Peri-implant tissue conditions following transcrestal and lateral sinus floor elevation: 3-year results of a bi-center, randomized trial

Objectives The present study was performed to comparatively evaluate the peri-implant bone stability and conditions of marginal tissues at 3 years following transcrestal and lateral sinus floor elevation (tSFE and lSFE, respectively). Materials and methods Patients included in a parallel-arm randomized trial comparatively evaluating tSFE and lSFE were recalled at 3 years post-surgery. Twenty-one and 24 patients in tSFE and lSFE groups, respectively, participated in the follow-up visit. Peri-implant bone support was evaluated as the proportion of the entire implant surface in direct contact with the radiopaque area (totCON%) on 3-year periapical radiographs. The conditions of the marginal peri-implant tissues at 3-year visit were classified as peri-implant health, peri-implant mucositis, or peri-implantitis. Results At 3 years, both groups showed an implant survival rate of 100%. Median totCON% was stable at 3 years, being 100% in both groups (p = 0.124). Peri-implant health and mucositis were diagnosed in 10 (47.6%) and 11 (52.4%) patients, respectively, in the tSFE group, and in 8 (33.3%) and 16 (66.7%) subjects, respectively, in the lSFE group (p = 0.502). Conclusions At 3 years following surgery, implants placed concomitantly with tSFE and lSFE fully maintain peri-implant bone support. Peri-implant mucositis was the most prevalent condition, with a similar prevalence between groups. Clinical relevance. Based on 3-year data on peri-implant bone support and prevalence of peri-implant diseases, the study suggests that tSFE and lSFE represent two equally valid options for the rehabilitation of the posterior maxilla. ClinicalTrials.gov ID: NCT02415946.

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.

The Effect of Different Implant-Abutment Mis-Matches on Stress Distribution: A 3-Dimensional Finite Element Study

Platform-switching reduces peri-implant marginal bone loss (MBL), and the aim of this study was to compare the effect of platform-switching on stress within crestal bone using different implant-abutment mis-matches (0.65 and 1mm) under two different vertical loads (30 N vs 200 N) for implants placed in posterior jaw sites. 3-D modeling software was used for an implant of 4.5mm diameter and 13mm length. Molars were modeled using CT images of bone density in human maxilla (D3 bone) and mandible (D2 bone). Collected data were analyzed using CATIA software. In posterior mandible, stress of 30 N force with platform mis-matches of 0.65 or 1mm were 2.920 and 2.440 MPa respectively. Using 200 N force, values increased to 19.44 and 16.30 MPa. In posterior maxilla and 30 N force, stresses with mis-matches of 0.65 and 1mm were 3.77 and 3.18 MPa respectively increasing to 25.14 & 20.17 with 200 N force. The effect can be predicted to be greatest as the mis-match increases with implants placed into lower quality bone (posterior maxilla with D3 quality).

Removal of Inflammatory Tissue/Product by Sinus Membrane Puncturing during Lateral Sinus Augmentation in Asymptomatic Patients with Severely Opacified Sinuses: A Case Series

It is generally recommended that severe sinus membrane (SM) thickening should be treated prior to maxillary sinus augmentation (MSA), but during lateral MSA, inflammatory tissue/product may be removed by puncturing the SM. The present case report demonstrates surgical experience of lateral MSA with simultaneous inflammatory tissue/product removal for sinuses with severe opacification. In three patients requiring dental implant placement in the posterior maxilla, severe SM thickening was observed, but they were asymptomatic. The SM was gently elevated, followed by puncturing the SM, removing inflammatory tissue via the punctured site, draining, and thorough saline irrigation. Then, bone grafting and implant placement were performed with extra care not to spread bone substitute material into the punctured area. The postoperative pain following this procedure was more severe as compared to conventional MSA. Nasal bleeding was reported for 2–3 days. All implants were successfully integrated and demonstrated adequate function. Tissue samples retrieved during the surgery showed advanced inflammatory cell infiltration. The follow-up cone-beam computed tomographic scans revealed a significant reduction in SM thickening. In conclusion, inflammatory tissue/product removal by puncturing the SM can be applied during lateral MSA. However, more data should be needed due to the empirical nature of the present outcomes.

Extraarticular joint ankylosis: a rare presentation

Pseudoankylosis is a rare condition that causes inability to open the mouth due to condition related to outside of the temporomandibular joint. Most literature refers to this hypomobility disorder, a result of fusion of the zygomatic bone to the coronoid process, and very rarely is insidious coronoid hyperplasia causing mechanical interference with the posterior maxilla has been reported. We present a case of a 45-year-old woman, who presented with coronoid malformation and overgrowth resulting in progressive decrease in mouth opening. She was managed with coronoidectomy, following which good mouth opening was obtained. In this paper we discuss about the diagnosis and management of this rare disorder.