Er:YAG laser in the clinical management of severe peri-implantitis: a case report.

Peri-implantitis is bacterial infections of peri-implant supporting tissues, involving the peri-implant bone. Several treatment protocols have been tested in clinical practice with variable efficacy. The clinical management of peri-implantitis aims for elimination of plaque and calculus, decontamination of the failing implant surface, and regeneration of lost bone tissue. Surface decontamination is an important part of all suggested treatments. This can be accomplished with the use of chemical agents (eg, chlorhexidine) or mechanical (eg, ultrasonic) or photonic (eg, laser) devices. In this report, we present a case of severe peri-implantitis that was successfully managed with a combined nonsurgical and surgical approach. Implant surface debridement/decontamination of the implant surface was achieved with an erbium-doped yttrium aluminium garnet (Er:YAG) laser device.

Comparison of two bone substitute biomaterials consisting of a mixture of fibrin sealant (Tisseel) and MBCP (TricOs) with an autograft in sinus lift surgery in sheep.

OBJECTIVES: The aim of this study was to assess the efficacy and safety of macroporous biphasic calcium phosphate (MBCP())/fibrin grafts (TricOs((R)))/(Tisseel((R))) for sinus lift augmentation in sheep. Autologous bone grafts were used as a positive control, and dental implants were placed to assess the efficiency of the composite. MATERIALS AND METHODS: A total of 12 adult sheep (24 maxillary sinuses) were randomized to receive sinus lift augmentation with MBCP()/fibrin grafts obtained by either simultaneous or sequential addition of thrombin and fibrinogen to MBCP(), or autologous bone grafts. Six months post-sinus lift surgery, dental implants were placed. At 6 months post-sinus lift and 3 months after dental implant placement, the characteristics of newly formed bone and dental implant stability were assessed. The methods used were radiography, scanning electron microscopy, light microscopy, micro-CT analysis, radio frequency analysis (RFA), and image analysis. RESULTS: There were no clinical adverse events in the post-operative period. New bone formation was similar for MBCP()/fibrin grafts and autografts at 21-20% and 20%, respectively, at 6 months, and at 34-35% and 35%, respectively, at 9 months. Implantability of dental implants was better at the time of placement with MBCP()/fibrin grafts than autografts at 81-88% and 69%, respectively. Three months after placement, RFA showed better implantability with MBCP()/fibrin grafts than with autografts at 75-82% and 71%, respectively. The bone contact measurements were around 50% for the three groups, without significant differences. CONCLUSIONS: This study shows that following sinus lift augmentation in sheep, MBCP()/fibrin grafts support new bone formation that is comparable to autografts, while providing better support for the dental implants.

Correlating implant stability to bone structure.

OBJECTIVES: The aim of this study was to demonstrate a possible correlation between bone microarchitecture and primary implant stability. MATERIAL AND METHODS: Twenty-two implants (Ankylos((R)) and Straumann((R))) were inserted into the maxillae and mandibles of human cadavers. Bone structure was determined by computed tomography in three specimens (male, age 53; female, 67; female, 80). A strict clinical protocol was used for implantation. Primary implant stability was measured by resonance frequency analysis (Osstell Mentor). The bone structure was analyzed by micro-computed tomography (CT). Bone histomorphometrical parameters were calculated and correlated to primary implant stability. RESULTS: Implant stability quotients (ISQ) ranged from 50 to 70% depending on the specimens and sites. Histomorphometry indicated differences in the bone microstructures of the specimens. However, ISQ values were not related to trabecular bone histomorphometrical parameters. The sole correlation was found between ISQ values and cortical bone thickness. CONCLUSION: This study confirms the relevance for primary stability of cortical thickness around implants. The thickness of cortical bone can be assessed using a standard clinical CT.

Clinical Safety of a New Synthetic Resorbable Dental Membrane: A Case Series Study.

Dental membranes are commonly used in oral and maxillofacial surgery for the regeneration of small osseous defects. A new synthetic resorbable membrane has recently demonstrated its biocompatibility and bone regeneration capacity in preclinical studies. This membrane is made of poly(D,L-lactic/glycolic acid 85/15), has a bi-layered structure with a dense film to prevent gingival epithelial cell invasion, and a microfibrous layer to support osteogenic cells and bone healing. This membrane completely degrades by hydrolysis in 4 to 6 months without signs of inflammation. Based on this research, a clinical study was conducted to evaluate the safety of the new membrane in guided tissue regeneration (GTR). In total, 26 patients (age: 50.5 ± 12.4, min-max 31-72 years; male/female 42/58%) were operated on at 7 independent private dental practices. Dental surgeons used the membrane together with various bone fillers in GTR for immediate and delayed implant placement (23 cases, 88%) and, to a lesser extent, socket preservation (2 cases, 8%) and alveolar crest augmentation (1 case, 4%). Surgeons reported an easy placement of the membrane (satisfaction index: 3.8/5). Fourteen days postsurgery, 15 patients had no pain while the others declared minimal pain (verbal rating scale: 2.2/10), and none had minor or serious complications related to the membrane. Exposure of the membrane without loosening the biomaterial granules was observed in 3 cases while mucosa healed normally over time. At 4 months postimplantation, no infection or mucosal inflammation was reported, and the overall dentist satisfaction with the clinical performance of the membrane was 4.5/5 on average. This clinical study demonstrated that the new synthetic resorbable membrane is safe for guided bone tissue regeneration in various dental surgery indications.

