Efficacy of the autogenous dentin graft for implant placement: a systematic review and meta-analysis of randomized controlled trials.

The aim of this study was to determine whether the autogenous dentin graft (ADG) shows comparable results and similar clinical performance to other graft materials when utilized for implant placement. Four databases were searched, and controlled human studies that applied autogenous dentin for implant surgery, comparing it with other bone grafts, were included. Nine articles met the inclusion criteria, five of which were randomized controlled trials and were included in the meta-analysis. ADG showed equivalent primary and secondary implant stability when compared to Bio-Oss (primary: mean difference -0.74, 95% confidence interval (CI) - 3.36 to 1.88, P = 0.58; secondary: mean difference - 1.29, 95% CI - 5.69 to 3.11, P = 0.57). The standardized mean difference (SMD) of marginal bone loss at 6 months and at the final follow-up (18 months) showed the two grafts to be similar (6 months: SMD -0.26, 95% CI -0.64 to 0.12, P = 0.18; final follow-up: SMD -0.12, 95% CI -0.50 to 0.26, P = 0.53), and survival after immediate implant placement was the same in the two groups: 97.37% and 97.30%, respectively. Incidences of complications with the autogenous dentin particles or blocks were in line with those of Bio-Oss or autogenous bone blocks, respectively. This meta-analysis indicates that the autogenous dentin graft is an effective option for bone augmentation around dental implants, with acceptable implant stability, marginal bone loss, and incidences of complications and failure.

Women Faculty Distressed: Descriptions and Consequences of Academic Contrapower Harassment.

Academic contrapower harassment (ACPH) occurs when someone with seemingly less power in an educational setting (e.g., a student) harasses someone more powerful (e.g., a professor). A representative sample of 289 professors from U.S. institutions of higher education described their worst incident with ACPH. Open-ended responses were coded using a keyword text analysis. Compared to the experiences of men faculty, women faculty reported that students were more likely to challenge their authority, argue or refuse to follow course policies, and exhibit disrespectful or disruptive behaviors. Although sexual harassment was uncommon, men faculty were more likely than women faculty to recount such incidents. Women faculty reported significantly more negative outcomes as a result of ACPH (e.g., anxiety, stress-related illness, difficulty concentrating, wanting to quit) than men faculty, and negative outcomes were most likely to result from ACPH involving intimidation, threats, or bullying from students. Implications for the prevention and reporting of ACPH are discussed.

The progressive ankylosis protein regulates cementum apposition and extracellular matrix composition.

BACKGROUND/AIMS: Tooth root cementum is sensitive to modulation of inorganic pyrophosphate (PP(i)), an inhibitor of hydroxyapatite precipitation. Factors increasing PP(i) include progressive ankylosis protein (ANK) and ectonucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) while tissue nonspecific alkaline phosphatase hydrolyzes PP(i). Studies here aimed to define the role of ANK in root and cementum by analyzing tooth development in Ank knock-out (KO) mice versus wild type. MATERIALS AND METHODS: Periodontal development in KO versus control mice was analyzed by histology, histomorphometry, immunohistochemistry, in situ hybridization, electron microscopy, and nanoindentation. Cementoblast cultures were used in vitro to provide mechanistic underpinnings for PP(i) modulation of cell function. RESULTS: Over the course of root development, Ank KO cervical cementum became 8- to 12-fold thicker than control cervical cementum. Periodontal ligament width was maintained and other dentoalveolar tissues, including apical cementum, were unaltered. Cervical cementum uncharacteristically included numerous cells, from rapid cementogenesis. Ank KO increased osteopontin and dentin matrix protein 1 gene and protein expression, and markedly increased NPP1 protein expression in cementoblasts but not in other cell types. Conditional ablation of Ank in joints and periodontia confirmed a local role for ANK in cementogenesis. In vitro studies employing cementoblasts indicated that Ank and Enpp1 mRNA levels increased in step with mineral nodule formation, supporting a role for these factors in regulation of cementum matrix mineralization. CONCLUSION: ANK, by modulating local PP(i), controls cervical cementum apposition and extracellular matrix. Loss of ANK created a local environment conducive to rapid cementogenesis; therefore, approaches modulating PP(i) in periodontal tissues have potential to promote cementum regeneration.

Ablation of systemic phosphate-regulating gene fibroblast growth factor 23 (Fgf23) compromises the dentoalveolar complex.

