Alveolar bone changes after asymmetric rapid maxillary expansion

Objective:To quantitatively evaluate the effects of asymmetric rapid maxillary expansion (ARME) on cortical bone thickness and buccal alveolar bone height (BABH), and to determine the formation of dehiscence and fenestration in the alveolar bone surrounding the posterior teeth, using cone-beam computed tomography (CBCT).Materials and Methods:The CBCT records of 23 patients with true unilateral posterior skeletal crossbite (10 boys, 14.06 ± 1.08 years old, and 13 girls, 13.64 ± 1.32 years old) who had undergone ARME were selected from our clinic archives. The bonded acrylic ARME appliance, including an occlusal stopper, was used on all patients. CBCT records had been taken before ARME (T1) and after the 3-month retention period (T2). Axial slices of the CBCT images at 3 vertical levels were used to evaluate the buccal and palatal aspects of the canines, first and second premolars, and first molars. Paired samples and independent sample t-tests were used for statistical comparison.Results:The results suggest that buccal cortical bone thickness of the affected side was significantly more affected by the expansion than was the unaffected side (P < .05). ARME significantly reduced the BABH of the canines (P < .01) and the first and second premolars (P < .05) on the affected side. ARME also increased the incidence of dehiscence and fenestration on the affected side.Conclusions:ARME may quantitatively decrease buccal cortical bone thickness and height on the affected side.     

Effects of rapid maxillary expansion on upper airway volume: A three-dimensional cone-beam computed tomography study

Objective:To compare changes in pharyngeal airway volume and minimal cross-sectional area (MCA) between patients undergoing rapid maxillary expansion (RME) and a matched control group and to identify markers for predicting airway changes using cone-beam computed tomography (CBCT).Materials and Methods:Pre- and posttreatment CBCT scans were selected of children who had RME (14 girls and 12 boys; mean age, 12.4 years) along with scans of a control group (matched for chronological age, skeletal age, gender, mandibular inclination) who underwent orthodontic treatment for minor malocclusions without RME. Changes in airway volume and MCA were evaluated using a standardized, previously validated method and analyzed by a mixed-effects linear regression model.Results:Upper airway volume and MCA increased significantly over time for both the RME and matched control groups (P < .01 and P = .05, respectively). Although the RME group showed a greater increase when compared with the matched controls, this difference was not statistically significant. A reduced skeletal age before treatment was a significant marker for a positive effect on the upper airway volume and MCA changes (P < .01).Conclusions:Tooth-borne RME is not associated with a significant change in upper airway volume or MCA in children when compared with controls. The younger the skeletal age before treatment, the more positive the effect on the upper airway changes. The results may prove valuable, especially in RME of young children.     

Comparison of pharyngeal airway volume among different vertical skeletal patterns: A cone-beam computed tomography study

Objective:To test the null hypothesis that there are no significant differences in pharyngeal airway volumes among adult patients with different vertical skeletal patterns and a clinically normal sagittal skeletal pattern using cone-beam computed tomography (CBCT).Material and Methods:The study sample consisted of 100 adult patients (45 men and 55 women; mean age  =  24.0 ± 5.3 years) with a normal sagittal skeletal pattern divided into three groups according to the vertical skeletal patterns: high angle (32 patients: 15 women and 17 men), low angle (34 patients: 14 women and 20 men), and normal angle (34 patients: 16 women and 18 men) groups. Nasopharyngeal, oropharyngeal, and total airway volumes of patients in all vertical groups were calculated. Group differences were analyzed using one-way analysis of variance and post hoc Tukey tests.Results:Nasopharyngeal airway volume in the high-angle group (mean  =  6067.9 ± 1693.9 mm³) was significantly lower than that of the low- and normal-angle groups (P < .01). Oropharyngeal airway volume was highest in the low-angle group (mean  =  15,957.6 ± 6817.2 mm³) and significantly decreased in the control (mean  =  11,826.1 ± 4831.9 mm³; P  =  .008) and high angle (mean  =  10,869.1 ± 4084.1 mm³; P  =  .001) groups. Total airway volume was highest in the low-angle group (mean  =  24,261.6 ± 8470.1 mm³) and lowest in the high-angle group (mean  =  16,937.0 ± 5027.4 mm³; P < .001).Conclusion:The null hypothesis was rejected. Significant differences were found in pharyngeal airway volumes among different skeletal vertical patterns.     

