高位J钩引起牙根吸收的临床观察

目的:评价标准方丝弓配合高位J钩对正畸治疗中牙根吸收的影响。方法:随机选择60例经过标准方丝弓技术治疗的安氏Ⅰ类或Ⅱ类Ⅰ分类伴上颌前突年轻女性患者,其中30例在内收前牙阶段应用高位J钩配合治疗。治疗前后拍摄全颌曲面断层片,分别测量2组治疗前后上颌4个切牙的牙根吸收等级,并经计算机进行χ2检验。结果:2组正畸治疗后均有明显的牙根吸收,治疗前后牙根吸收等级比较,2组均有显著性差异(P<0.01)。治疗后2组间牙根吸收等级比较,差异也呈显著性(P<0.01),标准方丝弓配合高位J钩组还出现了极重度吸收。结论:标准方丝弓配合高位J钩在正畸治疗中较单纯使用标准方丝弓技术更易产生严重的牙根吸收。     

Apical root resorption in patients treated with comprehensive orthodontics

External apical root resorption (EARR) is a common--but seldom extreme--consequence of orthodontic treatment. Incisors are most at risk, perhaps because of their single roots and because they typically are moved farther than other teeth. We followed a cohort of patients (n = 153) treated with comprehensive orthodontics. EARR was scored on the upper incisors with a qualitative five-grade ordinal scale. There was no EARR at the start of treatment, but most (> 80%) exhibited slight-to-moderate EARR by the end of treatment (i.e., a loss of 1-2 mm). Cases treated with premolar extractions experienced more EARR because their incisors were retracted farther; however, the sum of the effects of patients' sex and age, and severity of the malocclusion, and the kind of mechanics used accounts for little of the overall variation in EARR. Instead, it appears that genetically-based inter-individual variation in susceptibility to EARR is the most influential factor. Research should be directed at understanding the biochemical nature of susceptibility so prospective patients can be screened to identify those at particular risk.     

Predicting and preventing root resorption: Part I. Diagnostic factors.

The purpose of this study was to determine whether it would be possible to identify pretreatment factors that will allow the clinician to predict the incidence, location, and severity of root resorption before the commencement of orthodontic treatment. The records of 868 patients who were treated with full, fixed edgewise appliances were obtained from 6 private offices; full-mouth periapical radiographs were used to accurately assess apical root resorption from first molar to first molar in both arches. The results showed that resorption occurs primarily in the maxillary anterior teeth, averaging over 1.4 mm. The worst resorption was seen in maxillary lateral incisors and in teeth with abnormal root shape (pipette, pointed, or dilacerated). Adult patients experienced more resorption than children did in the mandibular anterior segment only. Asian patients were found to experience significantly less root resorption than white or Hispanic patients. Increased overjet, but not overbite, was significantly associated with greater root resorption. There was no difference in either the incidence or severity of root resorption between male and female patients.     

External apical root resorption following orthodontic treatment

This study investigated the association of appliance type and tooth extraction with the incidence of external apical root resorption (EARR) of posterior teeth following orthodontic treatment. Pre- and posttreatment orthopantomograms were compared for 97 patients and a 4-grade ordinal scale used to measure EARR. The incidence of EARR was positively associated with tooth position (P < .001), appliance type (P = .038), and extractions (P = .001). This was observed in an overall analysis mutually adjusted for the effects of age at start of treatment, pretreatment overbite and overjet, use of headgear, tooth extraction, and type of appliance. The incidence of EARR was 2.30 times higher for Begg appliances compared with edgewise, and it was 3.72 times higher where extractions were performed.     

External apical root resorption in maxillary root-filled incisors after orthodontic treatment: a split-mouth design study

Introduction: The purpose of this study was to compare, in a split mouth design, the external apical root resorption (EARR) associated with orthodontic treatment in root-filled maxillary incisors and their contralateral teeth with vital pulps. Methodology: The study sample consisted of 38 patients (14 males and 24 females), who had one root-filled incisor before completion of multiband/bracket orthodontic therapy for at least 1 year. For each patient, digital panoramic radiographs taken before and after orthodontic treatment were used to determine the root resortion and the proportion of external root resorption (PRR), defined as the ratio between the root resorption in the endodontically treated incisor and that in its contralateral incisor with a vital pulp. The student’s t-test, chi-square test and logistic regression analysis were used to determine statistical significance. Results: There was no statistically significant difference (p > 0.05) between EARR in vital teeth (1.1 ± 1.0 mm) and endodontically treated incisors (1.1 ± 0.8 mm). Twenty-six patients (68.4%) showed greater resorption of the endodontically treated incisor than its homolog vital tooth (p > 0.05). The mean and standard deviation of PPR were 1.0 ± 0.2. Multivariate logistic regression suggested that PRR does not correlate with any of the variables analyzed. Conclusions: There was no significant difference in the amount or severity of external root resorption during orthodontic movement between root-filled incisors and their contralateral teeth with vital pulps. Key words:Endodontics, orthodontics, root canal treatment, root resorption.     