Fibroblast growth factor-23 (FGF23) is a hormone that modulates circulating phosphate (P(i)) levels by controlling P(i) reabsorption from the kidneys. When FGF23 levels are deficient, as in tumoral calcinosis patients, hyperphosphatemia ensues. We show here in a murine model that Fgf23 ablation disrupted morphology and protein expression within the dentoalveolar complex. Ectopic matrix formation in pulp chambers, odontoblast layer disruption, narrowing of periodontal ligament space, and alteration of cementum structure were observed in histological and electron microscopy sections. Because serum P(i) levels are dramatically elevated in Fgf23(-/-), we assayed for apoptosis and expression of members from the small integrin-binding ligand, N-linked glycoprotein (SIBLING) family, both of which are sensitive to elevated P(i) in vitro. Unlike X-linked hypophosphatemic (Hyp) and wild-type (WT) specimens, numerous apoptotic osteocytes and osteoblasts were detected in Fgf23(-/-) specimens. Further, in comparison to Hyp and WT samples, decreased bone sialoprotein and elevated dentin matrix protein-1 protein levels were observed in cementum of Fgf23(-/-) mice. Additional dentin-associated proteins, such as dentin sialoprotein and dentin phosphoprotein, exhibited altered localization in both Fgf23(-/-) and Hyp samples. Based on these results, we propose that FGF23 and (P(i)) homeostasis play a significant role in maintenance of the dentoalveolar complex.

Aberrant cementum phenotype associated with the hypophosphatemic hyp mouse.

BACKGROUND: Cementogenesis is sensitive to altered local phosphate levels; thus, we hypothesized a cementum phenotype, likely of decreased formation, would be present in the teeth of X-linked hypophosphatemic (Hyp) mice. Mutations in the phosphate-regulating gene with homologies to endopeptidases on the X chromosome (Phex) cause X-linked hypophosphatemia, characterized by rickets, osteomalacia, and hypomineralized dentin formation, a phenotype recapitulated in the Hyp mouse homolog. Here, we report a developmental study of tooth root formation in Hyp mouse molars, focusing on dentin and cementum. METHODS: Light and transmission electron microscopy were used to study molar tissues from wild-type (WT) and Hyp mice. Demineralized and hematoxylin and eosin-stained tissues at developmental stages 23 to 96 days postcoital (dpc) were examined by light microscopy. Immunohistochemistry methods were used to detect bone sialoprotein (BSP) distribution in Hyp and WT mouse molar tissues, and transmission electron microscopy was used to study similar molar tissues in the non-demineralized state. RESULTS: Dentin in Hyp mice exhibited mineralization defects by 33 dpc, as expected, but this defect was partially corrected by 96 dpc. In support of our hypothesis, a cementum phenotype was detected using a combination of immunohistochemistry and transmission electron microscopy, which included thinner BSP-positive staining within the cementum, discontinuous mineralization, and a globular appearance compared to WT controls. CONCLUSION: Mutations in the phosphate-regulating Phex gene of the Hyp mouse resulted in defective cementum development.

TGF-beta1 Inhibits TLR-mediated odontoblast responses to oral bacteria.

TGF-beta1 exerts diverse functions in tooth development and tissue repair, but its role in microbial defenses of the tooth is not well-understood. Odontoblasts extending their cellular processes into the dentin are the first cells to recognize signals from TGF-beta1 and bacteria in carious dentin. This study aimed to determine the role of TGF-beta1 in modulating odontoblast responses to oral bacteria. We show that these responses depend upon the expression levels of microbial recognition receptors TLR2 and TLR4 on the cell surface. Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum activated both TLRs, but TLR4 played a greater role. Lack of cell-surface TLR2 was associated with poor response to Streptococcus mutans, Enterococcus faecalis, and Lactobacillus casei. TGF-beta1 inhibited TLR2 and TLR4 expression and attenuated odontoblast responses. Our findings suggest that the balance between TLR-mediated inflammation and TGF-beta1 anti-inflammatory activity plays an important role in pulpal inflammation.

Restorations using osseointegrated implants with resilient attachments.

This article presents a clinical report of the prosthodontic treatment of a patient with a partially edentulous mandible. Osseointegrated titanium implants and resilient attachments for overdentures were used to retain and stabilize a mandibular overdenture that restored the patient's occlusion. This provided a simple and economical solution to retention and stability problems for a patient with a partially edentulous mandible.

A conservative fixed partial denture: a clinical report.

The restoration of a patient's edentulous area with a three-unit fixed partial denture is described. The denture consisted of an etched-metal bonded retainer and metal ceramic pontic with a nonrigid connector in combination with a conventional inlay retainer. The incorporation of a nonrigid connector permitted the use of dissimilar metals and cements with retainers of different retention potentials. This technique provides minimal reduction of tooth structure with supragingival margins for improved periodontal health.

A two-stage impression technique for custom facial prostheses.

A two-stage impression technique that uses polyvinyl siloxane and irreversible hydrocolloid in a custom impression tray is described. The technique records the tissues to be contacted by the facial prosthesis with minimal distortion with the patient in an upright position and facial musculature at rest. The procedure is simple, accurate, and it eliminates some of the shortcomings of other techniques.