Osteotome-Induced Blood Clot and Subsequent Bone Formation with the Use of Collagen Sponge for Integration of Single Dental Implants into the Atrophied Posterior Maxilla: A Retrospective Follow-Up of 36 Implants after 5 to 13 years.

BACKGROUND: Atrophy of the posterior maxilla as a consequence of tooth loss and sinus pneumatization is a frequent condition encountered in the clinical practice. Prosthetic rehabilitation with implants in these patients often requires some kind of bone regeneration procedure to increase the bone volume. AIM: The aim of the present retrospective study is to analyze the survival and success rates of a series of implants placed in the atrophic posterior maxilla with a transcrestal osteotome procedure, without placing a bone grafting material. MATERIALS AND METHODS: From 2006 to 2014, 36 dental implants (Neoss Ltd., Harrogate, UK) were inserted in 36 patients with at least 4 mm of bone below the maxillary sinus using transcrestal osteotome sinus floor elevation and placement of collagen sponge below the sinus membrane. ISQ measurements were made after implant placement and at abutment surgery after 4 to 6 months. The vertical bone height (VBH) was evaluated in intraoral radiographs taken prior to surgery and in radiographs from annual check-up appointments 5 to 13 years after implant placement. In addition, marginal bone loss (MBL) was evaluated. RESULTS: One implant was lost after four years of prosthetic loading. The remaining 35 implants showed no complications and were loaded with single crowns after 4-6 months of healing. All 35 implants showed clinical success after 8.5 ± 2.8 years of prosthetic loading (from 5 to 13 years). The vertical bone height was 5.9 ± 1.4 mm at surgery, 9.7 ± 1.1 mm at second surgery after 4-6 months, and 8.3 ± 1.8 at the follow-up at 8.5 ± 2.8 years (from 5 to 13 years). The implant stability registered was 73.2 ± 6.2 ISQ at the surgery and 75.8 ± 3.9 at the second surgery after 4-6 months. CONCLUSIONS: The present long-term follow-up study showed that the crestal approach for sinus floor bone augmentation without additional bone grafting results in predicable bone formation and high implant survival. The osteotome technique is a valid alternative to the more invasive lateral window technique in single cases with a minimum of 4 mm of VBH below the maxillary sinus.

Factors Influencing Resonance Frequency Analysis (RFA) Measurements and 5-Year Survival of Neoss Dental Implants.

BACKGROUND: Diagnostic instruments based on resonance frequency analysis (RFA) can be utilised to assess dental implant stability during treatment and follow-up. AIM: The aim of the present study was to investigate the influence of patient- and implant-related factors on implant stability and the 5-year implant survival. In addition, the influence of stability (ISQ value) at placement and abutment connection on implant survival was evaluated. MATERIALS AND METHODS: RFA measurements from a total of 334 consecutive patients with 745 dental implants (Neoss Ltd., Harrogate, UK) were retrospectively analysed after at least 5 years in function. Statistics were used to evaluate the influence of the different variables on implant stability and implant survival. Odds ratio calculations were performed to compare the risk for implant failure using 60, 65, 70, and 75 ISQ as threshold levels at placement and loading. RESULTS: A total of 20 implant failures in 14 patients were noted during the 5 years of follow-up, giving an overall cumulative survival rate (CSR) of 97.3% at the implant level and 95.8% at the patient level. Gender, jaw, position, bone quality, and implant diameter had an influence on implant stability at placement. Jaw, bone quality, and implant diameter had an influence on stability after 3-4 months of healing. More failures were observed in full than in partial rehabilitations. Age, gender, jaw, position, bone quantity, bone quality, implant diameter, and implant length had no influence on implant survival. Implants with ISQ values below the threshold levels showed lower survival rates compared to implants with values above these levels. CONCLUSIONS: The present study showed a significantly higher risk for implant failure, showing an ISQ value below 70 and 75 at placement or after 3-4 months of healing. The results indicate that RFA measurements can be used to identify implants with increased risk for failure.

Two different implant designs and impact of related drilling protocols on primary stability in different bone densities: an in vitro comparison study.

PURPOSE: To conduct an in vitro comparison study on the primary stability of two different clinically used dental implant designs. MATERIALS AND METHODS: Eighteen pairs of osteotomies were prepared in fresh bovine bone specimens. The control implant had a subtle tapering and was placed using straight drills. The test implant had a marked tapering and was placed using tapered drills. The bone density at the experimental sites was determined in Hounsfield units (HUs) by using cone beam computed tomography and imaging software. The implants were inserted during continuous registration of insertion torque. The bone blocks were embedded in plaster for firm fixation in a rig for displacement measurements. Resonance frequency analysis (RFA) measurements were taken. A lateral force of 15 N was applied to the RFA transducer and the displacement measured in micrometers. A flex constant (µm/N) was calculated for each measurement. RESULTS: The test implants displayed statistically significantly higher primary stability than the control implants for all parameters. There was a marked difference in displacement and flex constant in low-density bone in favor of the test implant, but there was no obvious difference in higher-density bone. CONCLUSION: In this study, placement of a tapered implant design using tapered drills resulted in higher primary stability than a control implant with subtle tapering using straight drills. The results indicate that the novel implant may work particularly well in soft bone densities such as the posterior maxilla. However, clinical studies are needed to confirm this.

