded implants with a full-arch implant fixed denture: a 5-year prospective case series.

This prospective study evaluated clinical results of immediately loaded Biomet 3i implants with different surface topographies. Thirty-three periodontally compromised patients received 163 implants (130 in the maxilla and 33 in the mandible; 132 NanoTite and 31 Osseotite). After a mean loading period of 57 months, the survival rate was 96.3%. Mean crestal bone loss was 1.6 mm. No difference in bone loss was detected between the two surfaces. Only 6% of the implants had peri-implantitis based on total bone loss above 2 mm from the day of surgery in conjunction with probing depths of > 4 mm.

The histological evaluation of osseointegration of surface enhanced microimplants immediately loaded in conjunction with sinuslifting in humans.

OBJECTIVE: The aim was to investigate histomorphometrically whether or not implant surface nanotopography improves the bone response under immediate loading simultaneous to sinus grafting. MATERIALS AND METHODS: Dual acid-etched titanium microimplants with/without crystalline surface deposition of calcium phosphate particles were placed in bilateral sinuslift areas grafted with a mixture of iliac crest bone and BioOss. Surface topography of microimplants was characterized using interferometry. Loaded microimplants (MsL) were immobilized in a provisional bridge supported by four normal size implants. Some patients had unloaded microimplants as controls (MsU). Biopsies were trephined after 2 or 4 months and histomorphometric analysis of bone area (BA) and bone-to-implant contact (BC) was performed. Nonparametric methods for dependent data were used to compare effect of surface modification, and healing time (2 vs. 4 months). RESULTS: A total of 53 biopsies were available from 13 patients. A total of 4/28 and 1/11 MsL failed after resp. 2 and 4 months vs. 0/6 and 1/5 MsU. Many loaded biopsies were damaged at the apical portion and showed no bone adhesion. MsL decreased in BA from coronal to apical from 2 to 4 months; Coronal > Middle (P = 0.047), Coronal > Apical (P < 0.001) and Middle > Apical (P < 0.001). This gradual decrease was not observed for BC; Coronal < Middle and Middle > Apical (P < 0.001). Only the middle part showed significant bone contact after 2 months. For MsL there was no statistically significant difference between surface or time indicating that improvement of osseointegration over time due to maturation of the graft was poor. The MsU did not show any difference between Osseotite and Nanotite for BIC and BA (P > 0.05) but doubled both their BA and BIC (P < 0.05) between 2 and 4 months. CONCLUSIONS: Osseointegration in sinus-grafted bone mixed with BioOss was poor irrespective of healing time or nanotopographical surface modification. The apex of MsL showed minimal bone contact suggesting that the graft does not add to the loading capacity. Surface enhancement was not beneficial despite the enlarged surface area. Overloading, most critical coronally of an implant, increases risks for implant failure and jeopardizes bone healing especially under immediate loading conditions with high load.

A retrospective analysis of early and immediately loaded osseotite implants in cross-arch rehabilitations in edentulous maxillas and mandibles up to 7 years.

BACKGROUND: Immediate loading of full-arch restorations yields good results in selected cases, but long-term follow-up and the outcome in compromised bone are scarcely evaluated. PURPOSE: To evaluate immediately loaded Osseotite implants (Biomet 3i, Palm Beach, FL, USA) installed in healed or grafted bone, with regard to implant survival and peri-implant bone loss up to 7 years in function. MATERIALS AND METHODS: Information was retrospectively retrieved from 83 patients' records with 749 Osseotite implants supporting immediately loaded semipermanent full-arch acrylic restorations. Five hundred sixty-eight (75.8%) implants were placed in healed bone and 181 (24.2%) in augmented bone, regenerated with sinus lifting and/or onlay/inlay grafts with/without biomaterials and membranes. Implant survival and success based on radiological peri-implant bone loss were registered. Wilcoxon rank sum tests evaluated peri-implant bone loss in compromised versus healed bone or between jaws or time intervals with p<.05 as statistically significant. RESULTS: Sixteen of 749 implants failed (2.1%), 11/343 in maxilla (3.2%) and 5/406 (1.2%) in mandible. After 7 years, the cumulative failure rate was 9%. Mean peri-implant bone loss increased to 1.2 mm (SD 1.0) during the first 2 years but remained unchanged thereafter. Around implants in grafted bone, on average, 0.3 mm more bone loss was found. CONCLUSION: The Osseotite implants offer a predictable long-term outcome in terms of implant survival and stable peri-implant bone under immediate loading even in grafted bone. However, the high incidence of technical repair because of fractures of the semipermanent provisionals requires attention because it may be negative from a cost-benefit perspective. Implants in grafted bone show a tendency to a more pronounced initial bone remodeling without clinical consequence in the long term.