上颌反复快速扩缩前方牵引效果的锥形束CT观察

目的 使用锥形束CT比较上颌单次快速扩弓前方牵引和上颌反复快速扩缩前方牵引的矫治效果,以期为临床提供参考.方法 选择24例上颌后缩患者,使用随机化区组设计的方法分为对照组和反复扩缩组,每组12例.对照组上颌单次快速扩弓后行面罩前方牵引;反复扩缩组上颌反复快速扩缩后行面罩前方牵引.对每组治疗前后的锥形束CT影像进行三维重建、定点、重叠和测量分析.结果 反复扩缩组1例患者在治疗中失访.治疗后反复扩缩组上颌骨前移量[(2.5±1.0)mm]显著大于对照组[(1.6±0.8)mm](P＜0.05);反复扩缩组颅底点至上齿槽座点(Ba-A)的距离增加了(3.1±1.0) mm,显著大于对照组[(2.2±0.9)mm](P＜0.05);反复扩缩组上颌双侧第一磨牙前移量显著大于对照组(P＜0.05).结论 与上颌单次快速扩弓相比,上颌反复快速扩缩前方牵引早期治疗上颌后缩患者可能对上颌骨前移略有利.     

Resolution of maxillary sinus mucositis after endodontic treatment of maxillary teeth with apical periodontitis: a cone-beam computed tomography pilot study

Introduction

Apical periodontitis (AP) is an inflammatory response that can affect the maxillary sinus. This study characterized maxillary sinus mucositis adjacent to teeth with AP and assessed its resolution after endodontic treatment.

Methods

Thirty maxillary sinuses in subjects (n = 29) who had AP associated with maxillary posterior teeth were imaged with cone-beam computed tomography (CBCT). When mucositis was detected, its resolution was assessed with CBCT scanning 3 months after treatment, and periapical healing was assessed using the periapical index (PAI) after 6 months.

Results

Excluding 5 sinuses obscured by sinusitis, mucositis was detected in 14 of 25 sinuses (56%). Nonsignificant inverse association was observed between the mucosal lining thickness and the distance from the sinus to root apices with AP. Four noncompliant subjects were discontinued. Three months after treatment, mucositis was fully resolved in 3 of 10 subjects (30%), partially resolved in 3 of 10 subjects (30%), unchanged in 3 of 10 subjects (30%), and worsened in 1 subject (10%). Six months after treatment, 6 of 10 subjects (60%) had reduced PAI scores classified as healed or healing. The subject with expanded mucositis at 3 months was not healing at 6 months.

Conclusions

Within the limited sample of this pilot study, CBCT imaging revealed a lower-than-expected prevalence of mucositis adjacent to teeth with AP. Fully resolved mucositis was not common 3 months after endodontic treatment, suggesting that in specific cases it might linger beyond 3 months after the elimination of the endodontic infection. Because of the low statistical power, the association between the resolution of mucositis and periapical healing could not be explored.     

锥形束CT分析中国人群上颌后牙区牙槽骨及牙根与上颌窦位置关系的研究

［摘要］ 目的 利用锥形束CT三维成像分析上颌后牙区牙槽骨高度以及牙根与上颌窦底位置关系,为临床诊断和治疗提供可靠的参考依据。方法 选取500例患者的锥形束CT影像资料,测量上颌前磨牙和磨牙的牙槽骨高度、牙根至上颌窦底距离、磨牙牙根与上颌窦的位置关系（垂直和水平关系）,按照牙位和年龄将这些数据分组,分析在不同牙位和年龄段的差异。结果 上颌前磨牙的牙槽骨高度分别为（11.31±7.39）和（9.52±7.98）mm,显著高于上颌磨牙区,随着年龄的增长牙槽骨高度降低。上颌第二磨牙近颊根至上颌窦底距离最短,其平均值为（1.73±3.63）mm;第一前磨牙牙根至上颌窦底的平均值为（9.53±5.79）mm,至上颌窦底距离最长,随着年龄的增长,牙根与上颌窦底间距离变短。在牙根与上颌窦的垂直关系中,三个牙根均不与上颌窦下壁接触的情况显著高于其他分类;水平关系中,在根尖至根分叉水平观察到上颌窦最为常见;随诊年龄的增长牙根与上颌窦的关系更加密切。结论 不同年龄和牙位牙根与上颌窦的关系差异较大,利用锥形束CT可精确分析上颌后牙区解剖结构,制定个性化治疗方案,降低医源性问题的发生。     