正畸牙移动早期牙根吸收的临床研究

目的 应用锥体束计算机断层(Cone beam computed tomography,CBCT)技术分析正畸牙移动早期牙根吸收的发生情况及其影响因素.方法 选择108例正畸患者,432颗上切牙,治疗前及治疗5～9个月,平均(6.9±1.24)个月后分别拍摄上颌4个切牙CBCT.记录患者性别、初诊年龄、拔牙与否、安氏分...     

自锁矫治与传统矫治对牙根吸收的影响

目的:探讨自锁托槽轻力矫治是否可以减轻对牙根的吸收。方法:选取临床治疗的安氏Ⅰ、Ⅱ类拥挤并拔除4颗第一前磨牙病例30例,分为2组。其中,15例使用Damon 3MX自锁托槽矫治(自锁组),15例使用传统结扎式直丝托槽矫治(结扎组)。2组资料矫治前在性别、年龄、拥挤度及错类型等指标上具有可比性。通过矫治前、后的模型及全口曲面体层片,测量计算2组矫治后上、下切牙牙根吸收量,应用SPSS19.0软件包对数据进行t检验分析。结果:①上颌中切牙牙根吸收自锁组为(2.05±1.51)mm,结扎组为(2.08±1.21)mm,差异无显著性(P=0.973>0.05)。②上颌侧切牙牙根吸收自锁组为(1.77±1.01)mm,结扎组为(1.91±1.59)mm,差异无显著性(P=0.848>0.05)。③下颌中切牙牙根吸收自锁组为(2.06±1.62)mm,结扎组为(1.98±1.50)mm,差异无显著性(P=0.926>0.05)。④下颌侧切牙牙根吸收自锁组为(1.94±1.45)mm,结扎组为(1.84±1.17)mm,差异无显著性(P=0.888>0.05)。结论:在拔牙正畸中,自锁矫治并未表现出比传统结扎矫治更少的牙根吸收。     

Is mild dental invagination a risk factor for apical root resorption in orthodontic patients?

The purpose of this retrospective study was to assess if dental invagination is a risk factor for root resorption during orthodontic treatment. The sample consisted of 91 patients (32 males, 59 females) with a mean age of 13.1 years (range 9.3-32.1 years) with complete orthodontic records, including periapical radiographs of the maxillary incisors before and after treatment. Forty-nine patients had at least one maxillary incisor invaginated, whilst the remaining 42 patients were free of dental invaginations. Variables recorded for each patient included gender, age, Angle classification, extraction or non-extraction therapy, ANB angle, overjet, overbite, trauma, habits, agenesis, tooth exfoliation, treatment duration, Class II elastics, body-build, general factors, impacted canines, and root form deviation. Crown and root length of the maxillary incisors were measured on pre- and post-treatment long cone periapical radiographs corrected for image distortion. The percentage of root shortening and root length loss in millimetres was then calculated. Most of the invaginated teeth were minor type 1. Statistical analysis revealed no significant difference in the severity of apical root resorption between invaginated and non-invaginated incisors in patients without dental invaginations, nor was the extent of dental invagination related to the severity of apical root resorption. However, invaginated teeth had malformed roots more often than non-invaginated teeth. Dental invagination, and particularly type 1, cannot be considered a risk factor for apical root resorption during orthodontic tooth movement.     

Evaluation of maxillary central incisors on the noncleft and cleft sides in patients with unilateral cleft lip and palate—Part 2: Relationship between root resorption,horizontal tooth movement,and quantity of grafted autogenous bone

Objective:To evaluate the relationship between external apical root resorption (EARR) of the maxillary central incisors (U1), horizontal orthodontic tooth movement, and quantity of grafted bone in subjects with unilateral cleft lip and palate (UCLP) over an average duration of 8 years.Materials and Methods:Thirty subjects with UCLP were evaluated for EARR of U1 after edgewise treatment (T2). The teeth were classified as having no EARR, moderate EARR (combined into “no/moderate” EARR), or severe EARR. Frontal cephalometric radiographs acquired at eruption of U1 (T0), less than 6 months before secondary alveolar bone grafting (T1), and T2 were evaluated to determine the horizontal inclination (U1-axis angle) and distance of the root apex from the median line (U1-root–VL distance). On the cleft side, the quantities of grafted bone at less than 12 months postsecondary bone grafting and at T2 were evaluated using the alveolar bone graft (ABG) scale.Results:Cleft-adjacent teeth exhibited more severe EARR than did teeth on the noncleft side. The cleft side exhibited greater changes in U1-axis angle and U1-root–VL distance between T0 and T2 than did the noncleft side. On the cleft side, the ABG score at T2 in the severe EARR group was significantly lower than that in the no/moderate EARR group. These measurements were correlated with EARR grade.Conclusions:Cleft-adjacent U1 exhibited more severe EARR than did the U1 on the noncleft side, which might be associated with orthodontic treatment-induced changes in horizontal inclination and root apex movement. On the cleft side, severity of EARR may be correlated with the success of ABG.     

