Surgical guides for guided bone augmentation: An in vitro study.

AIM: To validate in vitro the accuracy of a novel method for bone augmentation of horizontal alveolar bone defects with the help of a surgical guide. MATERIAL AND METHODS: Six cone-beam computed tomography scans of patients requiring horizontal bone augmentation were segmented and 3D printed. Two surgeons performed the bone augmentation surgery twice for each case on 3D-printed models, using either a conventional or guided protocol. Each surgeon virtually planned the desired graft shape beforehand. The resulting grafts were compared linearly and volumetrically to the plan; graft density and surgical time were also analyzed. RESULTS: There was significantly less graft volume outside the planned volume with the guided protocol (36.8% ± 14.1 vs. 19.6% ± 12.3, p < .01). The use of a guide increased graft accuracy at several measurement points, resulting in less overfill when using the guided protocol (1.7 ± 1.7 mm at the most coronal point, 0.2 mm ± 1.4 at 25%, 0.0 mm ± 0.9 at 50%, 0.1 mm ± 1.1 at 75%, and 0.4 mm ± 1.4 apically). Graft thickness was increased 1 mm coronally from the planned graft (2.8 mm ± 2.3 vs. 1.8 mm ± 2.2, p = .04). Surgical time increased significantly when using a guide (a difference of 2 m 26 s). CONCLUSION: The technique, tested here in vitro, allows surgeons to improve the accuracy of the resulting graft shape, to better compact material in the coronal portion of the graft, and to reduce the amount of graft material placed outside the planned volume.

Stability evaluation of implants placed in the atrophic maxilla using osteotome sinus floor elevation with and without bone grafting: A 5-year prospective study.

PURPOSE: Osteotome sinus floor elevation (OSFE) is a technique aimed at simplifying implant placement in the posterior atrophic maxilla. The necessity of bone grafting under the elevated sinus membrane has been widely debated. The aim was to compare the evolution over 5 years of implant stability in sites grafted or left ungrafted. MATERIALS AND METHODS: A total of 12 patients (9 female and 3 male) presenting ≤ 4 mm initial bone height (IBH) in the posterior maxillary sites were recruited. Implants (n = 37) were placed using OSFE. According to the randomisation, the sinuses received either bone graft (n = 20, control group) or no graft (n = 17, test group). Patients received both these treatments when both sinuses fulfilled the inclusion criteria. Control assessments were performed 1 week, 10 weeks, 12 weeks, and then 1 year, 3 years and 5 years after the implant placement. Periapical radiographs were taken and the implant stability quotient (ISQ) was measured at different time points. RESULTS: At implant surgery, the mean ISQ was 58.9 ± 11.2 for the test group and 53.8 ± 10.2 for the control group; it plummeted 10 weeks after the implant placement and rose thereafter. Five years after the implant placement, the mean ISQ reached 80.8 ± 4.2 for the control group, and 79.7 ± 4.3 for the test group. The difference between the groups was not significant. The IBH significantly affected implant stability at implant insertion and 5 years after the implant insertion, but not at the other time points. CONCLUSIONS: The implants performed using OSFE in ungrafted sites were as stable as the implants placed in grafted sites.

Relationship of implant stability and bone density derived from computerized tomography images.

BACKGROUND AND PURPOSE: Implant stability is one of the most important factors influencing osseointegration. Using stereolithographical guides for maximizing precision, this study aimed at investigating the relationship between implant stability and bone density derived from computerized tomography analysis. MATERIALS AND METHODS: One hundred ninety-five implants were placed in 48 patients using digitally designed stereolithographical surgical guides. Ninety-five implants were placed using a mucosa supported guide and 100 implants were placed using a bone supported guide. Implant stability was measured by means of resonance frequency analysis (RFA) and damping capacity assessment (Periotest, PTV). Bone density (Hounsfield units) was measured at different regions of interest (ROI) and cortex thickness was measured around each implant. RESULTS: Implant stability correlated significantly with the different ROI. The best correlation for RFA was obtained for the spongious bone ROI (r = .64) and PTV best correlated with the coronal cortex density (r = -.41). Shorter implants (9 mm) had a significantly lower primary stability than longer implants (11, 13, 15 mm). Primary stability was also significantly higher in 4 mm diameter implants than in 3.5 mm diameter implants. A formula for the prediction of primary stability based on the different variables investigated was developed. CONCLUSIONS: Bone density and cortex thickness have a significant influence on implant primary stability. Longer and wider implants reached higher primary stability than shorter and narrower implants. These correlations lose their significance after osseointegration has taken place. Implant stability can be predicted based on an preoperative analysis of bone characteristics.

