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Biomedical subjects

Mark V Thomas

Publications and source records attributed to Mark V Thomas.

8 recordsLinked to original sources
PubMed2006

Implant surfaces.

Available in many shapes, sizes, and lengths, dental implants are also crafted from different materials with different surface proper-ties. Among the most desired characteristics of an implant are those that ensure that the tissue-implant interface will be established quickly and then will be firmly maintained. Because many variables affect oral implants, it is sometimes difficult to reliably predict the likelihood of an implant's success. It is especially difficult to assess whether the various modifications in the latest implants deliver improved performance. This article focuses primarily on important surface characteristics and their potential effects on the performance of dental implants.

Biocompatible Materials↗
PubMed2006

Implant anchorage in orthodontic practice: the Straumann Orthosystem.

Dental implants have been used to provide orthodontic anchorage. This article provides an overview of the Straumann Orthosystem implant system (Institut Straumann, Waldenburg, Switzerland) and its application, including the anatomy of the bony palate and contiguous structures. Considerations in placement of the Orthosystem implant include the avoidance of contiguous anatomic structures such as the nasal cavity, the degree of ossification of the palatal suture, and the quality and quantity of bone in the proposed implant site, all of which are discussed in this article.

Bone Density↗
PubMed2006

Evidence-based decision-making: implants versus natural teeth.

The clinician is increasingly confronted with the dilemma of whether to use implants or so-called "traditional" dental interventions. Given the high predictability of implants, their use should be considered routine. The survival and success rates reported by many investigators often exceed the success rates of some forms of heroic treatment. Findings from well-designed trials must be used to guide clinical decision-making. In this article, the authors review studies of outcomes related to one particular implant system and compare these results to those reported for various forms of endodontic therapy and tissue-supported mandibular complete dentures. The results suggest that implant restorations of the system in question have a level of predictability equal to or greater than that for traditional dental treatment.

Crowns↗
PubMed2006

Salivary biomarkers of existing periodontal disease: a cross-sectional study.

BACKGROUND: The authors conducted a study to determine if salivary biomarkers specific for three aspects of periodontitis--inflammation, collagen degradation and bone turnover--correlate with clinica features of periodontal disease. METHODS: The relationship between periodontal disease and the levels of interleukin-1 beta (IL-1beta), matrix metalloproteinase (MMP)-8, and osteoprotegerin (OPG) in whole saliva of 57 adults (28 "case" subjects with moderate-to-severe periodontal disease and 29 healthy control subjects) was examined in a case-control trial. RESULTS: Mean levels of IL-1beta and MMP-8 in saliva were significantly higher in case subjects than in controls. Both analytes correlated with periodontal indexes, whereas, after adjustment for confounders, OPG did not. Elevated salivary levels of MMP-8 or IL-1beta (more than two standard deviations above the mean of the controls) significantly increased the risk of periodontal disease (odds ratios in the 11.3-15.4 range). Combined elevated salivary levels of MMP-8 and IL-1beta increased the risk of experiencing periodontal disease 45-fold, and elevations in all three biomarkers correlated with individual clinical parameters indicative of periodontal disease. CONCLUSION: Salivary levels of MMP-8 and IL-1beta appear to serve as biomarkers of periodontitis. CLINICAL IMPLICATIONS: Qualitative changes in the composition of salivary biomarkers could have significance in the diagnosis and treatment of periodontal disease.

Adult↗
PubMed2005

Bioactive glass three decades on.

Bioglasses were first introduced in the early 1970s and since have found wide use in dentistry. The original 45S5 bioglass, as described by Hench, is a silica-based melt-derived glass characterized by a Si02 content of less than 60%, a high Na2O and CaO content, and a high CaO:P2O5 ratio. Bioactivity has been defined as the ability of an implant to form a bond with living tissue. These glasses exhibit bone bonding, a phenomenon also observed with other bioactive ceramics. This process is a result of the surface reactive silica, calcium, and phosphate groups that are characteristic of these materials. Silica is believed to play a critical role in bioactivity. Bioactive glass is a very biocompatible material. There is a good deal of experimental data supporting its use in a variety of clinical applications, including ridge preservation, sinus augmentation, and the repair of periodontal bone defects. There are limitations inherent in the bioglass products that are currently available. They are granular in nature and cannot be depended upon to serve reliably as space-making devices. Although they are quite biocompatible and exhibit bone bonding, bioglasses are not osteoinductive and are not capable of forming bone in ectopic sites (although they can be used to deliver osteopromotive growth factors). The range of applications for these products could be extended if the material could be made in various space-making forms. Incorporation or coating with osteogenic agents such as growth factors might be worthwhile. The full potential of bioactive glasses has yet to be fully realized.

Animals↗
PubMed2005

Calcium sulfate: a review.

Calcium sulfate has a long history of use in medicine and dentistry. It exists in two forms (alpha and beta), which differ greatly in physical properties. It has been used in bone regeneration as a graft material and graft binder/extender and as a barrier in guided tissue regeneration. It is an unusually biocompatible material and is completely resorbed following implantation. It does not evoke a significant host response and creates a calcium-rich milieu in the area of implantation. These calcium ions may provide some stimulation to osteoblasts, which may account for some of the positive results reported with the material. Calcium sulfate can be used as a delivery vehicle for growth factors and antibiotics, although this application has not been thoroughly exploited in the clinical setting. It has been shown that tissue will often migrate over calcium sulfate if primary closure cannot be obtained, which provides further evidence of its biocompatibility. The raw material from which calcium sulfate is made is relatively inexpensive and abundant. Despite these advantages, calcium sulfate has never attracted the same degree of research interest as have other biomaterials. Recently, however, it has enjoyed a resurgence of sorts in the areas of periodontology, sinus augmentation, and orthopedic surgery. Future research must be directed toward improving handling characteristics and strength, while preserving the biocompatibility of the material.

Animals↗