Geometric morphometric analysis of the palatal morphology in children with impacted incisors: A three-dimensional evaluation

Objective:To analyze variations in palatal morphology in subjects presenting unilaterally impacted maxillary permanent central incisors compared with a control group of subjects without eruption anomalies using a three-dimensional (3D) analysis.Materials and Methods:Twenty-six white subjects (10 girls and 16 boys; mean age 9.5 ± 1.5 years) with unilaterally impacted maxillary permanent central incisors (impacted incisor group [IIG]) were compared with a control group (CG) of 26 subjects (14 girls and 12 boys, mean age 8.7 ± 1.6 years) presenting no eruption disorders. For each subject, dental casts were taken and the upper arch was scanned using a 3D laser scanner. To study the entirety of the shape of the palate in any point of the surface, 3D geometric morphometrics was applied.Results:Subjects with impacted maxillary incisors showed skeletal adaptations of the maxilla. In the IIG, both the superior palatal region and lateral palatal surface showed significantly different morphology when compared with CG, with a narrower and higher palatal vault.Conclusion:The absence of maxillary central incisors over the physiological age of eruption influenced the development of the palatal morphology compared with subjects without eruption anomalies.     

Changes of Hyoid,Tongue and Pharyngeal Airway after Mandibular Setback Surgery by Intraoral Vertical Ramus Osteotomy

Objective:To assess changes in hyoid, tongue, pharyngeal airway, and head posture in patients who had mandibular setback surgery by intraoral vertical ramus osteotomy (IVRO) and to investigate the influence of LeFort I osteotomy.Materials and Methods:Sixty patients with skeletal Class III malocclusion were evaluated. All patients had mandibular setback surgery via IVRO, and 45 patients had additional maxillary impaction surgery via LeFort I osteotomy. Lateral cephalograms were taken before, immediately after, approximately 1 month after, and at least 1 year after surgery. Parameters indicating the hyoid, tongue, pharyngeal airway, and head posture were evaluated.Results:The hyoid significantly moved inferoposteriorly immediately after surgery and relapsed superoanteriorly during observation periods. The tongue significantly moved posteriorly during all periods. The final position of the hyoid and tongue was significantly posterior, and the final pharyngeal airway was significantly narrower compared with its presurgical position. Significant cervical hyperflection occurred during observation periods and was strongly correlated with anterior movement of the hyoid. The hyoid and tongue showed similar positions regardless of the presence of different genders or LeFort I osteotomy after the long-term observation period.Conclusions:The hyoid and tongue moved posteriorly after mandibular setback surgery via IVRO, and there was a tendency to relapse back to its original position. However, the final pharyngeal airway width remained narrower after the long-term observation period. Based on our results, careful monitoring of the airway may be needed after mandibular setback surgery via IVRO.     

Three-dimensional analyses of palatal morphology and its relation to upper airway area in obstructive sleep apnea

Objective:To evaluate the relationship between palatal morphology and pharyngeal airway morphology in patients who have obstructive sleep apnea (OSA) and compare with a nonsnoring and nonapneic control group.Materials and Methods:Three-dimensional maxillary dental cast measurements from 25 OSA patients (6 women, 19 men) with a mean age of 41.5 (4.8) years, and 25 control group participants (14 women, 11 men) without any symptom of OSA with a mean age of 38.3 (3.7) were correlated with an analysis of pharyngeal area evaluated with lateral cephalograms. Intermolar and intercanine widths and palatal volumes were calculated on the dental casts, and the upper airway area measurements were performed on lateral cephalograms.Results:OSA patients had smaller oropharyngeal volume and upper airway when compared with controls (P < .001). Palatal area measurements were significantly smaller in OSA (P < .001). OSA patients had significantly narrower maxilla with smaller intermolar and intercanine widths (P < .001). A positive correlation was found between the palatal morphology and pharyngeal dimensions.Conclusions:A significant correlation exists between palatal morphology and pharyngeal airway.     

