Jinny Kwak

Long-term stability of anterior open-bite treatment by intrusion of maxillary posterior teeth

INTRODUCTION Anterior open bite results from the combined influences of skeletal, dental, functional, and habitual factors. The long-term stability of anterior open bite corrected with absolute anchorage has not been thoroughly investigated. The purpose of this study was to examine the long-term stability of anterior open-bite correction with intrusion of the maxillary posterior teeth. METHODS Nine adults with anterior open bite were treated by intrusion of the maxillary posterior teeth. Lateral cephalographs were taken immediately before and after treatment, 1 year posttreatment, and 3 years posttreatment to evaluate the postintrusion stability of the maxillary posterior teeth. RESULTS On average, the maxillary first molars were intruded by 2.39 mm (P<0.01) during treatment and erupted by 0.45 mm (P<0.05) at the 3-year follow-up, for a relapse rate of 22.88%. Eighty percent of the total relapse of the intruded maxillary first molars occurred during the first year of retention. Incisal overbite increased by a mean of 5.56 mm (P<0.001) during treatment and decreased by a mean of 1.20 mm (P<0.05) by the end of the 3-year follow-up period, for a relapse rate of 17.00%. Incisal overbite significantly relapsed during the first year of retention (P<0.05) but did not exhibit significant recurrence between the 1-year and 3-year follow-ups. CONCLUSIONS Most relapse occurred during the first year of retention. Thus, it is reasonable to conclude that the application of an appropriate retention method during this period clearly enhances the long-term stability of the treatment.

The use of BMP-2 coupled – Nanosilver-PLGA composite grafts to induce bone repair in grossly infected segmental defects

Healing of contaminated/infected bone defects is a significant clinical challenge. Prevalence of multi-antibiotic resistant organisms has renewed interest in the use of antiseptic silver as an effective, but less toxic antimicrobial with decreased potential for bacterial resistance. In this study, we demonstrated that metallic nanosilver particles (with a size of 20-40nm)-poly(lactic-co-glycolic acid) (PLGA) composite grafts have strong antibacterial properties. In addition, nanosilver particles-PLGA composite grafts did not inhibit adherence, proliferation, alkaline phosphatase activity, or mineralization of ongrowth MC3T3-E1 pre-osteoblasts compared to PLGA controls. Furthermore, nanosilver particles did not affect the osteoinductivity of bone morphogenetic protein 2 (BMP-2). Infected femoral defects implanted with BMP-2 coupled 2.0% nanosilver particles-PLGA composite grafts healed in 12 weeks without evidence of residual bacteria. In contrast, BMP-2 coupled PLGA control grafts failed to heal in the presence of continued bacterial colonies. Our results indicate that nanosilver of defined particle size is bactericidal without discernable in vitro and in vivo cytotoxicity or negative effects on BMP-2 osteoinductivity, making it an ideal antimicrobial for bone regeneration in infected wounds.

Topographic distribution area of the infraorbital nerve

The infraorbital nerve (ION) supplies the skin and mucous membranes of the middle portion of the face. This nerve is vulnerable to injury during surgical procedures of mid-face. Severe pain and loss of sense are noted in patients whose infraorbital nerve is either entirely or partially lost after these surgeries. We investigated the distribution area and topography of the ION, about which little is currently known, by dissecting 43 hemifaces of Korean cadavers. The ION produced four main branches, the inferior palpebral, internal nasal, external nasal, and superior labial branches. The inferior palpebral branch was generally bifurcated, giving off a medial and a lateral branch (58.1%). The internal nasal branch ran superior to the depressor septi muscle, along the ala of the nose. It supplied the skin of the philtrum and gave off a terminal branch that supplied the nasal septum and the vestibule of the nose. The external nasal branch was distributed diversely supplying areas between the root and the ala of the nose. The superior labial branch was the largest branch of the ION produced the most subbranches. These subbranches were divided into the medial and lateral branches depending upon the area that they supplied.

Association of Condylar Bone Quality with TMJ Osteoarthritis.

The etiology and treatment of temporomandibular joint (TMJ) osteoarthritis (TMJOA) remain complex and unclear. Based on clinical observations, we hypothesized that low condylar bone quality is significantly correlated with TMJOA and explored this association in a cross-sectional study with human patients. A total of 254 postmenopausal female participants were included in this study. Radiographic findings from cone beam computed tomography (CBCT) and clinical symptoms were used to classify each TMJ data sample as healthy control (n = 124) or TMJOA (n = 130). Condylar bone mineral density (BMD) (computed tomography Hounsfield unit [CT HU]) and bone volume fraction (BV/TV) were measured and modeled as predictors of healthy control versus TMJOA status in multilevel logistic regression analyses. Both CT HU (adjusted odds ratio [AOR] = 0.9989, interquartile odds ratio [IOR] = 0.4206) and BV/TV (AOR= 0.8096, IOR = 0.1769) were negatively associated with TMJOA (P = 0.049, 0.011, respectively). To assess the diagnostic performance of CT HU and BV/TV for identification of TMJOA, receiver operating characteristic (ROC) curves were plotted. The estimated areas under the curve (AUC) were 0.6622 for BV/TV alone, 0.6074 for CT HU alone, and 0.7136 for CT HU and BV/TV together. The model incorporating CT HU and BV/TV together had a significantly higher AUC than the models using BV/TV alone (P = 0.038) or HU alone (P = 0.021). In conclusion, we found that low condylar bone quality was significantly correlated with TMJOA development and that condylar CT HU and BV/TV can be used together as a potential diagnostic tool for TMJOA. Careful clinical evaluation of the condyle coupled with appropriate radiographic interpretation would thus be critical for the early detection of TMJOA.