Simultaneous or staged installation with guided bone augmentation of transmucosal titanium implants

Vertical ridge augmentation using guided bone regeneration procedure and dental pulp derived mesenchymal stem cells with simultaneous dental implant placement: A histologic study in a sheep model

OBJECTIVES

To determine the effects of bone graft and dental pulp derived mesenchymal stem cells (DPMSCs) implantation with simultaneous dental implant placement on osteointegration, newly formed bone and vertical bone height histologically and histomorphometrically in a sheep model.

MATERIAL AND METHODS

A total of 48 implants were divided into three groups. In Group I (n = 16), no material was placed around the implants. In Group II (n = 16), particulate deproteinized bovine bone graft (DBBG) was placed around the implant and in Group III (n = 16), 2 × 106 DPMSCs were placed around the implant with DBBG. All implants were covered with a 20 × 30 mm collagen membrane and the edges of the membrane were fixed with mini screws. The animals were sacrificed 3 and 6 weeks after surgery. Histologic and histomorphometric assessments were performed.

RESULTS

The area of newly formed bone in Groups I, II, and III were calculated as percentage 2.15 ± 0.22, 11.88 ± 0.77, and 14.50 ± 0.67 respectively after 3 weeks and 3.33 ± 0.37, 18.45 ± 0.33, and 29 ± 1.07 after 6 weeks, respectively (P < 0.05). Three weeks after dental implant placement, the vertical bone length was 0.17 ± 0.02 mm in Group I, 0.89 ± 0.068 mm in Group II and 0.96 ± 0.05 mm in Group III. After 6 weeks, these values were 0.28 ± 0.03 mm, 1.34 ± 0.08 mm, and 1.49 ± 0.08 mm, respectively. There was no significant difference between Groups II and III at 3 and 6 weeks in terms of vertical bone length.

CONCLUSION

Bone graft and DPMSCs application with dental implant have beneficial effects on newly formed bone and vertical bone height in this experimental sheep model.

The effect of membrane exposure on lateral ridge augmentation: a case-controlled study

BACKGROUND

The effect of membrane exposure on guided bone regeneration (GBR) for lateral ridge augmentation has been poorly addressed. This case-controlled study aimed to investigate potential effect of membrane exposure lateral ridge augmentation and subsequent implant placement.

METHODS

A total of 14 patients that did receive lateral ridge augmentation procedure using allogeneic cancellous graft particulate in combination with an alloplastic bioresorbable matrix barrier were retrospectively selected for this study. Bone width was measured at the crest with a digital caliper before bone augmentation and at the reopening for implant placement 4 months later for all patients. Cases where primary flap closure was achieved and the barrier did not expose throughout the time until implant placement were assigned to the control group (n = 7). Cases where primary closure could not be achieved or a barrier exposure happened within the first week following the initial surgery were assigned to the test group.

RESULTS

The measured alveolar ridge width before surgery as well as after GBR procedure were not statistically significant different between the two groups (p > 0.05). Both groups showed a significant (p < 0.05) increase in their mean alveolar ridge width 4 months after later augmentation procedure, from 3.4 ± 1.2 to 6.0 ± 1.1 mm in the control group and from 3.6 ± 1.0 to 5.0 ± 1.4 mm in the test group. However, the mean alveolar ridge gain was significantly greater in the control group than in the test group (p < 0.05). Consequently, the reduction of the augmented alveolar ridge was significantly higher in the test group averaging to 4.7 mm than for the control group showing a loss of 3.1 mm after 4 months, respectively. However, in all 14 cases, successful implant placement was achieved after 4 months.

CONCLUSIONS

Within the limit of this study, it can be concluded that early exposure of a bioresorbable matrix barrier during lateral ridge augmentation may compromise the results of the GBR procedure but may still result in a favorable alveolar ridge width gain that allows for the placement of dental implants.

Horizontal bone augmentation in full-arch maxillary implant-supported restorations: a preliminary clinical report

PURPOSE

The purpose of this study was to describe a technique for horizontal maxillary bone grafting in combination with implant placement for full arch.

MATERIALS AND METHODS

Patients requiring complete rehabilitation of the edentulous maxillae were included. Two axial mesial implants and 2 tilted distal ones were placed approximately 2 mm buccally about the centre of the bone crest. A graft made of a mixture of deproteinized bovine bone and platelet-rich plasma was placed buccally covering bony dehiscence. Horizontal bone gain and differences in bone volume were evaluated 6 months after surgical intervention, at the time of prosthetic loading, through comparison of standardized cone beam computed tomographic scans.

