Labial inverse dilaceration of bilateral maxillary central incisors: A case report

BACKGROUND Dilaceration is a rare dental developmental anomaly characterized by an abrupt deviation along the longitudinal axis of the root in which an angulation forms between the root and the crown.Here,we report on dilacerated bilateral maxi-llary central incisors in mixed dentition.CASE SUMMARY A 10-year-old girl presented with a chief complaint of unerupted central incisors.An oral examination and radiography provided the basis for a diagnosis of dilaceration of the maxillary central incisors.After surgical exposure of the impacted teeth,a button with an attached chain was applied to the palatal surface of teeth 11 and 21.After 8 mo,a button was bonded to the labial surface of the crown to fix an elastic chain and move the teeth toward the maxillary arch.Finally,a fixed appliance was applied to tooth alignment to Class 1 malocclusion using a 0.019×0.025-inch nickel-titanium wire.After 3 years of follow-up,the clinical findings and radiographic assessment showed that the roots had developed with vital dental pulp and healthy periodontium,were acceptable aesthetically,and showed no resorption.CONCLUSION The rare occurrences of dilacerated bilateral maxillary central incisors can be successfully treated through surgical exposure and orthodontics.

Clinical Management of Mid-Root Fracture in Maxillary Central Incisors:Case Reports

Management of mid-root fractures presents a formidable challenge for clinicians because of the difficulty of achieving a stable reunion of fracture fragments. This article presents two varied treatment options for mid-root fractures. A 15-year-old female reported an impact injury to the maxillary anterior teeth 2 days after its occurrence. Clinically,the maxillary left central incisor was palatally-extruded with a negative vitality response and radiographic evidence of an oblique fracture at the middle third of the root. An endodontic implant was employed which utilized an open technique and has been on follow-up for ten months. A 32-year-old male reported an injury,which resulted in a mobile maxillary right central incisor,three months after its occurrence. Through clinical and radiographic means,a discolored,extruded,and non-vital maxillary right central incisor with an oblique root fracture at the alveolar-crest level was observed. Exploratory surgery was performed; an apical barrier was created with a mineral trioxide aggregate and obturated with gutta percha. The fragments were stabilized with a fiber post and patient has been on follow-up for five months. Short-term follow-up for both of the cases showed promising results both clinically and radiographically.

Average Odontometric Value of the Width of the Upper Central Incisor in the Congolese Bantu of Kinshasa, Democratic Republic of Congo

Objective: The aim of this study was to determine the average values of width of the upper central incisor (WUCI) in Congolese Bantu and compare them to those of Caucasians and Asiatic. Material and Methods: It was a prospective cross-sectional study carried out at the Université de Kinshasa on the Congolese Bantu, Department of Dental Medicine, from March 2020 to March 2021. A maxillary imprint was taken by Jeltrate-type alginate. The measurement of two healthy upper central incisors (UCI) was carried out by the hard plaster casting type 4, with a brand caliper, carbon fiver composite mark. The study was approved by the Ethics Committee of the School of Public Health in the Université de Kinshasa and verbal consent was obtained from each participant. Results: The Average Width of the UCI was 8.74 mm ± 0.56. The average width of the right Upper Central incisor (RUCI) and the left UCI (LUCI) was 8.71 mm ± 0.57 and 8.77 mm ± 0.56, respectively. The average width of the RUCI and LUCI was not the same for men and women (p 0.001). A significant difference was observed between the average of the RUCI and the 18 - 28 and 40 - 50 age group (p = 0.056) as well as for the average LUCI (p = 0.085). The width average of UCI between the Congolese Bantu with those of Caucasians and Asians was significantly different (p = 0.000 and p = 0.009). Conclusion: The average width of the RUCI and LUCI was different among sex and age group. The average width of UCI of the Congolese Bantu is different from that of Caucasians and Asians.