扩弓辅弓与改良横腭杆扩大上颌牙弓的临床效果比较

目的比较扩弓辅弓和改良横腭杆扩大上颌牙弓的效果。方法分别应用扩弓辅弓与改良横腭杆对35例患者上颌牙弓进行扩弓,比较2组矫治前后的牙弓宽度改变。结果使用扩弓辅弓的病例第一前磨牙扩弓宽度变化不明显,增加2 mm左右,第二前磨牙和第一磨牙的磨牙宽度均有明显扩大,增加4 mm左右;使用改良横腭杆的病例第一、二前磨牙及第一磨牙间宽度均增加4 mm左右。结论上颌牙弓轻中度狭窄的病例采用扩弓辅弓和改良横腭杆扩弓均有较好的扩弓效果,可以根据各自的特点选择合适的病例。     

Dentition in children with enlarged tonsils compared to control children

The aim of the present study was to evaluate whether or not there are any differences in the dentition between children with enlarged tonsils and those with normal tonsils. A sample of 73 children (33 boys and 40 girls) with enlarged tonsils and with a mean age of 10.1 years was compared with a normal control group, matched for age and sex. Eighteen dentition variables and thirty-two variables in anamnestic, clinical, pharyngeal and postural findings were recorded. Measurements were obtained from lateral skull radiographs and dental casts. Group means were compared. Relationships between variables were studied using simple correlations and multiple stepwise regression analyses. It was found that children with enlarged tonsils had more retroclined lower incisors, more anteriorly positioned upper incisors, smaller overbite, larger overjet, shorter lower dental arches, narrower upper dental arches and an increased frequency of lateral crossbite. Functional and/or morphological disorders, causing an open posture of the mouth, a lowered anterior posture of the tongue and a low position of the hyoid bone are thought to be associated with the differences in the dentition between the two groups. Obstruction of the oropharynx by enlarged tonsils, might be one factor responsible for these dysfunctions.     

Longitudinal clinical study on the effect of slow maxillary expansion with removable appliances

The aim of this clinical study was to evaluate the longitudinal changes in dental arches in patients treated with a slow maxillary expansion appliance in primary dentition or early mixed dentitionMethodsThe sample consisted of 19 children (13 girls and 6 boys) with a narrowing of the maxillary arch. The mean ages at the start, at the end of expansion, and at the final follow-up (1 year 7 months after the retention) were 7 years 10 months, 8 years 10 months and 12 years 4 months, respectively. The mean expansion period was 1 year and the mean retention period after the expansion was 1 year 11 months. The control group consisted of 28 Japanese persons with untreated normal occlusion.ResultsThe results were as follows. (1) At the end of the expansion, the maxillary dental arch width increased remarkably, and there was no significant difference in comparison with the control group. (2) At the follow-up after the retention, although the maxillary intercanine width was significantly smaller than the control group, the maxillary intermolar width stabilized during retention and there was no significant difference in comparison with the control group. (3) The mandibular intermolar width gradually increased during the maxillary expansion.ConclusionThis clinical study demonstrated that this type of treatment using a slow maxillary expansion appliance in primary dentition or early mixed dentition is effective and stable in the long term for the maxillary molar regions. Furthermore, it was suggested that the lateral development of the mandibular dental arch could be promoted by expanding the maxillary dental arch width.     

替牙期62例上颌尖牙阻生儿童牙弓及腭部形态特征分析

目的:比较上颌尖牙阻生与无阻生儿童牙弓及腭部形态的差异,为上颌尖牙阻生早期识别和干预提供参考.方法:选择8～11岁[平均(9.82±1.04)岁]儿童62例,分为实验组(上颌尖牙阻生)和对照组(无上颌尖牙阻生),每组31例.将2组患者石膏模型通过3D激光扫描后转化为数字模型,测量牙弓宽度、牙弓长度、基骨宽度、腭部宽度、...     

Maxillary arch dimensions after palatal surgery at different ages on beagle dogs

Changes of maxillary arch dimensions were studied longitudinally until maturity, after palatal surgery was performed on 37 beagle dogs at different ages. The dogs were divided into three experimental groups, a sham group, and a control group. At the age of 6, 16, or 25 weeks in the experimental groups, we created a soft-tissue cleft in the medial region of the palate, made relaxation incisions, and elevated and closed the mucoperiosteum in the midline, thus leaving two areas of denuded bone adjacent to the dentition. We made dental casts regularly until the age of 37 weeks, and studied maxillary arch dimensions. Surgery performed before or during the transition of teeth did not change maxillary arch dimensions in the deciduous dentition, but after the transition, the increase in arch width in the pre-molar region was reduced. Surgery performed after completion of the permanent dentition did not change maxillary arch dimensions. Delay of palatal surgery until the transition of teeth was completed favored normal development of the maxillary dental arch.     