RESULTS

A total of 10 patients were consecutively treated after the proposed protocol. After 6 months, the mean horizontal bone gain was 1.87 ± 0.54 mm for the left side and 1.79 ± 0.78 mm for the right side without any significant difference between them. The bone volume increased by 610.5 ± 27.57 mm after 6 months.

CONCLUSIONS

It can be postulated that the proposed protocol may provide a significant horizontal bone gain for minimizing the anterior cantilever in full-arch prosthesis.

A Retrospective Evaluation of 192 Implants Placed in Augmented Bone: Long-Term Follow-Up Study

The purpose of the present study was to assess the cumulative survival rate (CSR) of 192 implants placed in association with guided bone regeneration (GBR) procedures to evaluate the long-term predictability of this technique. Moreover, the Kaplan Meier survival analysis was applied to the data in order to evaluate predictors of implant failures, including the source of the graft, the type of membrane, and the timing of implant placement. The CSR of the sample was 95.6% over a mean follow-up period of 78 months (range, 1-175 months). Considering the source of graft, a 95.0%, 93.3%, and 97.7% CSR was obtained for demineralized bovine bone mineral (DBBM), autologous, and 1:1 ratio mixture of autologous and DBBM grafts,, respectively. The CSR referred to bioabsorbable membranes was 96.5%, whereas 94.6% was the CSR reported for nonresorbable membranes. The CSR of simultaneous surgeries was 96.8%, whereas staged surgeries showed a CSR of 94.5%. According to the data, implants placed in conjunction with GBR procedures presented a satisfying survival rate even in the long term. All the procedures performed with different bone grafts and type of membranes guaranteed optimal results both in one- and two-stage approaches. No statistically significant differences could be detected among the groups; indeed, the use of DBBM associated with resorbable membranes may be suggested to reduce patients' morbidity and treatment time. Therefore, the dental implants placed in association with bone regenerative procedures presented safe and predictable long-term clinical results.

A clinical prospective study on alveolar bone augmentation and dental implant success in patients with type 2 diabetes

OBJECTIVES

The objective of this prospective, controlled clinical study was to determine the outcomes of dental implant therapy with staged guided bone regeneration procedures in patients with type 2 diabetes.

PATIENTS AND METHODS

Twenty-four patients were included in the study. Half of the patients were diagnosed with type 2 diabetes mellitus (group 1) while the other half (group 2) of the patients consisted of patients without diabetes. The edentulous maxillary anterior/premolar regions with sufficient vertical height but inadequate horizontal width were treated with staged guided bone regeneration technique and with one or two implant-supported fixed restorations. The patients were followed up at least for 12 months. The parameters that were evaluated were radiographic evaluations on CBCT images and periapical radiographs, histomorphometric analysis, resonance frequency analysis (RFA) and wound-healing parameters. The data were analyzed statistically.

RESULTS

A total of 43 implants were placed in 24 patients (22 implants in group 1 and 21 implants in group 2). The survival rates of implants were 100% for both groups. The success rate of implants was 95% for group 1 and 100% for group 2. None of the parameters including CBCT findings, RFA values, success rates and wound-healing scores showed a significant difference between the two groups.

CONCLUSION

Staged guided bone regeneration is a feasible augmentation procedure for the treatment of horizontal bone deficiencies of the maxillary anterior/premolar regions in well-controlled type 2 diabetic patients.

Implant treatment choice after extraction of a vertically fractured tooth. A proposal for a clinical classification of bony defects based on a systematic review of literature

OBJECTIVES

The objectives of this study were to propose a classification for the bone defects resulting after extraction of a vertically fractured tooth and to review the existing literature about the treatment of such kind of defects by means of dental implants in combination with regenerative procedures.

MATERIALS AND METHODS

An electronic search was performed on biomedical databases using a combination of appropriated search terms combined through the use of Boolean operators. All articles concerning the treatment of peri-implant bone dehiscences and fenestrations through guided bone regeneration (GBR) with at least 6 months follow-up were eligible. Outcomes data extracted from the selected articles were summarized using descriptive tables. A classification of the bone defects associated with vertical root fracture (VRF) was also proposed.