Determinants Factors for the Choice of the Width Prosthetic Upper Central Incisor: Review of the Literature

Materials and Methods: The authors conducted a review of the literature around the theme, determinants of the choice of the width of the upper central incisor (WUCI), through search web including Pub Med, Inari and Google. Fifteen of the most recent publications since 2005 have been selected from twenty publications. Sample size (n), age range (AR), average bi zygomatic distance (BZD), choice determinants, type of study, and mathematical formula between WUCI and BZD were the study’s interest variables. Sociodemographic characteristics, facial anatomical marks and the size of the patient’s teeth for anterosuperior were the main factors to be assessed. Results: Out of 22 included articles, the Asian continent represents 59% in which India is the leading country with 27.3% followed by American 22.8%. The most Determinants choice for the width upper central incisor in craniofacial and anterior teeth method from the published papers were BZD (100%;n = 22) and WUCI (81.8%;n = 18). Conclusion: Application of mathematical formulation maybe help to predict the exact width of the upper central incisor.

Opinions of traditional birth attendants in Ibadan, Nigeria, towards reversal of eruption sequence of primary central incisors in infants

Introduction: Traditional birth attendants (TBA’s) have been a good medium for transferring health education messages in culturally acceptable ways. It is believed that they will be a good asset to demystify the misconceptions associated with reversal of eruption sequence in the community. Aim: To assess the opinions of TBA’s towards reversal of eruption sequence of primary central incisors in infants. Methods: A cross sectional study was conducted among all consenting TBA’s in the five urban local government areas in Ibadan, using a pretested 17-item semi structured interviewer administered questionnaire. Results: Forty eight (29.4%) respondents will be astonished at seeing children erupting upper primary central incisors before the lowers, while 25 (15.3%) will regard them as strange. Thirty five (21.1%) respondents felt this condition was due to evil spirits while 13 (8.0%) believed that child’s parents had breached traditional taboos. There was a correlation between negative beliefs about this variation and age (p = 0.038) and education (p = 0.020). Their opinion on the families of the affected children was hideous as (13.5%), (23.3%) and (27.6%) regarded it as a curse, embarrassment and abomination respectively and this was associated with their educational status (p = 0.014). Many (61.3%) of the respondents would advise the parents to hide or get rid of such children whilst (33.7%) advocated for extraction and only 8 (4.9%) felt child and the tooth should be left alone. Conclusion: Many of the TBA’s have dissenting mind-sets towards such children and their families. The practices of many of the TBA’s towards such teeth are disturbing and necessitate urgent intervention. The risks are that wrong advice may be given to such parents by the TBA’s and affected children may be deserted, abandoned, stigmatized and exposed to hazards. Older and less educated TBA’s have a greater tendency to believe these misconceptions.

Contour changes in human alveolar bone following tooth extraction of the maxillary central incisor

The purpose of this study was to apply cone-beam computed tomography （CBCT） to observe contour changes in human alveolar bone after tooth extraction of the maxillary central incisor and to provide original mor- phological evidence for aesthetic implant treatment in the maxillary anterior area. Forty patients were recruited into the study. Each patient had two CBCT scans （CBCT I and CBCT II）, one taken before and one taken three months after tooth extraction of maxillary central incisor （test tooth T）. A fixed anatomic reference point was used to orient the starting axial slice of the two scans. On three CBCT I axial slices, which represented the deep, middle, and shallow layers of the socket, labial and palatal alveolar bone widths of T were measured. The number of sagittal slices from the start point to the pulp centre of T was recorded. On three CBCT II axial slices, the pulp centres of extracted T were oriented according to the number of moved sagittal slices recorded in CBCT I. Labial and palatal alveolar bone widths at the oriented sites were measured. On the CBCT I axial slice which represented the middle layer of the socket, sagittal slices were reconstructed. Relevant distances of T on the sagittal slice were measured, as were the alveolar bone width and tooth length of the opposite central incisor. On the CBCT II axial slice, which represented the middle layer of the socket, relevant distances recorded in CBCT I were transferred on the sagittal slice. The height reduction of alveolar bone on labial and palatal sides was measured, as were the alveolar bone width and tooth length of the opposite central incisor at the oriented site. Intraobserver reliability assessed by intraclass correlation coefficients （ICCs） was high. Paired sample t-tests were performed. The alveolar bone width and tooth length of the opposite central incisor showed no statistical differences （P〈0.05）. The labial alveolar bone widths of T at the deep, middle, and shallow layers all showed statistical differences. However, no palatal alveolar bone widths showed any statistical differences. The width reduction of alveolar bone was 1.2, 1.6, and 2.7 mm at the deep, middle, and shallow layers, respectively. The height reduction of alveolar bone on labial and palatal sides of T both showed statistical differences, which was 1.9 and 1.1 mm, respectively.