The fate of buccal bone around dental implants. A 12-month postloading follow-up study.

INTRODUCTION AND AIM: Buccal bone thickness is considered to be an important factor during implant surgery. Its resorption might have an effect on the soft tissue stability and eventually on implant survival. This study aimed to investigate the resorption of the buccal bone over the first 12 months after implant loading. MATERIALS AND METHODS: Twenty-four subjects (47 implants) were included. The buccal bone thickness was measured during implant surgery at several distances from the implant shoulder using a specifically designed device which allows buccal bone thickness measurements without the elevation of a muco-periostal flap. These measurements were repeated after 12 months of loading. Sixteen implants were placed flapless and 31 with the elevation of a flap. Of the latter, 19 were placed following a one-stage protocol and 12 following a two-stage protocol. RESULTS: The mean reduction in buccal bone thickness, when all groups pooled, was 0.26, 0.36, 0.35 and 0.27 mm at the shoulder and 2, 4 and 6 mm apically. Implants with initial bone thickness <1mm (thin buccal plate) did not lose significantly more bone than those with an initial thickness ≥1mm (thick bone plate) except in the 'open-flap, one-stage' group (P = 0.009). A flapless procedure leads to less bone resorption compared to an open-flap procedure (P = 0.03). However, the number of surgeries (one stage vs. two stages) did not influence the rate of bone resorption (P = 0.23). CONCLUSION: Within the limitations of this study, one might question the necessity of having a thick bone plate at the vestibular site of the implant.

Influence of Skeletal and Local Bone Density on Dental Implant Stability in Patients with Osteoporosis.

BACKGROUND AND PURPOSE: Osteoporosis is a major skeletal disease affecting millions of people worldwide. Recent studies claim that patients with osteoporosis do not have a higher risk of early implant failure compared to non-osteoporotic patients. The aim of this study was to assess the effect of skeletal osteoporosis and local bone density on initial dental implant stability. MATERIALS AND METHODS: Seventy-three patients were recruited and were assigned (based on a Dual-energy X-ray Absorptiometry scan) to either the osteoporosis (Opr), osteopenia (Opn), or control (C) group. Forty nine of the 73 patients received dental implants and had implant stability measured by means of resonance frequency analysis (RFA) at implant placement and at prosthetic abutment placement. On the computerized tomography scans, the cortical thickness and the bone density (Hounsfield Units) at the sites of implant placement were measured. RESULTS: At implant placement, primary stability was on average lower in group Opr (63.3 ± 10.3 ISQ) than in group Opn (65.3 ± 7.5 implant stability qutient (ISQ)), and group C (66.7 ± 8.7 ISQ). At abutment placement, a similar trend was observed: group Opr (66.4 ± 9.5 ISQ) scored lower than group Opn (70.7 ± 7.8 ISQ), while the highest average was for group C (72.2 ± 7.2 ISQ). The difference between groups Opr and C was significant. Implant length and diameter did not have a significant effect on implant stability as measured with RFA. A significant correlation was found between local bone density and implant stability for all regions of interest. CONCLUSIONS: Implant stability seems to be influenced by both local and skeletal bone densities. The lower stability scores in patient with skeletal osteoporosis reinforce the recommendations that safe protocols and longer healing times could be recommended when treating those patients with dental implants.

Prediction of implant loss and marginal bone loss by analysis of dental panoramic radiographs.

