Marginal bone loss around implants placed in maxillary native bone or grafted sinuses: a retrospective cohort study

Objectives To assess differences in marginal bone loss around implants placed in maxillary pristine bone and implants placed following maxillary sinus augmentation over a period of 3 years after functional loading. Material and methods Two cohorts of subjects (Group 1: Subjects who received sinus augmentation with simultaneous implant placement; Group 2: Subjects who underwent conventional implant placement in posterior maxillary pristine bone) were included in this retrospective study. Radiographic marginal bone loss was measured around one implant per patient on digitized panoramic radiographs that were obtained at the time of prosthesis delivery (baseline) and 12, 24, and 36 months later. The influence of age, gender, smoking habits, history of periodontal disease, and type of prosthetic connection (internal or external) on marginal bone loss was analyzed in function of the type of osseous support (previously grafted or pristine). Results A total of 105 subjects were included in this study. Cumulative radiographic marginal bone loss ranged from 0 mm to 3.9 mm after 36 months of functional loading. There were statistically significant differences in marginal bone loss between implants placed in grafted and pristine bone at the 12‐month assessment, but not in the subsequent progression rate. External prosthetic connection, smoking, and history of periodontitis negatively influenced peri‐implant bone maintenance, regardless of the type of osseous substrate. Conclusions Implants placed in sites that received maxillary sinus augmentation exhibited more marginal bone loss than implants placed in pristine bone, although marginal bone loss mainly occurred during the first 12 months after functional loading. Implants with external implant connection were strongly associated with increased marginal bone loss overtime.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102685/1/clr12122.pd

A Textbook of Advanced Oral and Maxillofacial Surgery

The scope of OMF surgery has expanded; encompassing treatment of diseases, disorders, defects and injuries of the head, face, jaws and oral cavity. This internationally-recognized specialty is evolving with advancements in technology and instrumentation. Specialists of this discipline treat patients with impacted teeth, facial pain, misaligned jaws, facial trauma, oral cancer, cysts and tumors; they also perform facial cosmetic surgery and place dental implants. The contents of this volume essentially complements the volume 1; with chapters that cover both basic and advanced concepts on complex topics in oral and maxillofacial surgery

Osteogenic marker expression in a grafted bone healing sheep model

Objectives: Successful healing of alveolar sockets after tooth extraction ensures positive outcomes for tooth replacement options. Using a sheep model the expression levels of key osteogenic markers for healing were compared over 16-weeks for empty and grafted sockets. Methods and Materials: First, second and third premolars were extracted from 30 sheep. The socket was either non-grafted for spontaneous healing (control) or grafted using Bio-Oss® and Bio-Gide® (test). After 4-, 8- and 16-weeks the sheep were euthanised and tissue samples collected. Histological analysis was undertaken and cellular localisation of receptor RANK, and ligands RANKL and OPG was determined using immunohistochemistry. mRNA expression levels for RANK, RANKL, OPG, Col1A1, TIMP3, Sp7 and Msx2 were determined using SYBR green RT2-qPCR assays. Results: Overall, more new woven bone was present in the test group compared to the control at all time points. Moderate immunopositive staining of RANK was associated with osteoblasts and osteoclasts in both groups at 4 weeks; with stronger osteoclast-associated staining in the test group at 8- and 16-weeks. Strong staining of RANKL associated with osteoblasts and osteoclasts was found in both groups at all time points. Initial strong OPG staining localised to the connective tissues decreased over time. Similar levels of mRNA expression in both groups for all seven osteogenic genes was found. The exception was RANK with expression levels lower in the test group compared to the control group at 4-weeks (P = 0.02). Sp7 was also expressed significantly lower in test group at 16-weeks (P = 0.04). Conclusion: Histologically more woven bone was present in test sockets likely due to the lower level of RANK expression resulting in decreased osteoclastic activity. There was, however, no statistically significant difference in the expression of the key markers of osteogenesis, RANKL and OPG between empty and grafted sockets at any time over the 16‑week period. There was also no difference in the expression of the transcription factor for osteoblast differentiation MSX2 or the ECM markers Col1A1 or TIMP3. Although Bio-Oss® is not osteoinductive it has osteoconductive and scaffolding properties, playing a role in alveolar ridge preservation and therefore, its use should be continued

PRELIMINARY FINDINGS OF A POTENZIATED PIEZOSURGERGICAL DEVICE AT THE RABBIT SKULL

The number of available ultrasonic osteotomes has remarkably increased. In vitro and in vivo studies have revealed differences between conventional osteotomes, such as rotating or sawing devices, and ultrasound-supported osteotomes (Piezosurgery®) regarding the micromorphology and roughness values of osteotomized bone surfaces. Objective: the present study compares the micro-morphologies and roughness values of osteotomized bone surfaces after the application of rotating and sawing devices, Piezosurgery Medical® and Piezosurgery Medical New Generation Powerful Handpiece. Methods: Fresh, standard-sized bony samples were taken from a rabbit skull using the following osteotomes: rotating and sawing devices, Piezosurgery Medical® and a Piezosurgery Medical New Generation Powerful Handpiece. The required duration of time for each osteotomy was recorded. Micromorphologies and roughness values to characterize the bone surfaces following the different osteotomy methods were described. The prepared surfaces were examined via light microscopy, environmental surface electron microscopy (ESEM), transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM) and atomic force microscopy. The selective cutting of mineralized tissues while preserving adjacent soft tissue (dura mater and nervous tissue) was studied. Bone necrosis of the osteotomy sites and the vitality of the osteocytes near the sectional plane were investigated, as well as the proportion of apoptosis or cell degeneration. Results and Conclusions: The potential positive effects on bone healing and reossification associated with different devices were evaluated and the comparative analysis among the different devices used was performed, in order to determine the best osteotomes to be employed during cranio-facial surgery