Clinical outcomes of an osteotome technique and simultaneous placement of Neoss implants in the posterior maxilla.

BACKGROUND: Insufficient bone volume often hamper placement of dental implants in the posterior maxilla. PURPOSE: The aim of the present clinical study was to evaluate retrospectively the clinical outcome of implant placement in the resorbed posterior maxilla using an osteotome technique without adding any grafting material. MATERIALS AND METHODS: Twenty patients with 5 to 9 mm of residual alveolar bone height in the posterior maxilla received twenty-nine implants (Neoss Ltd., Harrogate, UK) using an osteotomy technique without bone grafts. Intraoral radiographs were taken before and after implant placement, at the time of loading and after 11 to 32 months of loading (mean 16.4 months), to evaluate bone formation below the sinus membrane and marginal bone loss. Implant stability measurements (Osstell(TM) , Gothenburg, Sweden) were performed after implant installation and at abutment connection 5 months later. All implants were installed with the prosthetic platform level with the bone crest. RESULTS: No implant was lost giving a survival rate of 100% after a mean follow-up time of 16.4 months. The average vertical bone height was 7.2 ± 1.5 mm at placement and 10.0 ± 1.0 mm after 11 to 32 months. The average increase of 2.8 ± 1.1 mm was statistically significant. There was a statistically significant improvement in implant stability from 70.7 ± 9.2 implant stability quotient (ISQ) at placement to 76.7 ± 5.7 ISQ at abutment connection, 5 months later. The mean marginal bone loss amounted to 0.7 ± 0.3 mm after 11 to 32 months of loading. CONCLUSION: It is concluded that the osteotome technique evaluated resulted in predictable intrasinus bone formation, firm implant stability, and good clinical outcomes as no implants were lost and minimal marginal bone loss was observed.

A collagenated porcine bone substitute for augmentation at Neoss implant sites: a prospective 1-year multicenter case series study with histology.

BACKGROUND: The presence of localized defects and/or small amounts of bone below the maxillary sinus is a common finding, which may compromise implant placement. There is therefore a need for predictable techniques for bone augmentation in such situations. PURPOSE: The study aims to clinically and histologically evaluate a porcine bone (PB) substitute used for augmentation of the alveolar crest or the maxillary sinus floor prior to or in conjunction with implant placement. MATERIALS AND METHODS: Nineteen patients were treated with a porcine bone substitute and barrier membranes (OsteoBiol, Tecnoss Dental, Turin, Italy) for lateral bone augmentation (Group 1a) and healing of bone defects (Group 1b) or for augmentation of the maxillary sinus floor using either a replaceable (Group 2a) or an infractured bone window (Group 2b). A total of 34 implants (Neoss Ltd., Harrogate, UK) were placed in conjunction or 5 to 7 months after the procedure. Implants were followed with implant stability measurements at placement and abutment connection, and with intraoral radiographs at abutment connection and after at least 1 year of loading. A biopsy for histology and morphometry was taken at the first reentry operation. RESULTS: All but one of the procedures was successful (94.7%) as one maxillary sinus procedure (Group 2a) resulted in insufficient bone for implant placement. One of the 34 implants failed, giving an implant survival rate of 97.1% after 1 year. Implant stability measurements showed a mean stability of 71.9 ± 7.7 implant stability quotient (ISQ) at placement, which significantly increased to 75.3 ± 6.8 ISQ at abutment connection (p = .03). The average bone loss was 0.5 ± 0.7 mm during 1 year. Histology revealed new bone formation at the PB surface, which formed bridges between particles and between particles and preexisting bone. The presence of scalloped resorption lacunae and new osteons inside the particles indicated ongoing resorption/remodeling of the particles. The histomorphometric analyses showed that the total specimen area consisted of, in average, 56.5 ± 15.7% mineralized tissue of which 24.8 ± 13.9% of the total area was PB particles. CONCLUSION: This study showed good clinical results when using a PB substitute and barrier membranes for augmentation of the alveolar crest and maxillary sinus. Histology revealed bone condensation properties and indicated that the material can be resorbed with time.

Septal reshaping for exclusion of anteroseptal dyskinetic or akinetic areas.

BACKGROUND: Our purpose is to describe a technique for exclusion of anteroseptal dyskinetic or akinetic areas. METHODS: From January to December 2002, 22 consecutive patients with myocardial infarction following left anterior descending artery occlusion underwent septal reshaping. All of them were admitted for dyspnea. Eight patients were referred for angina. After a 5 to 8 cm apical incision, 2 U stitches were passed from inside to join the anterior wall to the septum, as high as possible, following the border of the scars. An oval Dacron patch was then sutured from the septum (end of the direct suture through the border with the inferior septum) to the anterior wall (between the healthy and the scarred wall) up to the new apex. Purpose of the procedure is to maintain a longitudinal size as similar as possible to the normal. The incision was closed in a double layer. RESULTS: No patient died and only one had acute renal failure. No patients had restrictive syndrome. After a mean follow-up of 6.7 +/- 3.6 months (3 to 15), mean New York Heart Association Class improved from 2.7 +/- 1.1 to 1.2 +/- 0.3 (p < 0.001). Echocardiographic results showed reduction of left ventricle volumes and normalization of the stroke volume. In patients with low ejection fraction (