口腔种植术前锥形束CT影像评估上颌窦状况

锥形束CT（CBCT）在种植术中具有非常重要的作用,通过CBCT可以了解种植术前术后的情况,判断种植体植入前植入床的基本条件,判断能否进行种植、种植植入方向、方法以及术后评估等。涉及到上颌窦的种植术应常规拍摄CBCT。本文通过临床实例介绍使用CBCT进行种植术前上颌窦分析评估及判断术后可能发生的改变。     

Long-term effects of mini-screw–assisted rapid palatal expansion on airway:: A three-dimensional cone-beam computed tomography study

ObjectivesTo evaluate the long-term effects on airway in patients with mini-screw–assisted rapid palatal expansion (MARPE), rapid palatal expansion (RPE), and controls with three-dimensional cone-beam computed tomography (CBCT) analysis.Materials and MethodsA total of 180 CBCTs of 60 patients were analyzed at different time points, such as pretreatment, postexpansion, and posttreatment. Patients were divided into three groups: mini-screw assisted rapid palatal expansion (MARPE), rapid palatal expansion (RPE), and controls. The nasal cavity, nasopharyngeal, oropharyngeal, and laryngopharyngeal airway volume and area were measured. Changes in total airway volume, total airway area, minimal cross-sectional area, maxillary intermolar width, external maxillary width, and palatal width were also evaluated.ResultsBoth MARPE and RPE caused a statistically significant increase in the airway after expansion as compared with the control group, but there was no statistically significant difference in the change in airway between MARPE, RPE, and the control group at posttreatment, except for nasopharyngeal volume, which was significantly increased in the MARPE group. There was no correlation between the amount of expansion and increase in total airway volume.ConclusionsThere was a significant increase in total airway volume, total airway area, and minimal cross-sectional area with MARPE and RPE immediately after expansion, but at posttreatment, the changes in the MARPE and RPE groups were similar to the change in the control group. However, MARPE led to a significant long-term increase in nasopharyngeal volume. The amount of expansion did not correlate with the increase in pharyngeal airway volume.     

CBCT分析上颌磨牙牙根及其牙槽嵴顶与上颌窦底壁的位置关系

目的 利用CBCT分析上颌第一、第二磨牙各牙根根尖及其牙槽嵴顶与上颌窦底壁位置关系,为临床诊断和治疗提供可靠的参考依据。方法 选取大连医科大学口腔医学院附属口腔医院锥形束CT(CBCT)数据库中初诊180例,分为6～12岁、13～18岁和19～35岁三组,每组各60例。利用CBCT测量上颌第一、第二磨牙各牙根根尖与上颌窦底壁的距离、上颌磨牙牙槽嵴顶与上颌窦底壁距离,分别进行左右两侧与性别差异对比,记录上颌第一、第二磨牙各牙根根尖与上颌窦底壁的位置关系分型,并进行统计学分析。结果 上颌第一磨牙在6～12岁组距离上颌窦底壁平均距离最短的为近颊根(1.21±3.09)mm, 13～18岁组根尖均在上颌窦内,19～35岁组的腭根为(0.41±2.73)mm;上颌第二磨牙在13～18岁组与19～35岁组距离上颌窦底壁平均距离最短的均为近颊根,为(0.36±2.37)mm和(0.43±2.21)mm。随着年龄增长,牙槽嵴顶至上颌窦底壁的平均距离逐渐降低(P<0.05)。水平关系中,上颌第一磨牙13～18岁组、19～35岁组牙根根尖至根分叉区域观察到上颌窦最常见;垂直关系中,6～12岁组与19...     

上颌窦内壁分隔的 CBCT 观测

目的：通过CBCT观测上颌窦内壁间隔的解剖特点及分布规律。方法：调取苏州口腔医院放射科接受CBCT扫描的汉族患者的CT图像资料360例。 Mimics 17．0软件对上颌窦进行三维重建。对上颌窦间隔的发生率、数目、形态、位置及双侧分布状况进行观测。结果：360例中,上颌窦间隔的人群总发生率为37．8％,双侧发生占34．6％,双侧相关系数tau值为0．357（P＜0.01）。分布位置常位于磨牙区。不同性别组、年龄组、牙列缺失缺损及牙列完整组间发生率的差异无统计学意义（P＞0．05）。结论：上颌窦间隔在汉族人具有较高的发生率,了解其解剖特点及分布规律具有重要的临床意义。     