RESULTS

A total of 33 articles were included in the review. Twenty-three articles (814 implants) were about bone dehiscence treatment, ten articles presented the treatment of fenestrations, and ten (429 implants) adopted vertical bone augmentation. The percentage of bone filling was variable among different procedures and defect classification. The use of resorbable membrane was associated with better outcomes than the use of non-resorbable ones.

CONCLUSIONS

Guided bone regeneration for the management of bone defects in the presence of a VRF of the extracted tooth is a viable treatment option. The assessment of bone defect geometry prior to a tooth extraction could be clinically relevant for evaluating the feasibility and the success of immediate implant placement as well as the need of GBR.

Systematic review of pre-clinical models assessing implant integration in locally compromised sites and/or systemically compromised animals

OBJECTIVE

The aim was to systematically search the dental literature for pre-clinical models assessing implant integration in locally compromised sites (part 1) and systemically compromised animals (part 2), and to evaluate the quality of reporting of included publications.

METHODS

A Medline search (1966-2011) was performed, complimented by additional hand searching. The quality of reporting of the included publications was evaluated using the 20 items of the ARRIVE (Animals in Research In Vivo Experiments) guidelines.

RESULTS

One-hundred and seventy-six (part 1; mean ARRIVE score = 15.6 ± 2.4) and 104 (part 2; 16.2 ± 1.9) studies met the inclusion criteria. The overall mean score for all included studies amounted to 15.8 ± 2.2. Housing (38.3%), allocation of animals (37.9%), numbers analysed (50%) and adverse events (51.4%) of the ARRIVE guidelines were the least reported. Statistically significant differences in mean ARRIVE scores were found depending on the publication date (p < 0.05), with the highest score of 16.7 ± 1.6 for studies published within the last 2 years.

CONCLUSIONS

A large number of studies met the inclusion criteria. The ARRIVE scores revealed heterogeneity and missing information for selected items in more than 50% of the publications. The quality of reporting shifted towards better-reported pre-clinical trials within recent years.

Timing of implant placement and augmentation with bone replacement material: clinical assessment at 8 and 16 months

PURPOSE

The purpose of this study is to evaluate implants placed at different times of bone augmentation.

MATERIALS AND METHODS

Four implants were placed in seven dogs: one at a 6-month bovine mineral grafted site (6-month Bio-Oss® grafted site [6mBio]), one at a grafted membrane-protected simultaneously augmented (Fresh Bio-Oss® grafted site [FrBio]) site, one at a clotted (nongrafted clotted membrane-protected site [Clot]) membrane-protected site, and one at a pristine (nongrafted uncovered site [Cont]) site. Implants were exposed after 6 months. The same protocol was repeated on the contralateral side, at a delay of 8 months. Peri-implant care was performed throughout the hygienic phase (2 and 10 months, respectively) every 48 to 72 hours. Probing depth and bleeding on probing were recorded. Implant stability was determined by a Periotest® (Medizintechnik Gulden, Modautal, Germany). Statistical analysis was conducted using analysis of variance with repeated measures.

RESULTS

Average probing depth at the simultaneously grafted sites was 2.21 mm and 2.03 mm at 8 and 16 months, respectively. At the 6-month grafted sites, it was 1.96 mm and 1.57 mm. At the Clot sites, it was 2.68 mm and 2.07 mm, and 2.21 mm and 1.82 mm at the Cont sites, respectively. The average bleeding on probing was 0.50 and 0.42 at the FrBio sites, and 0.35 and 0.07 at the 6mBio sites during the respective periods. At the Clot sites, it was 0.50 and 0.28, and at the Cont sites, 0.43 and 0.21, respectively. Probing depth significantly reduced over the time at 6mBio, Clot, and Cont sites (p < .03). Average implant stability score at the FrBio sites was -0.24 and -0.27, and -0.50 and -0.46 at the 6mBio sites, at 8 and 16 months, respectively. At the Clot sites, it was -0.35 and -0.46. Cont sites averaged -0.37 at both periods. Implant stability was significantly higher (p < .005) comparing 6mBio over FrBio, 6mBio over Cont, and Clot over FrBio sites.

CONCLUSIONS

Immediate and delayed augmentations are safe modes. Probing depth and bleeding indices gradually improved along time. Implant stability was higher at the delayed mode.