Factors associated with failure of surface-modified implants up to four years of function.

OBJECTIVES: The relative impact of innovative treatment concepts on the failure of surface-modified implants is not well understood. This retrospective study aimed to explore this using data obtained in a university postgraduate training center. MATERIAL AND METHODS: Patients treated with implants for a variety of indications over a 3-year period were included. All implants had been at least 1 year in function. Clinical records were evaluated for implant failure and in reference to implant length/diameter/location, time from tooth loss to implant placement, bone condition (native/grafted), surgical protocol (two-/one-stage), loading protocol (delayed/early/immediate), type of prosthesis (removable/fixed), surgeon's experience level (resident/trainee) and specialty (periodontist/oral surgeon). The impact of each covariate on failure was tested using the Fisher's exact test. Kaplan-Meier survival functions were constructed and Mantel-Cox log-rank tests were used to compare survival functions. To correct for possible interaction, Cox proportional Hazards regression was adopted. RESULTS: Forty-one of 1,180 (3.5%) implants were lost in 34/461 (7.4%) patients (245 ♀, 216 ♂; mean age 51, range 18-90). Factors showing significant impact on failure on the basis of univariate analyses were implant location (p = .015), surgical protocol (p = .002), loading protocol (p = .002), surgeon's experience level (p = .035) and specialty (p = .001). When controlling for other covariates, only the loading protocol had a significant influence (p = .049) with early loading more prone to failure (p = .014) when compared with delayed loading. Immediate loading and delayed loading showed comparable implant survival (p = .311). CONCLUSIONS: Implant therapy may be highly successful in a training center where inexperienced clinicians are strictly monitored and personally guided. Implant specific variables do not affect implant survival but early loading is a risk indicator for implant failure, whereas immediate loading is not.

Healing of extraction sockets filled with BoneCeramic® prior to implant placement: preliminary histological findings.

BACKGROUND: Various grafting materials have been designed to minimize edentulous ridge volume loss following tooth extraction by encouraging new bone formation in healing sockets. BoneCeramic® is a composite of hydroxyapatite and bèta-tricalcium phosphate with pores of 100-500 microns. PURPOSES: The aim of this study was to evaluate bone regeneration in healing sockets substituted with BoneCeramic® prior to implant procedures. MATERIALS AND METHODS: Fifteen extraction sockets were substituted with BoneCeramic® and 14 sockets were left to heal naturally in 10 patients (mean age 59.6 years). Biopsies were collected only from the implant recipient sites during surgery after healing periods ranging from 6-74 weeks (mean 22). In total, 24 biopsies were available; 10 from substituted and 14 from naturally healed sites. In one site, the implant was not placed intentionally and, in four substituted sites, implant placement had to be postponed due to inappropriate healing, hence from five sites biopsies were not available. Histological sections were examined by transmitted light microscope. RESULTS: At the time of implant surgery, bone at substituted sites was softer than in controls, compromising initial implant stability. New bone formation at substituted sites was consistently poorer than in controls, presenting predominantly loose connective tissue and less woven bone. CONCLUSION: The use of BoneCeramic® as a grafting material in fresh extraction sockets appears to interfere with normal healing processes of the alveolar bone. On the basis of the present preliminary findings, its indication as a material for bone augmentation, when implant placement is considered within 6-38 weeks after extraction, should be revised.

[Giant cell peripheral granuloma surrounding a dental implant: case report]. / Granulome périphérique à cellules géantes au niveau d'un implant dentaire: rapport de cas.

BACKGROUND: The rising number of dental implants placed in the treatment of partial or full edentulism confronts the clinician with more implant-related pathology. The presence of a transmucosal component resembles the natural tooth and makes it likewise prone to oral plaque adhesion and plaque-related diseases. However, non-plaque-related diseases can also occur around implants. CASE: This clinical case describes the historical background, the diagnosis, treatment and follow-up of a 33-year-old female patient presenting with a peripheral giant cell granuloma surrounding a maxillary implant. Diagnosis was established by histopathologic analysis. The treatment consisted of complete excision and bone curettage, strict plaque-control and intensive aftercare. Eight months later, no recurrence had been observed. Nevertheless, the soft tissues did not return exactly to their original situation. CONCLUSIONS: Early diagnosis by means of a biopsy is crucial when an epulis is detected. This results in both a less invasive excision and a more favorable aesthetic outcome.