Palatine ridges and tongue position in Turner syndrome subjects

Females with Turner syndrome (TS), X chromosome monosomy, are characterized with palates that are narrow in width, normal in height and which are commonly associated with the presence of lateral palatine ridges. The aim of the present study was to assess the relationship of tongue position, palatal dimensions, and the presence of the lateral palatine ridges in TS subjects. The study also aimed to evaluate the maternal contribution to the palatal dimensions of their TS daughters. The subjects were 71 TS individuals and their female family members (n = 50). Tongue position was evaluated on lateral cephalograms, the palatal height and width measurements and observation of the presence of lateral palatine ridges on dental casts. Differences in tongue position and the palatal index were assessed by an independent sample's t-test, and the relationship between the presence of lateral palatine ridges, tongue position, and palatal dimensions by one-way analysis of variance (ANOVA) and Bonferroni post hoc multiple comparison test. Partial correlation analysis was used to determine the association of palatal dimensions between TS daughters and their mothers. The distance of the tongue from the palate was significantly longer in the TS subjects compared with the controls [10.9 mm (standard deviation, SD, 4.0) versus 7.6 mm (SD 3.4), respectively, P < 0.001] indicating a low tongue position in TS. The TS subjects with prominent lateral palatine ridges had significantly narrower posterior palates compared with the TS subjects without lateral palatine ridges [29.5 mm (SD 3.1) versus 31.5 mm (SD 2.2), respectively, P < 0.05]. There was a trend for an association between mothers and their TS daughters in palatal width measurements at the level of the upper first premolars (r = 0.78, P = 0.07). The tongue position in TS females is low. The presence of prominent lateral palatine ridges is associated with a reduced palatal width.     

Effects of lower primary canine extraction on the mandibular dentition

It has been reported that extraction of primary canines causes a slight mesial drift of the buccal segments, lingual positioning of the incisors, a decrease in arch length, deepening of the bite, and a slight overall crowding in the arch. The aim of this study was to investigate the effects of early mandibular primary canine extraction on permanent incisor and first molar positions, dental and alveolar arch widths, and arch length. Thirty-two patients in the early mixed dentition stage were evaluated. The treatment group (TG) included 16 patients (11 girls, five boys) who had more than 1.6 mm of crowding. Mandibular primary canines were extracted bilaterally in these patients. Another 16 patients (11 girls, five boys) who had less than 1.6 mm of crowding served as controls (CG). Mandibular dental casts and lateral cephalograms of the patients were obtained at the start (T0) and at the recall (T1) period of the trial. At the end of the one-year observation period after removal of lower primary canines, the lower incisors retruded more in the TG as compared with the CG. However, changes in arch length, arch width, and alveolar width were similar between the groups.     

Importance of anatomy in dental implant surgery

BackgroundThe knowledge of nerves and vessels in the maxillofacial region, particularly the anatomical structures in the maxilla, mandible, tongue muscles, and salivary glands, is essential for dental surgeons. In addition, the structures in the mandibular canal, palate, and maxillary sinus should be understood well.HighlightThe arteries and nerves in the maxillofacial region were observed in this study. Some variations in the origin of the inferior alveolar artery were found. Notably, the variations in the origin of the inferior alveolar artery from that of the external carotid artery and a double origin of the inferior alveolar artery were observed. Thus, the maxillary artery may originate from the external carotid and stapedial arteries. The following points are important. (1)The greater palatine artery is always located deeper than the greater palatine nerve. (2)The posterior superior alveolar artery often runs through the compact bone of the maxilla. Using CT scans, the canal of the artery can be observed. (3)Variations in origins of the inferior alveolar artery have been observed. The origin of the inferior alveolar nerve may differ depending on the course of the maxillary artery.ConclusionsDental practitioners should, therefore, have a comprehensive knowledge of the anatomy of the maxillofacial region and its variations. Without this knowledge, they should not operate on patients.     

改良式Hyrax扩弓器矫治上颌牙弓狭窄的临床观察

目的观察改良式Hyrax扩弓器对生长发育期上颌牙弓狭窄的矫治作用。方法选择14例恒牙早期上颌牙弓狭窄病例,应用改良式Hyrax扩弓器进行扩弓。通过测量扩弓前后X线头颅定位侧位片和模型,进行统计学分析。结果14例上颌牙弓狭窄患者经2~3周扩弓后,后牙反全部解除并过矫治2~3mm,■间出现间隙2~4mm。上颌正中咬合片显示:腭中缝打开,低密度阴影出现。结论改良式Hyrax扩弓器是一种快速、有效、安全、经济实惠的扩弓装置。     

Morphology of the palatal vault of primary dentition in transverse view

The purpose of this study was to investigate the transverse view of the morphology of the palatal vault in the primary dentition at the primary second molar level. Observations were obtained from 150 dental stone casts of normal children (78 boys and 72 girls; aged four to five years). Palatal width, palatal depth, arch width, and primary second molar angulation were measured. There were no significant differences in palatal depth and primary second molar angulation between boys and girls or between the right and left sides. However, girls had a statistically significantly narrower upper dental arch width and palatal width than did boys. Palatal widths on the left side were statistically significantly larger than those on the right side for both sexes. Asymmetry in the palatal width greater than two mm was present in 21.8% of boys and 16.7% of girls. There was a correlation between buccal tipping in the upper primary second molar and greater palatal width.     