Short-term skeletal and dental changes following bone-borne versus tooth-borne surgically assisted rapid maxillary expansion: A randomized clinical trial study

AimTo evaluate and compare the short-term (post-retention) skeletal and dental changes following bone-borne and tooth-borne surgically assisted rapid maxillary expansion (SARME) using cone beam computed tomography (CBCT).Subjects and methodsIn this randomized clinical study, 30 patients with transverse maxillary deficiency underwent either tooth-borne (n = 15) or bone-borne (n = 15) SARME. Before treatment and immediately after the consolidation period, CBCT was obtained and the nasal floor width, interdental root distance, palatal bone width and interdental cusp distance were measured at first premolar and first molar regions of maxilla.ResultsTwenty eight patients completed the study protocol. In both tooth-borne (n = 13) and bone-borne (n = 15) groups the highest degree of expansion occurred in the dental arch, followed by palatal bone, and nasal floor (V-shaped widening in coronal dimension). The amount and pattern of expansion was comparable between anterior and posterior maxillary regions in each group (parallel posteroanterior expansion) and between the two groups.ConclusionDental and skeletal effects of tooth-borne and bone-borne devices were comparable. The overall complication rate was negligible. Selection of an expansion device should be based on each individual patient's requirements. Future long-term clinical trial studies to evaluate the stability and relapse of these two techniques are recommended.     

Evaluation of opening pattern and bone neoformation at median palatal suture area in patients submitted to surgically assisted rapid maxillary expansion (SARME) through cone beam computed tomography

Surgically assisted rapid maxillary expansion (SARME) is the treatment of choice to adult patients even with severe transversal maxillary discrepancies. However, the adequate retention period to achieve the bone remodeling, thus assuring treatment stability, is controversial.

Objective

To evaluate the opening pattern and bone neoformation process at the midpalatal suture in patients submitted to surgically assisted (SARME) through cone beam computed tomography (CBCT).

Material and Methods

Fourteen patients were submitted to SARME through subtotal Le Fort I osteotomy. Both the opening pattern and the mean bone density at midpalatal suture area to evaluate bone formation were assessed pre- and post-operatively (15, 60 and 180 days) through CBCT.

Results

Type I opening pattern (from anterior to posterior nasal spine) occurred in 12 subjects while type II opening pattern (from anterior nasal spine to transverse palatine suture) occurred in 2 individuals. The 180-day postoperative mean (PO 180) of bone density value was 49.9% of the preoperative mean (Pre) value.

Conclusions

The opening pattern of midpalatal suture is more related to patients’ age (23.9 years in type I and 33.5 years in type II) and surgical technique. It was not possible to observe complete bone formation at midpalatal suture area at the ending of the retention period studied (180 days).     

锥形束CT扫描测量不同矢状骨面型青少年上颌窦大小

目的 利用锥形束CT(CBCT)比较Ⅰ、Ⅱ、Ⅲ类矢状骨面型青少年患者上颌窦大小的差异,探讨上颌窦大小与颅面部骨骼形态的关系.方法 将60例12～16岁的青少年患者按ANB角大小分为Ⅰ、Ⅱ、Ⅲ类三种矢状骨面型组,每组男、女各10例,垂直骨面型皆为均角型.患者接受颅面部CBCT扫描,对上颌窦的长度、宽度、高度、截面积及容积进行测量分析,比较三组间的差异.以CBCT生成的头颅侧位片测量分析颌面部骨骼形态,对上颌窦大小与颌面部骨骼形态的相关性进行研究.结果 不同矢状骨面型青少年患者的上颌窦长度、高度、宽度、截面积和容积的差异具有统计学意义.上颌窦容积Ⅱ类大于Ⅰ类,Ⅱ类大于Ⅲ类.上颌窦容积与前颅底长、全颅底长、ANB角、上中切牙一前鼻嵴点距离及前上面高呈正相关关系,与SNB角呈负相关关系.结论 Ⅱ类骨面型患者具有较大的上颌窦容积,青少年患者上颌窦大小与上下颌骨的矢状关系及颅底长度有一定的相关性.     