Implant Installation With Simultaneous Ridge Augmentation. Report of Three Cases

The anatomic limitations of the residual alveolar bone may cause problems for the insertion of dental implants because implant placement requires an adequate quantity and quality of bone. Ridge augmentation has been performed to reconstruct alveolar ridges as support for the placement of dental implants with a high success rate. However, a staged approach requires multiple surgeries and more treatment time. In this report, the patients were treated with dental implantation with simultaneous ridge augmentation in both submerged and nonsubmerged cases. The prostheses were well in function without any probing depth or gingival inflammation up to final evaluation. It may be suggested that dental implantation with simultaneous bone grafting may be an option when the graft material can be well stabilized around the implants. Further evaluations over long periods of time are needed to monitor the clinical results.

Vertical bone augmentation with simultaneous implant placement using particulate mineralized bone and mesenchymal stem cells: a preliminary study in rabbit

This study aimed to assess vertical bone augmentation with simultaneous implant placement in rabbit tibiae using particulate mineralized bone/fibrin glue/mesenchymal stem cell. Bone marrow was aspirated from tibiae of five 10-week-old New Zealand White male rabbits. Right and left tibiae of each rabbit were prepared, and a 3-mm protruding implant from tibial bone was placed in each side. Particulate allogenic bone/fibrin glue/mesenchymal stem cell combination was placed around test implants and particulate bone graft/fibrin glue around controls. Two months postoperatively, the animals were euthanized, and sections were prepared for histological analysis. The mean amount of vertical bone length was higher in the experimental group than the control group (2.09 mm vs 1.03 mm; P < .05). New supracrestal trabecular bone formation was also significantly higher in the test group (28.5 ± 4.5% vs 4.3 ± 1.8%; P < .05). Mesenchymal stem cell/particulate allograft/fibrin glue appears to be a promising combination for vertical bone augmentation around simultaneously inserted implants in rabbit tibia.

Experimental immediate loading of dental implants in conjunction with grafting procedures

The aim of this study was to evaluate immediate loading (IL) of dental implants in conjunction with grafting procedures. A total of 107 IL implants were inserted in six mini pigs. Before implant placement, crestal or apical defects were created, which were treated with bone chips, phycogene hydroxyapatite (HA), bovine HA, or bovine HA enhanced with a synthetic peptide. Crestal grafts were stabilized with titanium membranes. All bridges were in function and showed signs of chewing wear after 4-month loading. Three out of 107 implants showed no osseointegration (2.7%). Most of the crestal defects showed incomplete regeneration, due to an infection of the membranes (74.3%) The difference in height between surgical and remaining defect was calculated as defect development, which was 2.3 +/- 2.08 mm for bone chips with an area of regenerated bone of 22.8 +/- 3.34% and 0.7 +/- 2.22 mm for phycogene HA with 11.3 +/- 4.36% regenerated bone. Bovine HA showed an increase of defects 1.3 +/- 2.47 mm with only 7.9 +/- 1.7% bone regeneration. Bovine HA enhanced with a peptide showed a defect development of 1.1 +/- 1.42 mm with an area of regenerated bone of 18.2 +/- 2.38%. In conclusion, local grafting procedures did not disturb the course of osseointegration for immediate loaded implants if primary stability was reached. The regeneration of apical defects was uneventful even with immediate loading. Crestal defects required membrane fixation with a careful flap elevation to avoid membrane exposure and loss of the graft.

In vitro scanning electron microscopic comparison of inner surface of exposed and unexposed nonresorbable membranes

OBJECTIVE

The purpose of this study was to analyze the attached tissues and the membrane surface condition according to barrier membrane exposure.

STUDY DESIGN

The selected patients underwent implant surgery with guided bone regeneration, then were surgically reentered to remove the membrane when the membrane was exposed early or when the second surgery of implant was done. The membranes used in the study included titanium mesh (Jeil Medical Co., Seoul, Korea), Frios titanium shield (Dentsply Friadent, Mannheim, Germany), and TR-Goretex membrane (W. L. Gore & Associates, CA, USA). Group 1 included 9 cases that had membranes that were exposed during an early period. Each membrane was removed in 3-6 weeks. Group 2 included 8 cases that had membranes that were not exposed and each membrane was removed in 12-24 weeks during the second surgery period of implants. Removed membrane samples were observed with scanning electron microscopy.