Dental arches in six-year-old children with operated and unoperated submucous cleft palate and isolated cleft palate

The sizes of dental arches in 129 children with cleft palate were evaluated retrospectively from dental casts taken at the mean age 6.2 years (range 5.2-7.5). The material included 61 children with submucous cleft palate (SMCP) and 68 children with isolated cleft palate (ICP). Twenty of the children with SMCP were not operated on, while 41 had had surgical treatment, either palatal repair (n = 16, mean age at operation: 1.6 years, range 0.8-3.9) or pharyngeal flap (VPP) surgery (n = 25, mean age at operation: 4.5 years, range 2.6-6.2). In children with ICP, one-stage hard-palate and soft-palate closure had been done at the mean age of 1.5 years (range 1.0-2.1). Decreased maxillary intermolar widths were seen in children with SMCP after VPP, and especially after palatal repair. The children with ICP had the smallest maxillary dental arch widths. No significant differences were observed in the maxillary arch length or mandibular intermolar arch dimensions in children with SMCP or ICP. Surgery is associated with decreased maxillary intermolar arch widths in children with SMCP. Children with ICP had smaller maxillary dental arch widths than children SMCP.     

Hyrax快速与慢速扩弓矫治替牙晚期上颌狭窄疗效对比研究

目的 比较Hyrax快速与慢速扩弓矫治替牙晚期上颌狭窄的疗效。 方法 选取2011年1月至2012年12月来大连市口腔医院正畸科就诊的替牙晚期上颌基骨狭窄患者60例,随机分成2组,分别采用Hyrax快速扩弓与Hyrax慢速扩弓进行矫治,扩弓前后拍摄锥形束CT（cone beam computerized tomography ,CBCT）,通过Invivo5牙科软件三维重建,分别测量扩弓前后上颌第一磨牙、第一前磨牙冠状位硬腭水平基骨宽度、颊侧牙弓宽度、双侧牙槽骨倾斜角度的交角、双侧牙齿倾斜角度的交角,轴位颊、舌侧骨质厚度。扩弓前后数据采用SPSS 17.0统计软件进行分析。结果 冠状位：Hyrax快速扩弓与Hyrax慢速扩弓在骨性开展和牙弓总宽度变化上无差别,扩弓后牙弓总宽度增加,第一前磨牙平面的骨开展量大于第一磨牙平面,牙齿和牙槽嵴颊向倾斜,牙槽嵴倾斜的角度慢速扩弓组大于快速扩弓组,牙齿倾斜的角度快速扩弓组大于慢速扩弓组;轴位：颊侧骨质厚度减少,舌侧骨质厚度增加,但Hyrax慢速扩弓组颊侧的减少量小于Hyrax快速扩弓组,两组差异有统计学意义（P＜0.05）。结论 对于替牙晚期患者,与Hyrax快速扩弓相比,Hyrax慢速扩弓慢速轻力的特点更符合生理特性,并且对颊侧的骨质厚度影响小,是一种有效的扩弓方式。     

Quantitative effects of a nickel-titanium palatal expander on skeletal and dental structures in the primary and mixed dentition: a preliminary study

The present study analysed the six-month effects of a nickel-titanium (NiTi) palatal expander on the dental and palatal structures of four primary (mean age 5.8 years) and nine mixed dentition children (mean age 8.7 years), with a posterior unilateral crossbite. Standardized dental and palatal landmarks were digitized using a three-dimensional (3D) electromagnetic instrument. Collected data were analysed with geometric-mathematical models. During a six-month interval, the natural growth and development of the dental arches and hard tissue palate was negligible, as assessed in seven control children (two in the primary dentition, mean age 4.4 years; five in the mixed dentition, mean age 7.7 years). In all children the crossbite was completely corrected. Indeed, dental expansion was always more than or corresponded to the palatal expansion. A smoothing of the size-independent (shape) palatal curvature in the transverse plane was observed. No differences in maximum palatal height were noted. Symmetrical derotation of the anchorage teeth in a distal direction occurred in almost all children. The inclination of the facial axis of the clinical crown (FACC) in the anatomical transverse plane of those teeth with differences between dental and palatal expansion always showed significant modifications (vestibular inclination up to 16.7 degrees). The clinical crown height of anchorage teeth remained nearly the same in all patients. No significant modifications in mandibular arch size were observed. The increase in maxillary arch width, especially in younger children, was probably due to a combination of different effects: opening of the midpalatal suture, tipping of the alveolar process, and molar tipping.     