PURPOSE: One of the major factors governing implant success is the quantity and density of the host bone. The aim of this work was to determine whether mandibular bone texture and cortical width measurements on plain radiographs could be associated with implant failure and/or marginal bone loss. MATERIALS AND METHODS: A statistical model was built to predict implant failure; it incorporated several radiographic features of cortical and cancellous bone texture, cortical width, and patient smoking habits. Cortical width measurements and texture measurements of cortical and cancellous bone were made on the panoramic radiographs of 460 subjects. These were used to predict implant failure and marginal bone loss after 5 years. Receiver operating characteristic (ROC) curve analysis and area under the curve (AUC) were used to determine the diagnostic accuracy of the variables in predicting implant failure and marginal bone loss. Additionally, for 91 of 460 subjects with periapical radiographs, marginal bone levels around implants were measured over a 5-year period. RESULTS: Of the 460 patients assessed for implant failure, 29 had failed implants (93.7% success rate). The ROC curve built from this model had a sensitivity of 62.1% and specificity of 67.5%. The AUC from the model was 0.690 (95% confidence interval [CI] 0.597 to 0.783). A model was also built to predict marginal bone loss. The ROC curve had 78.6% sensitivity and 74.6% specificity (AUC = 0.880, 95% CI = 0.810 to 0.953). Mandibular cortical width was not a significant predictor of either implant failure or bone loss. CONCLUSION: In a retrospective analysis 5 years after implant placement, features of cancellous and cortical bone of the mandible were significant in predicting implant failure and marginal bone loss in a sample of 460 patients.

Relation between Spongy Bone Density in the Maxilla and Skeletal Bone Density.

BACKGROUND AND PURPOSE: Osteoporosis is a disease affecting more than 300 million people worldwide and is responsible for numerous medical complications. This study aimed to investigate the relation between skeletal and maxillary bone density. MATERIALS AND METHODS: Seventy-three patients were recruited and divided between group A (osteoporosis), group B (healthy, control), and group C (osteopenia) on the basis of a dual-energy x-ray absorptiomery (DXA) scan. These patients also received a CT scan on which bone density measurements were performed at five sites: maxilla midline, retromolar tuberosities, incisor, premolars, and molar regions. RESULTS: The bone density was lower in osteoporotic patients compared with the control patients. The bone mineral density (BMD) of the tuberosities showed the strongest correlations with the BMD of the hip and the spine (respectively, r = 0.50 and r = 0.61). The midline region showed moderate correlations with the hip (r = 0.47) and the spine (r = 0.46). For potential implant sites, the correlations with the BMD of the hip and spine were, however, small to insignificant. Based on measurements of bone density of the maxilla, it was possible to predict if the patient was osteoporotic or not with a sensitivity of 65% and a specificity of 83%. CONCLUSIONS: The maxillary bone density of subjects with osteoporosis is significantly lower than that of healthy patients. Moreover, there is a direct correlation between the density of the skeleton and the density of some sites of the maxilla. Using measurements of maxillary bone density in order to predict skeletal bone density might be a useful tool for the screening of osteoporosis.

Critical buccal bone dimensions along implants.

The buccal bone plate is a component of the alveolar process tightly related to the tooth it supports. A plethora of physiological and pathological events can induce its remodeling. Understanding this remodeling process and its extent is of major importance for the practitioner as it can affect the functional and esthetic outcome of implant surgery at the involved sites. Bone remodeling and resorption of the buccal bone plate are inevitable after tooth loss or extraction. To limit resorption, several ridge-preservation techniques of varying efficacy have been described. Bone resorption is equally found to occur upon implant placement and is thought to be a result of the surgical trauma inflicted as well as an adaptation process of the tissues to the new foreign body. Because of the implications of bone resorption on the soft-tissue levels and the general esthetic outcome, it is of primary importance for the practitioner to be able to evaluate the hard tissues and the inherent resorption risks in an effort to optimize the treatment strategies. Based on limited short-term data, the present general opinion advises the need for a 2-mm-thick buccal bone plate in order to avoid vertical bone resorption.

Periodontal regeneration with enamel matrix derivative in reconstructive periodontal therapy: a systematic review.