Morphometric Analysis of Maxillary Central Incisor to Determine its Crown Form: A Model‑based Cross‑sectional Study

The size and shape of tooth crowns are morphogenetically predetermined during embryogenesis.The maxillary central incisors have contributed to sexual dimorphism,and several classifications of the form of maxillary central incisors are available in the literature.We,in the present study,aimed to analyze the mesiodistal(MD)measurements at two levels of maxillary central incisor,to determine its crown form.The study was conducted on 100 dental plaster models(50 males and 50 females).The MD dimensions at the contact area level MD_incisal(MD_I)and at the gingival papilla level(MD_G)and the gingivo‑incisal height of the crown were measured in the dental models using digital Vernier caliper.The data were analyzed using SPSS version 16 statistical software.The mean values of all the three parameters measured were slightly greater for males and also for the left central incisors.There were no significant differences in all the three variables when the right and left incisors were compared.Significant differences were noted when the parameters are compared between genders.The height/width ratio of crown showed a significant difference between male and female.The value of the ratio between the two MD dimensions(MD_I and MD_G)was used to determine the crown form.The ratio between the MD dimensions at incisal and gingival area showed a significant difference between genders and no such significance was found between right and left central incisors.There is a significant difference in the form of maxillary central incisors between male and female samples and not between right and left.The MD dimensions at incisal and gingival thirds decide the form of crown.

Correlation between Maxillary Central Incisor Crown Form and Maxillary Dental Arch Form:A Model‑Based Morphometric,Cross‑Sectional Study

The crown form of maxillary central incisor tooth is one of the vital phenomenon for a person’s esthetics.Its crown form has been compared with other anatomical parameters such as arch form and facial form.Three different classes of tooth forms which relate to square,tapered,and ovoid forms are identified.The aim of this study was to morphometrically evaluate the correlation between maxillary dental arch form and the maxillary central incisor crown form.Dentate cast models of fifty male and fifty female normal occlusion controls in the age group of 18-23 years were analyzed.The mesiodistal(MD)dimensions of the maxillary central incisors were measured at incisal(MD_I)and at gingival(MD_G)levels.The transverse widths of maxillary casts were measured at the first molar and at the first premolar levels.The measured data were statistically analyzed using the SPSS software.The MD dimensions of maxillary central incisor were significantly greater in males than females.The ratio between the two MD dimensions also varied significantly among genders.The intermolar width(IMW)and interfirst premolar width(IPmW)between males and females were highly significant(P<0.05),whereas the ratio between these two parameters in males and females was not significant(P=0.43).Eighty‑eight percentage of the participants were found to have an ovoid type of maxillary arch,while only 45%of them had the ovoid form of maxillary central incisors.The MD_I and the IMW were found to be in the ratio of 1:5.5 in both genders.The MD_G and the IPmW were in the ratio of 1:4.7 in males and 1:4.5 in females.There was a weak positive correlation between MD_I and IMW(r^(2)=0.146)and between MD_G and IPmW(r^(2)=0.05).No significant concordance between the maxillary central incisor crown form and the maxillary arch form was found in this study.

Prediction of Facial Profile Based on Morphometric Measurements and Profile Characteristics of Permanent Maxillary Central Incisor Teeth