RESULTS

The membrane surface condition and the observed tissues were significantly different between the exposed membrane group and the unexposed membrane group (P < .05). In the majority of the cases of early exposed membranes, organic film and soft tissues were observed beneath the membrane. Bony debris was observed in only 1 sample from the exposed group. In the exposed group, the degree of membrane damage was more severe than in the unexposed group. The membrane surface condition and the observed tissues had no significant difference among the 3 kinds of membranes (P > .05).

CONCLUSION

The observed tissues and the membrane surface condition were affected by the membrane exposure. If the membrane is exposed, the soft tissue and organic film interfere with direct contact to the bone, and this affects the barrier membrane surface condition and bony tissues.

What is the quality of the evidence base for pre-implant surgery of the atrophic jaw?

This review aimed to evaluate the level of evidence for bone augmentation preimplant surgery for atrophic jaws in studies which measure outcome. Medline, Embase, Cochrane library and online journal searches were performed with a defined search strategy and the abstracts screened against selection criteria. The resultant papers were sorted by study design using the Cochrane study design algorithm, analysed for clinical/statistical homogeneity and graded with the Oxford Centre of Evidence-based Medicine levels of evidence. The initial online Medline search yielded 1194 results and the Embase search yielded 490 results. Using the selection criteria, 10 studies were identified. Additionally, 5 articles were identified from bibliography and online searches, giving a total of 15 studies for grading. All 15 studies were graded as level 4 evidence. No meta-analysis of outcomes was possible with the low level of evidence and degree of heterogeneity found. The best grade of recommendation that can be made for a particular preimplant surgical bone augmentation procedure, from these level 4 studies, is Grade C. Benchmarking studies by assessing quality of evidence can be helpful to inform future study designs with respect to reporting study outcomes with a higher level of evidence.

A randomized-controlled clinical trial evaluating clinical and radiological outcomes after 3 and 5 years of dental implants placed in bone regenerated by means of GBR techniques with or without the addition of BMP-2

OBJECTIVE

The aim of this randomized-controlled clinical trial was to evaluate the long-term outcome of implants placed in bone augmented with a xenogenic bone substitute material and a collagen membrane with or without the addition of recombinant human bone morphogenetic protein-2 (rhBMP-2).

MATERIAL AND METHODS

Eleven patients received a total of 34 implants placed into sites exhibiting lateral bone defects. In a split mouth design, the defects were randomly treated with the graft material and the collagen membrane either with (test) or without (control) rhBMP-2. The patients were examined 3 and 5 years after insertion of the prosthetic restoration. Student's paired t-test was performed to detect differences between the two groups.

RESULTS

The survival rate at 3 and 5 years was 100% for both groups. The peri-implant soft tissues were stable and healthy without any difference between the two groups. The prosthetic reevaluation demonstrated four loose prosthetic screws during the first 3 years and seven ceramic chippings after 3 and 5 years. The mean distance between the first bone to implant contact to implant abutment junction at 3 years was 1.37 mm (test), 1.22 mm (control), and 1.38 mm (test), and 1.23 mm (control) at 5 years. The difference of <0.2 mm between test and control implants was not statistically significant. The mean change of the marginal bone level between baseline and 5 years ranged from -0.07 mm (mesial, test), -0.11 mm (distal, test), -0.03 mm (mesial, control), to +0.13 mm (distal, control). No statistically significant differences were observed between test and control sites.

CONCLUSION

Implants placed in bone augmented with and without rhBMP-2 revealed excellent clinical and radiological outcomes after 3 and 5 years.

A 5-year follow-up study on one-stage implants inserted concomitantly with localized alveolar ridge augmentation

The aim of this study was to evaluate the success of one-stage implants placed at the time of alveolar bone augmentation using simultaneous guided bone regeneration technique with a collagen barrier membrane in patients suffering from insufficient bone width. Seventeen patients were treated with 20 one-stage OSTEOFIX (Oulu, Finland) implants using simultaneous guided bone regeneration technique. Dehiscence defects were filled by bovine bone mineral Bio-Oss and covered with collagen membrane. Clinical and radiographic parameters of the peri-implant conditions were assessed at the moment of prosthesis placement and at 1- and 5-year follow-ups. Diagnostic dehiscence defect measurements after implant placement showed that the mean vertical defect varied from 3.8 mm to 10.0 mm. At the moment of prosthesis placement and at 1- and 5-year follow-ups all implants were stable, painless and without biological complications. Clinical and radiographic parameters of the peri-implant conditions remained stable during follow-up. The cumulative implant survival rate was 100% after the 5-year observation period and the success rate for all pooled implants was 90%. The present study showed predictable treatment outcomes recorded after 5 years of function for one-stage OSTEOFIX (Oulu, Finland) oral implants placed simultaneously with guided bone regeneration using collagen membrane and deproteinized bovine bone mineral.

