The effect of occlusogingival placement of clinical bracket points on the adaptation of a straight wire to the lingual arch form / 대한치과교정학회지

OBJECTIVE: The aim of this study is to compare the adaptation of a straight wire between brackets positioned at the mid-lingual surface and those placed gingivally by using a three-dimensional simulation software. METHODS: This cross-sectional study was performed using OrthoAid, an in-house software. The subjects were 36 adolescents with normal Class I occlusion. For each dental cast, two bracket positioning approaches, namely the middle and gingival, were examined. In the middle group, the reference points were placed on the mid-lingual surface of each tooth, while in the gingival group, the reference points were positioned lingually on the anterior teeth. A 4th degree polynomial was adopted, and the in-plane and off-plane root mean squares (RMSs) of the distances between the reference points and the fitted polynomial curve were calculated using the software. Statistical analysis was performed using the paired-samples t-test (α = 0.05). RESULTS: The mean in-plane RMS of the polynomial curve to the bracket distance in the gingival group was significantly lower than that in the middle group (p < 0.001). The off-plane RMS was higher in the gingivally positioned brackets in the maxilla than in the middle group (p < 0.001). However, the off-plane RMS in mandible was not statistically significantly different between the two groups (p = 0.274). CONCLUSIONS: The results demonstrated that the gingival placement of lingual brackets on the anterior teeth could decrease the distance between a tooth and the straight wire.

Craniomaxillofacial bone engineering by scaffolds loaded with stem cells: a systematic review

The concept of tissue engineering holds huge promise for the future treatment of osseous defects. For bone tissue engineering, stem cells are applied on supporting scaffolds under controlled stimulation with growth factors. Scaffolds are provisional matrices for bone growth providing a specific environment for tissue development and favoring cellular attachment, growth and differentiation. To date, ceramics, polymers, and composite scaffolds have been widely used for bone tissue engineering in various in-vitro and animal studies. The objective of this article was to review the advances in jaw bone engineering from a scaffold material point of view. A review of literature was carried out by using Medline database and searching topics like "craniomaxillofacial tissue engineering", "bone regeneration", "scaffold", "oral surgery", "stem cell+ scaffold", "xenograft" and "allograft". Animal and human studies evaluating repair of craniomaxillofacial defects with scaffold and stem cells, were considered in this study. A total of 64 studies were evaluated. Based on the results of this literature review, although autogenous bone grafting has remained the preferred strategy for treatment of bone defects, rapid prototyping [RP] techniques do offer great opportunities to generate suitable scaffolds for bone tissue engineering in near future