手术辅助快速扩弓矫治上颌横向发育不足的临床疗效分析

目的:评价手术辅助快速扩弓矫治成人上颌横向发育不足病例牙齿和基骨的变化。方法:上颌发育不足患者20例(男13例,女7例)按年龄分为扩弓组和手术组,扩弓组(平均年龄12.51±0.82岁)行矫形快速扩弓治疗;手术组(平均年龄19.07±2.54岁)行手术协助快速扩弓治疗。所有患者治疗前后摄头颅定位正侧位片和咬合片,头影测量分析、比较。结果:两组病例均有明显的扩弓效果,手术组牙弓宽度增加更为显著,扩弓组牙弓长度增加明显,但组间均无显著性差异;治疗前后,手术组B点显著后移,而扩弓组B点前移,组间有显著性差异(P<0.05);治疗前后,手术组腭平面后旋,扩弓组腭平面前旋,组间有显著性差异(P<0.01);治疗前后,两组病例上颌切牙均内倾,组间无显著性差异。结论:手术协助快速扩弓治疗成人上颌横向发育不足,可取得良好的扩弓效果;对上下颌骨、上颌切牙在矢状面的改变更有利于III类错畸形的矫正;在病例的选择上,更适用于低角病例。     

A cone-beam computed tomography study of the mesial cervical concavity of maxillary first premolars

ObjectiveTo investigate the mesial cervical concavity of maxillary first premolars and its relationship with root and canal configuration using cone-beam computed tomography (CBCT).DesignImages of maxillary first premolars (n = 1056) were collected from patients (n = 601) who had undergonein vivo CBCT scanning. The root and canal number and morphology were evaluated. The following measurements of the mesial cervical concavity of the maxillary first premolars were evaluated in section images: dentine thickness (in concavity at the cemento-enamel junction), concavity angle, depression depth (distance from mesial dentinal surface at concavity to mesial proximity), concavity position (distance from mesial dentinal wall at invagination to the top of the mesial marginal ridge). The reliability of the data was analyzed with an unpaired Student’s t test and Fisher’s exact test.ResultsThe percentages of maxillary first premolars with one root, two, and three roots were 55.5%, 43.7%, and 0.8% respectively. Mesial cervical concavity was recorded in 64.5% of single-root maxillary premolars. The prevalence of two-root maxillary first premolars with mesial cervical concavity was 73.8%. The means of the aforementioned four measurements were 1.705, 147.9, 1.640, and 5.247 mm. The values of dentine thickness (mm), depression depth (mm), and concavity position (mm) of the mesial cervical concavity were largest in two-root maxillary first premolars. The smallest concavity angle of the mesial cervical concavity was found in three-root maxillary first premolars.ConclusionsThere is a high prevalence of mesial cervical concavity among maxillary first premolars. The mesial root concavity is more prevalent in single-rooted maxillary first premolars when there are two canals present, and its prevalence and degree of concavity increase with the number of roots.     

锥形束CT冠状位分析上颌后牙牙根与上颌窦底垂直向位置关系的初步研究

目的 通过对锥形束CT影像资料的回顾性研究,分析在冠状位上上颌后牙根与上颌窦底的垂直向关系.方法 对162例成年患者锥形束CT的影像资料进行回顾性研究,在冠状位上将根尖与上颌窦底的垂直向位置关系进行分型统计.结果 上颌前磨牙主要是0类关系,上颌磨牙有20％左右根尖突入上颌窦底,磨牙的各个牙根与上颌窦底的关系各不相同.结论 上颌后牙根尖突入上颌窦底的比例不同,以第一磨牙的腭根和第二磨牙的近中颊根比率最高.     

Evaluation of mandibular volume using cone-beam computed tomography and correlation with cephalometric values

Objective:To investigate the association between maxillofacial morphology and mandibular bone volume in patients with skeletal malocclusion.Materials and Methods:Subjects were 118 adult Japanese (58 males and 60 females). Skeletal malocclusion was classified, based on cephalometric analysis, into skeletal Classes I (−1° ≤ ANB < 4°), II (ANB ≥ 4°), and III (ANB < −1°). Using cone-beam computed tomography and three-dimensional image analysis software, the dental crowns and mandible were separated, with only the mandible extracted. This was then reconstructed as a three-dimensional model, from which the mandibular volume was measured.Results:No significant difference in mandibular volume was noted among skeletal Classes I, II, and III, nor was there any significant correlation between mandibular volume and the ANB, SNB, or mandibular plane angles. There was occasional and limited correlation between mandible volume and gonial angle and certain cephalometric distance parameters.Conclusion:We conclude that proper understanding of the three-dimensional maxillofacial morphology requires not only cephalometric radiographic tracings but also high-resolution analysis of the mandibular area, width, and volume.