BACKGROUND: Enamel matrix derivative (EMD) is commonly used in periodontal therapy. The aim of this systematic review is to give an updated answer to the question of whether the additional use of EMD in periodontal therapy is more effective compared with a control or other regenerative procedures. METHODS: A literature search in MEDLINE (PubMed) for the use of EMD in periodontal treatment was performed up to May 2010. The use of EMD in treatment of intrabony defects, furcations, and recessions was evaluated. Only randomized controlled trials with ≥1 year of follow-up were included. The primary outcome variable for intrabony defects was the change in clinical attachment level (CAL), for furcations the change in horizontal furcation depth, and for recession complete root coverage. RESULTS: After screening, 27 studies (20 for intrabony defects, one for furcation, and six for recession) were eligible for the review. A meta-analysis was performed for intrabony defects and recession. The treatment of intrabony defects with EMD showed a significant additional gain in CAL of 1.30 mm compared with open-flap debridement, EDTA, or placebo, but no significant difference compared with resorbable membranes was shown. The use of EMD in combination with a coronally advanced flap compared with a coronally advanced flap alone showed significantly more complete root coverage (odds ratio of 3.5), but compared with a connective tissue graft, the result was not significantly different. The use of EMD in furcations (2.6 ± 1.8 mm) gave significantly more improvement in horizontal defect depth compared with resorbable membranes (1.9 ± 1.4 mm) as shown in one study. CONCLUSIONS: In the treatment of intrabony defects, the use of EMD is superior to control treatments but as effective as resorbable membranes. The additional use of EMD with a coronally advanced flap for recession coverage will give superior results compared with a control but is as effective as a connective tissue graft. The use of EMD in furcations will give more reduction in horizontal furcation defect depth compared with resorbable membranes.

Relationship between cortical bone thickness or computerized tomography-derived bone density values and implant stability.

AIMS: To explore the relationship between primary implant stability and different parameters related to implant or bone properties. MATERIALS AND METHODS: Twenty-four patients received a total of 136 Straumann SLActive implants. Resonance frequency analysis (RFA) was performed at implant placement, and RFA and Periotest (PTV) were scored at loading. Bone density [Hounsfield (HU) scores] and coronal cortical thickness at osteotomy sites were measured from pre-operative computerized tomography scans. RESULTS: Implant length, diameter or the presence of bony dehiscence did not have a significant effect on the mean RFA scores at implant insertion. Significant linear relations were found between RFA or PTV scores and HU values (P<0.05), or cortical bone thickness (P<0.05), both at insertion as well as at loading. CONCLUSION: RFA and PTV scores can be predicted based on implant and especially bone related factors.

Influence of bony defects on implant stability.

INTRODUCTION: The purpose of this study was to analyze the evolution of implant mechanical stability in different types/sizes of bony defects using both Periotest and Osstell devices as "objective tools." MATERIALS AND METHODS: Thirty-two implants were randomly allocated to one of the four types of bone defects: marginal bone loss, peri-apical bone defect, constant width dehiscence and constant length dehiscences. Periotest/Osstell measurements were completed before and during staged bone removal (to enlarge defect size). RESULTS: Significant differences (P<0.05) with initial values were found after a 2 mm marginal bone removal (Osstell/Periotest); for a peri-apical bone lesion, after removal of 5 mm (Osstell) or 8 mm (Periotest); for a 6-mm-long dehiscence, after removal up to 180 degrees of the implant perimeter (Osstell/Periotest); for a 3-mm-wide dehiscence, after removal of 10 mm (Osstell) or 6 mm (Periotest). CONCLUSION: Periotest and Osstell are in general not very sensitive in the identification of peri-implant bone destruction, except for marginal bone loss.

Critical horizontal dimensions of interproximal and buccal bone around implants for optimal aesthetic outcomes: a systematic review.

OBJECTIVE: This systematic review was initiated to explore the critical horizontal interproximal and buccal bone dimensions around implants for an optimal aesthetic outcome. MATERIALS AND METHODS: Pubmed, the Cochrane and the ISI web of Science databases were searched to identify eligible human studies that reflect on the aesthetic outcome of implants in relation to the thickness of the buccal bone after osteotomy preparation, and in relation to the tooth-to-implant or interimplant distance. Vertical bone dimensions were not considered. RESULTS AND DISCUSSION: Articles relating horizontal buccal bone dimensions to aesthetic outcome could not be retrieved. The relation between horizontal buccal bone dimensions and vertical bone resorption could also not be confirmed. In relation to horizontal interproximal bone dimensions, some uniformity was detected among the limited number of articles. CONCLUSIONS: Interproximally, a 3 mm interelement distance seems to result more frequently in an adequate papillary fill. In the bucco-oral direction, there is insufficient evidence to set a threshold for minimal buccal bone thickness to ensure an optimal aesthetic outcome. Many additional factors appear to be of importance and interact with each other.