Class II treatment by palatal miniscrew-system appliance: A case report

This case shows that using a rapid palatal expander (RPE) and then a pendulum appliance anchored to palatal miniscrews is an option for improving treatment management in a noncompliant patient requiring maxillary expansion and molar distalization in the late mixed dentition. First, an RPE was used to expand the maxillary arch. Then, a modified pendulum appliance was used to distalize the maxillary first permanent molars. Optimal positioning of two palatal miniscrews enabled both appliances to be supported by skeletal anchorage. Treatment was finished using multibracket fixed appliances, and after 2 years, skeletal Class I as well as dental Class I canine and molar relationships were achieved.     

A case of anterior open bite with severely narrowed maxillary dental arch and hypertrophic palatine tonsils

Abstract

This case report describes an adolescent patient with an open bite and severely narrowed maxillary dentition and hypertrophic palatine tonsils, treated efficiently with rapid maxillary expansion (RME) and subsequent orthodontic tooth alignment using fixed appliances. The treatment demonstrates that RME can be effective for the correction of a severely narrowed maxillary arch, as well as, in this case, the correction of an anterior open bite in an adolescent patient where no substantial vertical skeletal discrepancy existed.     

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目的 比较Hyrax快速与慢速扩弓矫治替牙晚期上颌狭窄的疗效。方法 选取2011年1月至2012年12月来大连市口腔医院正畸科就诊的替牙晚期上颌基骨狭窄患者60例,随机分成2组,分别采用Hyrax快速扩弓与Hyrax慢速扩弓进行矫治,扩弓前后拍摄锥形束CT(cone beam computerized tomography,CBCT),通过Invivo5牙科软件三维重建,分别测量扩弓前后上颌第一磨牙、第一前磨牙冠状位硬腭水平基骨宽度、颊侧牙弓宽度、双侧牙槽骨倾斜角度的交角、双侧牙齿倾斜角度的交角,轴位颊、舌侧骨质厚度。扩弓前后数据采用SPSS 17.0统计软件进行分析。结果 冠状位:Hyrax快速扩弓与Hyrax慢速扩弓在骨性开展和牙弓总宽度变化上无差别,扩弓后牙弓总宽度增加,第一前磨牙平面的骨开展量大于第一磨牙平面,牙齿和牙槽嵴颊向倾斜,牙槽嵴倾斜的角度慢速扩弓组大于快速扩弓组,牙齿倾斜的角度快速扩弓组大于慢速扩弓组;轴位:颊侧骨质厚度减少,舌侧骨质厚度增加,但Hyrax慢速扩弓组颊侧的减少量小于Hyrax快速扩弓组,两组差异有统计学意义(P<0.05)。结论 对于替牙晚期患者,与Hyrax快速扩弓相比,Hyrax慢速扩弓慢速轻力的特点更符合生理特性,并且对颊侧的骨质厚度影响小,是一种有效的扩弓方式。     

Effects of symmetric and asymmetric rapid maxillary expansion treatments on pharyngeal airway and sinus volume:: A cone-beam computed tomography study

ObjectiveTo evaluate pharyngeal airway and maxillary sinus volumes following symmetric rapid maxillary expansion (RME) and asymmetric rapid maxillary expansion (ARME) treatment using cone-beam computed tomography (CBCT).Materials and MethodsThe study consisted of 60 patients presenting to the orthodontics clinic with an indication that they required symmetric or asymmetric rapid maxillary expansion treatment. Individuals were included if they were aged 12–15 years and had symmetric (RME group; 14 girls, 16 boys) or asymmetric (ARME group; 16 girls, 14 boys) maxillary deficiency. Maxillary sinus volume (mm³) and pharyngeal airway volume (upper, lower, and total; mm³) were evaluated using CBCT records. The parameters were compared before treatment (T1) and after 3 months in retention (T2).ResultsAll measurements at T2 were increased significantly compared with T1 in the RME group (P < .05). In the ARME group, changes in the lower pharyngeal airway and the nonaffected maxillary sinus volumes (non-affected side of maxillary sinus volumes) were not significant; however, the other measurements increased significantly from T1 to T2 (P < .05). Intergroup comparisons revealed that total pharyngeal airway volume and total maxillary sinus volume changes were significantly greater in the RME group.ConclusionsPharyngeal airway and maxillary sinus volumes increased with both RME and ARME treatment. Both were found to be effective for treating transverse maxillary deficiency.