Vertical alveolar ridge augmentation using autogenous bone grafts and platelet-enriched fibrin glue with simultaneous implant placement

OBJECTIVE

The aim of this study was to evaluate the combined use of autogenous bone and platelet-enriched fibrin glue as grafting material for vertical alveolar ridge augmentation with simultaneous implant placement in a canine alveolar ridge defect model.

STUDY DESIGN

In 6 mongrel dogs, bilateral vertical alveolar ridge defects were created in the mandible. After 3 months of healing, 2 dental implants were placed in each defect of the mandible, creating 6-mm supra-alveolar peri-implant defects. The 2 implants per defect were subjected to surgical treatments involving either a combination of autogenous bone grafts and platelet-enriched fibrin glue, or a conventional flap procedure only (control). After a healing period of 6 months, the dogs were humanely killed for histological and histometric analyses.

RESULTS

Implant placement alone produced limited vertical alveolar height (0.6 +/- 0.4 mm). However, alveolar augmentation including a combination of autogenous bone grafts and platelet-enriched fibrin glue with simultaneous implant placement resulted in alveolar ridge augmentation amounting to 4.2 +/- 1.0 mm, comprising 63% of the defect height. New bone-implant contact was 40.5% in the defects treated with combined autogenous bone grafts and platelet-enriched fibrin glue, and was 48.4% in the resident bone; this difference was not statistically significant.

CONCLUSION

The present study demonstrates that vertical alveolar ridge augmentation using autogenous bone grafts and platelet-enriched fibrin glue with simultaneous implant placement might effectively increase vertical alveolar ridge height and allow for an acceptable level of osseointegration.

Effect of absorbable membranes on sandwich bone augmentation

OBJECTIVES

This study was conducted to evaluate the effect of barrier membranes on sandwich bone augmentation (SBA) for the treatment of implant dehiscence defects.

MATERIAL AND METHODS

Twenty-six implant-associated buccal dehiscence defects in 22 patients were treated according to the SBA concept - mineralized human cancellous allograft (inner layer), mineralized human cortical allograft (outer layer) and coverage with barrier membrane. The defects were randomly assigned to the bovine collagen membrane (BME) group; acellular dermal matrix (ADM) group; and no membrane group. Measurements at baseline and 6 months re-entry included defect height (DH: from smooth-rough junction to the most apical part of the defect), defect width (DW: at the widest part of the defect), and horizontal defect depth (HDD: at three locations - smooth-rough junction, middle, and most apical portion of the defect). All measurements were taken from a reference stent. Statistical analyses were performed for comparison of intra- and inter-group comparisons.

RESULTS

All implants placed were successfully osseointegrated. DH at baseline for three groups were not significantly different (P=0.858). Mean % DH reductions for ADM, BME, and control groups at 6 months were 73.9+/-17.6%, 68.1+/-30.1%, and 63.6+/-23.9%, respectively, with no significant difference among the groups (P=0.686). Mean horizontal bone gain, however, was significantly greater for membrane groups (1.7 mm for ADM, 1.6 mm for BME) compared with control group (1 mm) (P=0.044). Implant exposure resulted in significant reduction in total height gain (79.1+/-14.3% vs. 57+/-23.5%, P=0.021).

CONCLUSIONS

Within the limit of this study, it is concluded that SBA technique achieved predictable clinical outcomes. The addition of absorbable membranes enhanced bone gain in thickness compared with membrane-treated sites.

Augmentation procedures for the rehabilitation of deficient edentulous ridges with oral implants

OBJECTIVES

To analyze publications related to augmentation procedures and to evaluate the success of different surgical techniques for ridge reconstruction and the survival/success rates of implants placed in the augmented areas.

MATERIAL AND METHODS

Clinical investigations published in English involving at least 5 patients and with a minimum follow-up of 6 months were included. The following procedures were considered: a) Guided bone regeneration (GBR); 2) Onlay bone grafts; 3) Inlay grafts; 4) Bone splitting for ridge expansion (RE); 5) Distraction osteogenesis (DO); and 6) Revascularized flaps. Success rates of augmentation procedures and related morbidity, as well as survival and success rates of implants placed in the augmented sites were analyzed.