The computation of facial profile from dental morphometrics has been a subject of great interest in forensic odontology.The use of teeth to draw a profile and facial features is valuable in times of mass disasters when body remains are unavailable due to extreme destruction.This study aims to identify and evaluate applicable parameters in the permanent maxillary central incisors and the face of an individual.A correlation of these parameters establishes a mathematical equation that further charts a tooth‑facial profile table.Thirty soft and hard tissue landmarks on the face in the frontal and the lateral profiles(using standardized photographs)and seven landmarks on the facial/labial surface of the clinical crown of the permanent maxillary central incisor(using casts of the maxilla)were identified for the study.Based on these,a set of eight horizontal and seven vertical parameters on the face and four parameters on the tooth were created for the assessment.Internal and external correlations between the two were carried out and statistically analyzed.A logistic regression was made to predict the probability of the parameters most likely to be reproduced in the creation of the facial profile,based on tooth morphometrics.The results indicated a definite correlation between the facial and the tooth parameters.Among the multiple parameters,a definite correlation in the horizontal dimension could be established between the mouth width and the mesiodistal width(MDW)of the tooth.In the vertical dimension,a definite relationship existed between the crown height of the tooth and the width of the midface(zygoma‑mandible).There exist divergences in the correlation of tooth and facial parameters.

隐形矫治器设计上切牙压低量对牙根吸收的影响分析

目的研究在隐形矫治技术中上颌中切牙的压低量与牙根吸收的关系。方法纳入于合肥市口腔医院正畸一科采用隐形矫治技术治疗深覆牙合的非拔牙患者62例,在正畸治疗前(T0)、压低量1 mm时(T1)和压低量2 mm时(T2)进行三次CBCT追踪检查。测量三个时期上切牙牙根长度、牙根体积和唇腭侧牙槽骨高度,运用SPSS 26.0软件进行统计学分析。结果牙根吸收与压低量呈正相关(P<0.05);压低量越大,切牙唇倾度越大(P<0.05);三个阶段的唇侧牙槽骨高度无统计学差异(P>0.05),腭侧牙槽骨高度的差异有统计学意义(P<0.05),T2期腭侧牙槽骨吸收明显;牙根吸收与治疗时间呈正相关(P<0.05)。结论隐形矫治技术中上颌中切牙牙根吸收与压低量有关。

上颌中切牙牙弓形态、牙槽骨厚度及矢状面位置的锥体束计算机断层扫描研究

目的:利用锥体束计算机断层扫描(cone-beam computed tomography, CBCT)图像评估上颌前牙牙弓形态、中切牙牙根矢状位置(sagittal root position, SRP)与牙槽骨厚度的关系,并根据年龄、性别对其分组,临床医生在即刻种植体植入时应考虑这些因素。方法:对符合纳入标准的160例患者的CBCT影像进行分析,根据牙弓形态、年龄、性别对其分组,对患者的320张上颌中切牙矢状位CBCT图像进行了检查,以测量唇侧骨板和腭侧骨板厚度,进行统计学分析。结果:牙槽骨厚度因牙弓形态和SRP的不同而有显著差异。方圆形牙弓型和Ⅰ类SRP在腭侧的骨厚度最高。尖圆形弓型和Ⅱ类SRP在唇侧骨厚度最高。牙弓形态与SRP之间无显著相关性。年龄、性别、牙弓形态、SRP与牙槽骨的根尖水平厚度有显著相关性。结论:患者的年龄、性别、牙弓形态和SRP与上颌中切牙的牙槽骨厚度有不同程度的相关性。因此,临床医生在计划即刻种植体植入时应考虑这些因素。

倒置埋伏阻生中切牙正畸牵引前后牙根发育的CBCT三维重建分析

目的:使用CBCT三维重建分析,探讨倒置埋伏阻生中切牙正畸牵引前后牙根发育的变化。方法:选择改良活动牵引器联合外科助萌治疗的10例上颌单侧倒置埋伏阻生中切牙患者,使用Mimics 21.0软件对治疗前后埋伏阻生中切牙(埋伏牙组)及对侧同名牙(健侧组)的CBCT数据进行三维重建,并计算牙体积与表面积。采用SPSS 26.0软件包进行配对t检验,比较治疗前后牙根发育情况。结果:10例患者均牵引成功,平均用时(16.10±4.46)个月。治疗后埋伏牙组牙体积与表面积均较治疗前显著增加(P<0.01)。牵引前和牵引后埋伏牙组牙体积与表面积均显著小于健侧组(P<0.01),但治疗过程中,埋伏牙组与健侧组牙体积与表面积的增加量无统计学差异(P>0.05)。结论:改良活动牵引器联合外科助萌可促进上颌倒置埋伏阻生中切牙牙根进一步发育,是一种安全可靠的治疗方法。