Ectopic bone formation by microporous calcium phosphate ceramic particles in sheep muscles.

Calcium phosphate ceramics are widely used in bone reconstructive surgery because of their osteconductive properties. However, these materials generally lack osteoinductive properties required to support bone healing in large defects. In this article, we study the osteoinductive potential of calcium phosphate ceramic particles implanted for 6 months into the dorsal muscles of eight adult female sheep. Microporous biphasic calcium phosphate (MBCP) granules of 1-2 mm composed of hydroxyapatite and beta-tricalcium phosphate (60/40) had macropores of 450 microm, micropores of 0.43 microm, and a specific surface area of 1.8 m(2)/g. After 6 months in the back muscles of sheep, the explants composed of MBCP granules were hard and encapsulated by normal muscle tissue. Ectopic bone formation with Haversian structures was observed in close contact with the MBCP granules in histological sections. Back-scattered electron microscopy and micro-computed tomography indicated that approximately 10% of well-mineralized bone with mature osteocytes had formed between or upon the granules. The ectopic bone showed trabeculae bridging the MBCP granules. Both the number and thickness of the trabeculae formed between the MBCP particles were comparable to those measured in spongious bone. The overall results therefore confirmed the presence of mature bone after intramuscular implantation of MBCP granules. The different hypotheses explaining ectopic bone formation induced by MBCP granules are discussed. Synthetic bone substitutes with osteoinductive properties could be used in bone reconstructive surgery.

Bone tissue formation in sheep muscles induced by a biphasic calcium phosphate ceramic and fibrin glue composite.

Some biomaterials are able to induce ectopic bone formation in muscles of large animals. The osteoinductive potential of macro- micro-porous biphasic calcium phosphate (MBCP) ceramic granules with fibrin glue was evaluated by intramuscular implantation for 6 months in six adult female sheep. The MBCP granules were 1-2 mm in size and were composed of hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP) in a 60/40 ratio. The fibrin glue was composed of fibrinogen, thrombin and other biological factors. After 6 months of implantation in the dorsal muscles of sheep, the explants were rigid. Histology, back-scattered electron microscopy and micro-computed tomography of the implants indicated that approximately 12% of mineralized bone had formed in between the MBCP granules. The ectopic bone appeared well-mineralized with mature osteocytes and Haversian structures. In addition, the number and thickness of bone trabeculae formed in between the MBCP particles were similar to those measured in trabecular bone in sheep. The overall results therefore confirmed the formation of well-mineralized ectopic bone tissue after intramuscular implantation of MBCP/fibrin glue composites. These bone substitutes exhibiting osteoinductive properties could be used for the reconstruction of large bone defects.

Osteogenic properties of calcium phosphate ceramics and fibrin glue based composites.

Calcium phosphate (Ca-P) ceramics are currently used in various types of orthopaedic and maxillofacial applications because of their osteoconductive properties. Fibrin glue is also used in surgery due to its haemostatic, chemotactic and mitogenic properties and also as scaffolds for cell culture and transplantation. In order to adapt to surgical sites, bioceramics are shaped in blocks or granules and preferably in porous forms. Combining these bioceramics with fibrin glue provides a mouldable and self-hardening composite biomaterial. The aim of this work is to study the osteogenic properties of this composite material using two different animal models. The formation of newly formed bone (osteoinduction) and bone healing capacity (osteconduction) have been study in the paravertebral muscles of sheep and in critical sized defects in the femoral condyle of rabbits, respectively. The different implantations sites were filled with composite material associating Ca-P granules and fibrin glue. Ca-P granules of 1-2 mm were composed with 60% of hydroxyapatite and 40% of beta tricalcium phosphate in weight. The fibrin glue was composed of fibrinogen, thrombin and other biological factors. After both intramuscular or intraosseous implantations for 24 weeks and 3, 6, 12 and 24 weeks, samples were analyzed using histology and histomorphometry and mechanical test. In all cases, the newly formed bone was observed in close contact and around the ceramic granules. Depending on method of quantification, 6.7% (with BSEM) or 17% (with micro CT) of bone had formed in the sheep muscles and around 40% in the critical sized bone rabbit defect after 24 weeks. The Ca-P/fibrin material could be used for filling bone cavities in various clinical indications.