Objective:To investigate changes in the circum-maxillary sutures during alternate maxillary expansions and constrictions in a rat model.Methods:Twenty-two male Sprague-Dawley rats (6 weeks old)were used and divided into three groups.In maxillary expansion (ME)group (n=9),an expander was activated for 5 d,and then sacrificed.In alternate maxillary expansions and constrictions (Alt-MEC) group (9 animals),an alternate expansion and constriction protocol (5 d expansion and 5 d constriction for one cycle)was conducted for 2.5 cycles (25 d total),and then sacrificed.The control group com-prised 4 animals with no appliances used,each of two sacrificed on day 5 and day 25 ,respectively.Cir-cum-maxillary sutures (mid-palatal,maxillopalatine,premaxillary,zygomaticotemporal,and frontonasal suture)in each group were characterized histologically.Results:Histological findings of circum-maxil-lary sutures:in control group,the normal sutures were divided into 5 zones,the center was polygon mesenchyme zone,the lateral was mature chondrocyte zone,the next lateral was bone tissue.In ME group,the mid-palatal suture was expanded after ME,the fibre and connective tissue were extracted and invaded into cartilage zone.Osteoblast hyperplasia and new bone formation occurred.The orientation of the new bone trabecula was consistent with force.The osteoclast appeared in some area.Findings of other sutures were similar with those of control group,osteogenesis was active in some area without obvious re-construction in Alt-MEC group,mid-palatal suture and other sutures in some area were widened after Alt-MEC with much more osteoblast hyperplasia and new bone formation.Fibre and connective tissue were extracted,distorted or even broken.Sutures in some areas were narrowed with osteoblast cytopenia and osteoclast hyperplasia.Fibre and connective tissue compressed because of the different force and orienta-tion.Osteoclast count results showed that compared with the control group,the number of the osteoclast was increased only in the palatal suture in ME group (P<0.05 ).Other sutures did not show obvious changes (P>0.05).In Alt-MEC group,the numbers of the osteoclast in circum-maxillary sutures were the most,and had statistical significances (P<0.05 ).Conclusion:These results suggested that cir-cum-maxillary sutures were actively reconstructed after Alt-MEC.while only midpalatal suture had active reaction after ME.

OBJECTIVETo study the boundary between orthodontic and surgical treatment in correction of anterior open bite.

METHODS70 cases (18.0 ages in average) treated orthodontically and 14 cases (25.1 ages in average) treated surgically were chosen. 154 hard and soft tissue measurements were analyzed by statistical software.

RESULTSA diagnostic index, L1MP, was gained with simple factorial analysis. L1MP

CONCLUSIONThe diagnostic index and discriminate function were both useful in determining which method to be chosen in treatment of anterior open bite. The discriminate function was tested to be more efficient than the diagnostic index.

Adolescent ; Adult ; Child ; Humans ; Malocclusion ; diagnosis ; therapy ; Orthodontics, Corrective ; methods

The present study was conducted to examine the morphometrics and function of the disk on both sides among patients with facial asymmetry (FA) and to elucidate plausible correlations between internal derangement (ID) and FA. The sample was composed of 10 males and 27 females with FA. The disk status of all subjects was evaluated by bilateral high resolution magnetic resonance scans in the sagittal (closed and open) and coronal (closed) planes. Five types of disk displacement were identified accordingly. The disk function was diagnosed as normal disk function, disk displacement with reduction, and disk displacement without reduction. The disk shape on sagittal MRI in closed position was classified as bi-concave, biplanar, funnel/hemiconvex, and deformed. The disk position, translation and rotation were also measured. The difference between the shifted side and non-shifted side was analyzed by statistical analysis. Approximately 70% of the patients in the present study showed unilateral or bilateral ID. It was found that anterior disk displacements (ADD), especially rotational ADD, occurred more frequently in the shifted side, while normal disk position was observed mainly in the non-shifted side (p < 0.01). The disk of the shifted side showed significantly deformed configuration and inferior-anterior disk position. However, the disk of the non-deviated side showed hyper-mobility during jaw opening movement. These results demonstrate that in FA patients, the disks status of the shifted side is different from that of the non-shifted side, a phenomenon that could be correlated to facial asymmetry.
Facial Asymmetry ; Female ; Humans ; Jaw ; Magnetic Resonance Imaging* ; Male ; Temporomandibular Joint Disc* ; Temporomandibular Joint*

Objective: To evaluate and compare a series of volume changes in the nasal cavity (NC), nasopharynx, oropharynx, and maxillary sinuses (MS) in growing Class III patients after either rapid palatal expansion (RPE) or alternate rapid maxillary expansion and constriction (Alt-RAMEC) followed by facemask (FM) therapy, by using conebeam computed tomography (CBCT). Methods: Forty growing Class III patients were retrospectively selected and divided into two matched groups: RPE/FM (14 females, 6 males; mean age, 9.66 ± 1.23 years) and Alt-RAMEC/FM groups (14 females, 6 males; mean age, 10.28 ± 1.45 years). The anteroposterior and vertical displacements of Point A, the volumes of the NC, nasopharyngeal, oropharyngeal, and MS were measured at different time points: pretreatment (T1), postexpansion (T2), and postprotraction (T3). Results: Both groups demonstrated significant maxilla advancement (by 1.3 mm) during expansion, with a statistically significant intergroup difference during protraction (RPE/FM, 1.1 mm; Alt-RAMEC/FM, 2.4 mm; p < 0.05) and throughout the treatment (RPE/FM, 2.4 mm; Alt-RAMEC/FM, 3.7 mm; p < 0.05). NC and nasopharyngeal airway volumes increased significantly in both groups after expansion, protraction, and treatment. The oropharyngeal and MS volumes increased in both groups after protraction and post-treatment. However, no volumetric differences were observed between the two groups. Conclusions There was no significant difference in airway volume changes, including NC, nasopharyngeal, oropharyngeal airway, and MS, between RPE/FM and Alt-RAMEC/FM groups at different time points. Although there was significantly more forward movement after protraction in the Alt-RAMEC/FM group, the difference was deemed too small to be clinically relevant.

Purpose: Lateral cephalograms of orthodontic patients may contain incidental findings that could potentially lead to harm. Materials and Methods: The lateral cephalograms of 1765 consecutive 12- to 20-year-old patients, being considered for routine orthodontic treatment, were retrospectively reviewed. These patients were considered normal, because no abnormalities were found either in their medical history or on their clinical examination. Results: The overall prevalence of incidental findings was 18.8%, of which 10.3% were ponticulus posticus and 4.2% were bridging of the sella turcica. Although occipital spurs and ponticulus posticus were more prevalent in males, the size of the sella turcicas did not differ between sexes. Of the 1156 patients completing treatment about 2 years later, only one lateral cephalogram displayed progression of the ponticulus posticus in that time. Conclusion The prevalence of incidental findings on lateral cephalograms of otherwise normal orthodontic 12-to 20-year-old patients was almost a fifth, of which ponticulus posticus, vertebral fusion, and enlarged parietal foramina were clinically significant.