切牙管影响上中切牙三维移动的研究进展

上中切牙的位置在面部美学中有十分重要的意义。在正畸治疗过程中,为获得理想的矫正效果,上中切牙会根据实际情况进行三维方向上的移动。以往观点认为上中切牙移动的范围只受到上颌骨唇、腭侧骨皮质的限制,但随着锥形束计算机体层成像(CBCT)的应用,发现在上颌骨内存在着解剖形态不规则的切牙管,其外侧壁由致密的皮质骨围绕而成,若上中切牙与之发生碰撞不仅会导致接触部位的牙根吸收,还可导致骨开窗、骨开裂,引发牙周问题,甚至还可能压迫鼻腭管神经等。因此,上中切牙三维移动的边界与切牙管的形态及位置关系密切,应引起重视,以避免临床工作中对上中切牙的牙根造成不必要伤害。本文就切牙管对上中切牙三维移动的影响做一综述。

微型种植体支抗在错牙合畸形口腔正畸治疗患者中的应用效果

目的:观察微型种植体支抗在错牙合畸形口腔正畸治疗患者中的应用效果。方法:选取2020年7月至2022年7月该院收治的84例错牙合畸形口腔正畸治疗患者进行前瞻性研究,按随机数字表法将其分为对照组与观察组各42例。对照组给予传统支抗治疗,观察组给予微型种植体支抗治疗。比较两组牙齿结构相关指标水平、舒适度评分、临床疗效和不良事件发生率。结果:观察组磨牙位移小于对照组,上中切牙凸距差、上中切牙倾角差均大于对照组,差异有统计学意义(P<0.05);观察组舒适度评分高于对照组,差异有统计学意义(P<0.05);观察组治疗总有效率为95.24%(40/42),高于对照组的76.19%(32/42),差异有统计学意义(P<0.05);两组不良事件发生率比较,差异无统计学意义(P>0.05)。结论:微型种植体支抗应用于错牙合畸形口腔正畸治疗患者可提高治疗总有效率和舒适度评分,改善牙齿结构相关指标水平,其效果优于传统支抗治疗。

上颌中切牙即刻种植术后骨量变化的影响因素探讨

目的 探讨单颗上颌中切牙即刻种植的临床效果及术后种植体周骨量的影响因素。方法 选取接受单颗上颌中切牙即刻种植治疗的100例患者(100枚种植体)为研究对象,收集患者临床资料及术前、术后当天和术后6个月影像学资料。测量术后即刻和术后6个月的种植体唇腭侧颈部、中部和根部的骨板厚度,观察骨量变化的规律,并通过回归分析模型评估唇腭侧骨板厚度的预测因素。结果 术后6个月,种植体颈部、中部和根部唇侧骨厚度分别为2.35、2.29和3.28 mm,腭侧分别为0.00、2.40和6.05 mm;颈部骨吸收率最高,唇侧和腭侧分别为32.87%和62.20%;回归分析模型显示,种植体颈部唇侧骨厚度的影响因素为种植体颈部唇侧初始骨厚度、横断面上种植体中心与两邻牙中心连线夹角、种植体直径和愈合方式(P<0.05),而种植体腭侧初始骨厚度为种植体腭侧骨厚度的唯一预测因素(P<0.05)。结论 单颗上颌中切牙即刻种植临床效果良好,种植体周新生骨厚度受多种因素共同影响,在制定即刻种植方案时,需综合考虑这些因素以达到最佳治疗效果。