Patient-centered outcome of immediately loaded implants in the rehabilitation of fully edentulous jaws.

INTRODUCTION: Edentulism often involves functional, esthetic, phonetic and psychological problems. OBJECTIVES: To evaluate patient-centered outcomes of full-arch screw-retained rehabilitation on immediately loaded implants. MATERIAL AND METHODS: Fifty patients treated with Astra Tech(TM) implants answered self-administered questionnaires on a visual analogue scale (VAS) 100 mm scale or with multiple-choice or open questions: at baseline, 1 week, 3 or 6 months and 1 year. Changes of VAS in time were analyzed using mixed models for repeated measures, adjusting for gender, age and jaw; comparison of cross-sectional parameters between jaws was performed with the Mann-Whitney U- or chi(2)-test, all at the 0.05 significance level. RESULTS: The median calculated general satisfaction score increased from 40.25 (mean=40.9; SD=23.82; range=0-95) at baseline to 98.25 (mean=95.3; SD=6.68; range=74-100) after 1 year. Overall comfort, eating comfort, speaking comfort and perceived esthetics improved significantly within 1 week after surgery and immediate provisionalization. This did not change significantly until the final bridge was installed after 3 months (mandible) or 6 months (maxilla), when a further significant improvement was demonstrated. The most common postoperative complication was swelling, especially in the maxilla. The importance of one-stage surgery and immediate loading was rated very high by patients before treatment, especially in the mandible. The main reason for choosing fixed prosthetics was eating comfort. Phonetics and esthetics were more important in the maxilla than in the mandible. CONCLUSION: Immediate full-arch rehabilitation yeilds an instant significant improvement in general patient satisfaction and self-perceived factors related to comfort, function and esthetics. Eating comfort is the main concern for the patient and shows the highest improvement. Postoperative complications are limited and patients considered immediate loading important.

A literature review on biomaterials in sinus augmentation procedures.

BACKGROUND: Sinus augmentation is a common procedure to increase bone volume and allow for proper implant placement in the atrophic posterior maxilla. Although the patient's own bone is considered the best grafting material, various synthetic or bovine-derived alternatives are used to simplify the grafting procedure. PURPOSE: The overall objective of this review was to assess the efficacy of different graft materials used in sinus augmentation procedures as demonstrated in animal studies. MATERIALS AND METHODS: A specific and sensitive database was initially created via PUBMED, focusing on studies published in English peer-reviewed journals between 1995 and 2004 and kept updated until 2006. RESULTS: Twenty-six articles were available for comparison and discussion; none concerned the use of alloplastic materials; 24 were comparative histomorphometric; and two were biomechanical studies. Because of a great variability in study designs, different implant types, great range in follow-up, and lack of specific integration or loading period, a comparison of the studies and the biomaterials used was difficult. CONCLUSIONS: In general, autogenous bone is the most predictable material of choice for augmentation procedures, despite a 40% resorption, because it is highly osteoconductive and less dependent on sinus floor endosteal bone migration. The addition of bovine bone mineral to autogenous bone can be beneficial for graft success because it acts as a slowly resorbing space maintainer. Porous hydroxyapatite is suitable when mixed with autogenous bone because it enhances bone formation and bone-to-implant contact in augmented sinuses. Histological evaluation showed that demineralized freeze-dried bone is inferior to other materials. Within the limitation of the animal studies examined in this review and only based on histological examination, the initial osseointegration of implants seems independent of the biomaterial used in grafting procedures.

Surgical root restoration after external inflammatory root resorption: A case report.

External inflammatory root resorption after a jaw fracture is rare. This report describes a case of extensive external root resorption in the middle third of the root of a mandibular right canine after a mandibular fracture involving the tooth socket. Because of delayed treatment and damage to the root caused by a surgical screw, root canal treatment was performed followed by surgical intervention. The resorptive defect was debrided and part of the root was rebuilt with conventionally setting restorative glass ionomer cement. Postoperative follow-up revealed complete healing.