Management of bone defects with Bio-oss

Introduction: The defects in the alveolar bone might appear as a result of congenital malformations, traumatic injuries, periodontal disease, surgical traumas, chronic periapical changes and tumors from benign or malignant origin. The aim of this study was to provide solid and healthy area with application of Bio-Oss in the defect. Materials and methods: Based on the clinical diagnosisestablished by previously taken history, clinical examination and radiographic images oral-surgery interventions was made. To realize the aim of this work, augmentative material was implicated in the bone defects made in the patients after removal of follicular cyst, chronic periapical lesion, and parodontopathia. During the first and seventh day of the interventions, the patients have been followed through from aspect of possible development of local and general complications after the oral-surgery intervention. After period of one, three and six mount control x-ray was made. Results: Obtained results confirmed that: volume of the socket and defect of the bone was kept, fast revascularization was achieved, bone formation and slow resorption of the augmentative material was achieved, and period of normal healing without infection was also achieved. Conclusions: The augmentative materials used for treatment of bone defects besides their basic chemical and physical characteristics referring to their solubility in the body fluids, the transformation, modulation and resorption must be completely safe or secure, i.e. not to bring any risk of infection, immunological risk, physiological intolerance or inhibition of the process of restitutio ad integrum. In our study Bio-Oss was confirmed as augmentative material who had this characteristics. Keywords: bone defect, resorption of the bone, augmentative material, Bio-Os

Classic Reviews from Past Comprehensive Review Courses in Prosthodontics

https://deepblue.lib.umich.edu/bitstream/2027.42/154049/1/classic_reviews-vol1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154049/2/classic_reviews-vol2.pdfDescription of classic_reviews-vol1.pdf : Volume 1Description of classic_reviews-vol2.pdf : Volume

Image-Based Hybrid Scaffold Design for Multiple Tissue Regeneration Application in Periodontal Engineering.

Periodontal disease is a common chronic inflammatory disease, which if left untreated, can cause periodontal tissue breakdown. The periodontal complex is a micron-scaled, tooth-supporting structure with a complicated topology, which makes it difficult to predict and quantify periodontal tissue destruction. Unlike conventional assessment methods, 3-D micro-computed tomography provides very accurate, precise high resolution images of the periodontal topology. Using natural spatiotemporal landmarks to create a region-of-interest from the roof-of-furcation to the root-apex, volumetric image analysis of the bone-tooth interface was performed. The results demonstrated excellent examiner reproducibility and reliability (ICC>0.99 and CV<1.5%) for both linear and volumetric bone parameters. In an orthodontic tooth movement study, micro-CT quantified the activity of osteoprotegerin stimulation to prevent bone resorption and tooth mobility. Human alveolar bone core biopsies were analyzed to obtain mineral tissue density profiles in order to predict dental implant stability. Because of this high reproducibility and reliability, other wide-reaching applications have potential for predicting periodontal therapy outcomes, orthodontic tooth movement, as well as evaluation of clinical dental implant stability. A major challenge in periodontal tissue engineering is the control of periodontal tissue neogenesis; micron-scaled and complicated multi-interface regeneration with a functional architecture. To promote this compartmentalized, multiple tissue regeneration with perpendicularly-oriented periodontal ligament fiber, a multi-layered hybrid scaffold was designed and manufactured using the rapid prototyping technique. To produce a periodontium-like environment, the polymeric hybrid scaffold was assembled with a periodontal cell/tissue guidable micro-architecture; a highly porous bone region, a vertically-oriented PDL architecture, and a human tooth dentin slice. This complex was subcutaneously transplanted with untreated human PDL cells and BMP-7 transduced human gingival fibroblast cells using the ectopic model system. In spite of non-biomechanical loading conditions, this approach resulted in periodontal-structural similarity. There was a perpendicular/oblique orientation of the fibrous connective PDL cells/tissues to the dentin surface, and mineralized tissue formation without any mineralized tissue formation in the PDL interface of the hybrid scaffold at both the 3 and 6 weeks. This dissertation study provides potential for functional restoration of tissue interface neogenesis applications and shows promise for both pre-clinical and clinical applications for translational regenerative medicine.Ph.D.Biomedical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/78755/1/chanho_1.pd

Osseointegrated Oral implants

In the past, osseointegration was regarded to be a mode of implant anchorage that simulated a simple wound healing phenomenon. Today, we have evidence that osseointegration is, in fact, a foreign body reaction that involves an immunologically derived bony demarcation of an implant to shield it off from the tissues. Marginal bone resorption around an oral implant cannot be properly understood without realizing the foreign body nature of the implant itself. Whereas the immunological response as such is positive for implant longevity, adverse immunological reactions may cause marginal bone loss in combination with combined factors. Combined factors include the hardware, clinical handling as well as patient characteristics that, even if each one of these factors only produce subliminal trauma, when acting together they may result in loss of marginal bone. The role of bacteria in the process of marginal bone loss is smaller than previously believed due to combined defense mechanisms of inflammation and immunological reactions, but if the defense is failing we may see bacterially induced marginal bone loss as well. However, problems with loss of marginal bone threatening implant survival remains relatively uncommon; we have today 10 years of clinical documentation of five different types of implant displaying a failure rate in the range of only 1 to 4 %