华南地区成人上颌中切牙与牙槽骨相对位置关系CBCT分析

目的探究华南地区成人上颌中切牙在牙槽骨中的位置及其骨壁厚度特征,为上颌中切牙即刻种植术前设计提供临床参考。方法获得医院伦理委员会审批及患者知情同意,采集2018年1月至2021年12月,南方医科大学口腔医院就诊的990例华南地区成人健康上颌中切牙患者的口腔锥形束CT(cone beam computer tomography,CBCT)影像,按性别和年龄分组。从CBCT影像中,确定适宜矢状面和标志点,分析牙根在牙槽骨位置关系,测量釉牙骨质界(cementoenamel junction,CEJ)下4 mm、根中处和根尖处的唇侧及腭侧骨壁厚度,同时测量牙长轴与牙槽骨长轴夹角。比较不同性别组唇腭侧骨壁厚度,比较不同性别组及年龄组(20~39岁;40~59岁;60~79岁)牙齿长轴与牙槽骨长轴夹角关系。结果华南地区成人上颌中切牙矢状面牙根在牙槽骨的唇腭侧位置关系存在显著差异,其中根尖在牙槽骨唇侧1/3处占比为95.8%(948/990),根尖在牙槽骨中1/3处的占比为4.1%(41/990),根尖在牙槽骨腭侧1/3处占比为0.1%(1/990);腭侧CEJ下4 mm、根中、根尖处骨壁厚度为(1.82±0.56)mm、(3.20±1.10)mm、(7.70±2.00)mm,均大于唇侧的(1.21±0.32)mm、(0.89±0.35)mm、(1.86±0.82)mm,差异有统计学意义(P<0.05);男性骨壁厚度普遍大于女性(P<0.05);男性牙与牙槽骨长轴夹角为14.77°±5.66°,女性为12.80°±5.70°,差异有统计学意义(P<0.05);40~59岁组和60~79岁组牙与牙槽骨长轴夹角均大于20~39岁组,差异有统计学意义(P<0.05)。结论95.8%的华南地区成人上颌中切牙的牙根偏向唇侧骨壁,根尖处腭侧骨厚度大于唇侧;所测位点中,根中处唇侧骨壁厚度最小。华南地区成人中男性上中切牙与牙槽骨长轴夹角大于女性,且夹角随年龄增长而增大。上颌中切牙即刻种植术前需关注根周骨壁厚度和牙根与牙槽骨长轴夹角大小,合理选择种植方案。

安氏Ⅱ类2分类合并短根异常症上颌中切牙牙槽骨形态测量

目的:评估安氏Ⅱ类2分类错[牙合]畸形合并短根异常症(SRA)患者的上颌中切牙牙槽骨三维形态学特征,对其正畸治疗和风险防范提供参考依据。方法:选取就诊的安氏Ⅱ类2分类错[牙合]畸形患者112例为研究对象,分为研究组(SRA患者)与对照组(正常牙根患者)各56例。拍摄锥形束CT(CBCT)后测量两组患者左右两侧上颌中切牙牙槽骨厚度和高度、骨开窗和骨开裂发生率并进行统计学分析。结果:研究组唇侧牙槽骨厚度在根中平面、根尖平面均小于对照组;牙槽骨总厚度在根尖平面小于对照组,差异均有统计学意义(P<0.05);研究组唇侧牙槽骨高度大于对照组,差异有统计学意义(P<0.05);研究组唇侧牙槽骨厚度在根尖平面<1 mm占比高于对照组,在根中和根尖平面>2 mm占比均低于对照组,差异有统计学意义(P<0.05);研究组骨开窗和骨开裂的发生率高于对照组,差异有统计学意义(P<0.05)。结论:对于安氏Ⅱ类2分类SRA患者的正畸治疗,应结合其上颌中切牙牙槽骨菲薄、附着高度小、骨缺损发生率高的特点制定个性化的牙移动方案。

植入位点及轴向对上颌中切牙即刻种植即刻负重应力影响的三维有限元分析

目的探讨不同牙槽窝形态上颌中切牙即刻种植即刻负重时,植入位点及轴向对种植体周围骨界面应力分布的影响。方法参照1名健康成年人口腔锥体束计算机断层(cone beam computed tomography,CBCT)影像资料,建立偏唇型、中间型、偏腭型3种牙槽窝形态的上颌中切牙即刻种植即刻负重三维有限元模型;模拟不同植入位点(根尖位点、偏腭/唇侧位点)及轴向(牙长轴、牙槽骨长轴);对已建模型以100 N力进行不同角度(0°、30°、45°、60°、90°)的应力加载;应用ANSYS软件分析种植体周围牙槽骨的应力情况。结果成功建立12个不同牙槽窝形态上颌中切牙即刻种植即刻负重三维有限元模型。偏唇型及中间型牙槽窝形态行即刻种植即刻负重时,沿牙槽骨长轴方向偏腭位点植入种植体更易获得良好的种植体骨界面生物力学特性;偏腭型牙槽窝形态行即刻种植即刻负重时,在偏唇位点植入,不论是沿牙长轴方向还是沿牙槽骨长轴方向植入种植体,种植体周牙槽骨所受等效应力远小于根尖位点植入。结论不同牙槽窝形态、植入位点及轴向都会对上颌中切牙即刻种植即刻负重种植体骨界面生物力学特点产生影响。临床中,应针对不同牙槽窝形态制定不同植入轴向及植入位点的手术方案。

