Pil-Young Yun

Comparative Study Between Resorbable and Nonresorbable Plates in Orthognathic Surgery

PURPOSEnThe purpose of the present study was to evaluate the clinical application of resorbable and nonresorbable plates for correction of facial asymmetry.nnnPATIENTS AND METHODSnA total of 272 patients who had undergone orthognathic surgery were enrolled. The site of osteotomy was fixed using a nonresorbable plate in group I (n = 152) and using a resorbable plate in group II (n = 120). The postoperative complications included postoperative anterior open bite, infection, temporomandibular joint dysfunction, and postoperative relapse. The incidence of all complications was examined.nnnRESULTSnThe surgical outcome was successful in 269 patients (98.89%). Of the 152 patients with a titanium plate, 13 (8.6%) developed complications. Of the 120 patients with a resorbable plate, 22 (18.3%) developed complications. A greater degree of postoperative open bite and a trend toward relapse were observed in patients cases in which an absorbable fixation plate was used. Postoperative infection occurred in patients with an absorbable fixation plate.nnnCONCLUSIONnOn the basis of these data, we have concluded that an absorbable fixation plate should be used instead of a titanium fixation plate in indicated patients.

Cardiopulmonary coupling analysis: changes before and after treatment with a mandibular advancement device

PurposeThe aim of this study is to evaluate the changes of sleep quality in patients using a mandibular advancement device (MAD) for obstructive sleep apnea (OSA) based upon cardiopulmonary coupling (CPC).MethodsA total of 52 patients (mean age 53.7u2009±u20099.6xa0years, range 33–74xa0years) were included in this study. Of them, there were 47 males (90.4xa0%). All subjects were diagnosed with OSA after in-laboratory full-night polysomnography and reevaluated after 3-month use of a MAD. At baseline, apnea-hypopnea index (AHI) was 33.6u2009±u200917.0, Epworth sleepiness scale was 10.5u2009±u20094.8, and Pittsburgh sleep quality index was 5.8u2009±u20092.8. The CPC parameters were extracted from single-lead electrocardiography of polysomnography. We compared CPC parameters at baseline with those after 3-month use of a MAD.ResultsAll respiratory indices improved with the use of MAD. However, there were no differences in the sleep architectures except N3 sleep (3.7u2009±u20094.3 to 6.9u2009±u20096.4xa0%, pu2009<u20090.001). The CPC parameters showed a significant improvement with the use of MAD. Low-frequency coupling (59.5u2009±u200916.1 to 47.7u2009±u200914.8xa0%, pu2009<u20090.001) and elevated low-frequency coupling (44.6u2009±u200918.4 to 32.6u2009±u200915.7xa0%, pu2009<u20090.001) significantly decreased. High-frequency coupling (28.6u2009±u200916.0 to 36.5u2009±u200915.7xa0%, pu2009=u20090.004) and very low frequency coupling (11.7u2009±u20097.2 to 15.3u2009±u20096.6xa0%, pu2009=u20090.028) significantly increased. The change of AHI significantly correlated with changes of the CPC parameters: negatively correlated with high-frequency coupling change (ru2009=u2009−0.572, pu2009<u20090.001) and positively correlated with low-frequency and elevated low-frequency coupling changes (ru2009=u20090.604 and 0.497, respectively; pu2009<u20090.001 in both). However, the changes of Epworth sleepiness scale and Pittsburgh sleep quality index after MAD therapy showed no significant correlation with the changes in the CPC parameters.ConclusionsTo our knowledge, this is the first study to evaluate the quality of sleep in patients using a MAD for their OSA based upon CPC analysis. Low-frequency coupling decreased as AHI improved, while high-frequency coupling increased as AHI improved. The CPC parameters showed that the sleep quality was improved by MAD therapy.

A histomorphometric study on collagen-apatite composite as a graft material: the influence of gap size at the titanium–bone interface in animal model

The purpose of this study was to evaluate the healing process of collagen-apatite composite (CAC) at the titanium–bone interface in animal model. Small gaps (0.5 or 1.0xa0mm-sized wells) were prepared in the epoxy-resin block implants coated with pure titanium. The gaps were filled with CAC or demineralized freeze-dried bone (DFDB). The titanium-coated epoxy-resin block implants were inserted in the tibia of rabbit for 4xa0weeks or 8xa0weeks. The microscopic features of bony healing process in the grafted gaps were examined and analyzed. In the histomorphometric analysis, CAC group showed higher fraction of newly-formed bone than DFDB group in both 0.5 and 1.0xa0mm gap subgroup at 4-week specimen (Pxa0<xa00.05). In the transmission electron microscopic examinations, osteoblasts of the newly-formed bone of CAC group showed more cellular activity than that of DFDB group. From the results, it was expected that CAC had more beneficial property on early bony healing process than DFDB at the titanium–bone interface.