RESULTS

Success rates of surgical procedures ranged from 60% to 100% for GBR, from 92% to 100% for onlay bone grafts, from 98% to 100% for ridge expansion techniques, from 96,7% to 100% for DO, and was 87.5% for revascularized flaps, whereas survival rates of implants ranged from 92% to 100% for GBR, from 60% to 100% for onlay bone grafts, from 91% to 97.3% for RE, from 90.4% to 100% for DO, and, finally, was 88.2% for revascularized flaps.

CONCLUSION

On the basis of available data it was shown that it was difficult to demonstrate that a particular surgical procedure offered better outcome as compared to another. The main limit encountered in this review has been the overall poor methodological quality of the published articles. Therefore larger well-designed long term trials are needed.

Calprotectin and cross-linked N-terminal telopeptides in peri-implant and gingival crevicular fluid

In a previous study on guided bone augmentation, a new collagen membrane was compared with an e-PTFE one on 28 partially edentulous patients who received 50 dental implants at stage 2 surgery. After implant integration and subsequent loading, we were able to recruit 22 patients with 22 implants and their contra-lateral corresponding teeth for longitudinal observation. Clinical parameters probing depth (PD), bleeding on probing (BoP), plaque index (PI), assessment of gingival crevicular fluid (GCF) and peri-implant crevicular fluid (PCF) volumes and periapical radiographs were performed at 2- and 3-year control appointments. Calprotectin (MRP 8/14) and cross-linked N-terminal telopeptide (NTx) levels in both crevicular fluids were determined by ELISA. PD was significantly reduced from years 2 to 3 appointments at implant sites as at teeth sites. At the 3-year appointment in both compartments, fluid volumes were significantly increased, which corresponded well with ascending NTx levels. The total amount of calprotectin decreased non-significantly in both GCF and PCF samples. Periapical radiographs revealed stable bone conditions around implants without significant changes from years 2 to 3 examinations. Clinical peri-implant parameters were considered as stable as the periodontal parameters of their corresponding teeth. A parallel increase in NTx levels in both GCF and PCF at 3-year appointment is not clearly understood; it may reflect an upregulation in the overall bone turnover rate.

Guided bone regeneration around non-submerged implants in narrow alveolar ridges: a prospective long-term clinical study

OBJECTIVES

This prospective clinical study investigates long-term survival and clinical parameters of non-submerged implants with large buccal dehiscences treated with a deproteinized bovine bone mineral xenograft and a non-resorbable membrane in a one-stage approach.

MATERIAL AND METHODS

Sixteen consecutive non-submerged implants (ITI Straumann) were installed in narrow alveolar ridges in 13 patients (age range: 25-61 years). All patients were non-smokers. On the buccal site the bone dehiscence ranged between 3 and 9 mm. Primary stability was achieved in all but one implant. The exposed threads were covered with a xenograft (Bio-Oss) and a non-resorbable expanded polytetrafluoroethylene membrane. The flap was sutured leaving the implant head non-submerged. The membrane was removed when (1) the membrane became exposed or (2) after a maximum of 24 weeks. All implants received singular cemented crowns. The implants were followed for a period ranging from 12 to 114 months. Whole-mouth plaque index (Pl), the % of bleeding on probing (BOP), probing depth and signs of peri-implantitis were recorded. Every year periapical radiographs were taken using a long cone technique.

RESULTS

All but one implant integrated successfully. At the time of membrane removal, all previously exposed threads were completely covered with richly vascularized tissue except for two implants where the coverage reached 63% and 87%, respectively. The whole-mouth plaque score and BOP remained low in all patients during the observation period. None of the implants had plaque and, except for one implant BOP never occurred. All implants were stable and in function. Swelling, redness or purulence was never observed. On the periapical radiographs no bone resorption was observed on the mesial and distal site except for one implant in one patient with a mesial and distal bone resorption of 2 and 3 mm. Probing depth was never higher than 3 mm except for one patient where the implant was placed deeply subgingival for esthetical reasons.

CONCLUSION

This prospective long-term study shows that with the use of non-submerged transmucosal implants, large bony dehiscences can be treated in a one-stage approach using a stiff non-resorbable membrane combined with a xenograft.