基于HSB色彩模型的右上颌中切牙各区域颜色变化规律的研究

目的基于HSB色彩模型,测量牙齿各区域的色相(H)、饱和度(S)、亮度(B)数值,探寻牙齿各区域颜色变化规律。方法收集65例患者的65颗右上颌中切牙。利用拾色器工具避开反光区对右上颌中切牙的颈部、中部、切缘牙体颜色进行测量,按公式计算总体色彩参数及各区域色彩参数与总体的相对差异。最后,对计算结果进行统计,寻找牙齿各部位颜色变化规律。结果结果显示,在同一颗右上颌中切牙,颈部、中部、切缘的色相、饱和度、亮度较牙齿总体色彩参数均有所区别。在同一颗右上颌中切牙,颈部与中部的色相差异以及中部与切缘的色相差异具有统计学意义;颈部、中部、切缘的饱和度差异均具有统计学意义;颈部与切缘、中部与切缘的亮度差异也具有统计学意义。结论右上颌中切牙各区域的色彩具有差异性。在同一颗右上颌中切牙,中部色相最偏黄,颈部和切缘色相偏红;颈部的饱和度最高,中部次之,切缘饱和度最低;切缘亮度最低。

年轻上颌中切牙根尖区解剖结构的CBCT测量

目的:研究年轻上颌中切牙根尖区解剖结构的CBCT影像学表现。方法:纳入100例Nolla 8期、100例Nolla 9期的正常年轻上颌中切牙CBCT影像资料,观察根尖区骨硬板的影像学特征,应用CBCT自带软件测量根尖孔近远中径及唇舌向径、根尖区阴影近远中径、唇舌向径及上下径,比较Nolla 8期与Nolla 9期根尖孔及根尖区阴影各径线的大小,分析根尖孔与正常根尖区阴影各径线间是否存在相关性。结果:年轻上颌中切牙Nolla 8期根尖孔近远中径、唇舌向径分别为:(2.75±0.68)mm、(3.28±0.74)mm,正常根尖区阴影近远中径、唇舌向径及上下径分别为:(3.84±0.73)mm、(4.49±0.68)mm、(3.41±1.27)mm;年轻上颌中切牙Nolla 9期根尖孔近远中径、唇舌向径分别为:(1.50±0.51)mm、(1.92±0.79)mm,正常根尖区阴影近远中径、唇舌向径及上下径分别为:(2.76±0.60)mm、(3.41±0.80)mm、(2.06±0.65)mm;Nolla 9期根尖孔近远中径及唇舌向径、根尖区阴影近远中径、唇舌向径及上下径较Nolla 8期显著减小(t=14.75,P<0.01;t=12.65,P<0.01;t=11.42,P<0.01;t=10.27,P<0.01;t=9.36,P<0.01);正常根尖区阴影近远中径、唇舌向径及上下径与根尖孔近远中径及唇舌向径呈正相关(根尖孔近远中径:r=0.904,P<0.01;r=0.700,P<0.01;r=0.552,P<0.01。根尖孔唇舌向径:r=0.739,P<0.01;r=0.876,P<0.01;r=0.445,P<0.01)。Nolla 8期上颌中切牙根尖区更可能出现模糊的宽带骨硬板,随着根尖孔的发育,根尖区骨硬板倾向于清晰锐利。结论:Nolla 8期较Nolla 9期上颌中切牙具有更大的根尖孔及根尖区阴影,骨硬板趋于清晰锐利,对年轻上颌中切牙根尖区解剖结构认识的提高,有助于年轻上颌中切牙根尖区病变的诊断、治疗与预后。