Comparative study of root resorption of maxillary incisors in patients treated with lingual and buccal orthodontics

Objective:To compare the magnitude of external apical root resorption (EARR) of maxillary incisors in patients with mild to moderate anterior crowding, treated with lingual and conventional (labial) orthodontics.Materials and Methods:The sample comprised 40 patients divided into two groups: lingual (20 patients) and conventional buccal brackets (20 patients). Patient ages ranged from 11 to 45 years, and the study included 12 men and 28 women. Apical root resorption was measured from periapical radiographs obtained at the beginning of treatment (T1) and at the end of the leveling phase (T2). Periapical radiographs were scanned and transferred to the CorelDraw X7 image-processing program, in which measurements of root lengths were performed. For intragroup and intergroup comparisons between the T1 and T2 phases, paired and independent t-tests, respectively, were used at 5% significance.Results:There was significant apical root resorption for all teeth evaluated; the magnitude of the EARR (T2−T1) ranged from −0.35 mm to −0.63 mm in the lingual group, and from −0.66 mm to −0.85 mm in the conventional group. Although there was an intergroup variation in the magnitude of EARR observed, no statistically significant differences were found. Neither group presented any teeth with resorption ≥1 mm.Conclusions:The magnitude of apical root resorption in maxillary incisors in patients with anterior crowding was similar regardless of orthodontic technique, lingual or conventional. Both techniques resulting in an apical rounding considered clinically insignificant.     

The influence of orthodontic treatment on previously traumatized permanent incisors.

The reaction of previously traumatized teeth to orthodontic force application was investigated. Four groups of children were examined: group T comprised 56 children who encountered trauma to their maxillary incisors; group O comprised 29 orthodontic patients with intact incisors; group TO comprised 28 previously traumatized orthodontic patients; and group C served as the control group (n = 26). Orthodontic treatment was restricted to tipping movement executed only by means of removable appliances. Groups T, O, and TO were followed up longitudinally by means of clinical and radiographic examinations. In most of the cases the reported trauma occurred to teeth with completed roots and affected the crown only. Group TO presented the highest, though relatively moderate, prevalence of root resorption (27.8 per cent) and was followed by groups O and T (6.7 and 7.8 per cent, respectively) while in the control group no resorption was observed. Electrical pulp testing revealed the highest prevalence of loss of tooth vitality in group TO (7.3 per cent) in which the highest prevalence of pulp obliteration was also found. It can be concluded that the combination of trauma with orthodontic tipping renders the teeth more susceptible to complications, especially to root resorption and loss of vitality.     

Apical root resorption after orthodontic treatment -- a retrospective study

The purpose of the study was to compare the incidence and severity of apical root resorption in patients treated with different orthodontic appliances and to evaluate the effect of treatment duration on the degree of apical root resorption. A further aim was to analyse the degree of apical root resorption in different tooth groups in patients presenting with root resorption. The sample consisted of 625 patients (269 males, 356 females) aged 8-16 years at the beginning of treatment. Active removable plates and fixed appliances were used most frequently. Following exclusion of poor quality radiographs, the final sample included 601 patients (348 females, 253 males). Root resorption in all tooth groups, except third molars, was evaluated from pre- and post-treatment panoramic radiographs. The correlation of root resorption with treatment modality and duration was studied using multinomial logistic regression analysis. Of the tooth groups, maxillary incisors showed apical root resorption most frequently, followed by the mandibular incisors. Root resorption was significantly correlated with fixed appliance treatment (P < 0.001). In addition, the duration of fixed appliances treatment was found to contribute significantly (P < 0.01) to the degree of root resorption. The mean duration of treatment in patients without root resorption was 1.5 years, whereas in those with severe resorption was 2.3 years. The most severe resorption was seen in the maxillary incisors and premolars. It is concluded that with a long duration of fixed appliance treatment, the risk of severe resorption increases. In patients where treatment is prolonged, a 6-month radiographic follow-up is recommended.     

A radiographic analysis of external apical root resorption of maxillary incisors during active orthodontic treatment

External apical root resorption (EARR) is an undesirable consequence of orthodontic treatment. The purpose of this study was to measure the amount of EARR and to examine its clinical significance in maxillary incisors, during a 12-month active treatment period. A further aim was to examine the contribution of gender, treatment technique, treatment duration, and extraction of maxillary first premolars to EARR. The sample comprised 151 maxillary incisor teeth in 40 patients (16 males, 24 females) aged 12-22 years, with different malocclusions. Standard periapical radiographs, using the long-cone paralleling technique, were obtained before and 6 and 12 months after the start of treatment. Quantitative measurements for 80 central and 71 lateral maxillary incisors were performed separately and corrected for image distortion. Root length reduction was calculated in millimetres and in terms of the percentage of the original root length. Resorption of more than 1 mm at 12 months of active treatment was considered to be clinically significant. On average, the degree of EARR for the maxillary central incisors was 0.77 +/- 0.42 and 1.67 +/- 0.64 mm, respectively, during the 6- and 12-month follow-up (P < 0.001). For the lateral incisors, the degree of EARR was 0.88 +/- 0.51 and 1.79 +/- 0.66 mm, respectively (P < 0.001). Clinically significant resorption was found for 74 per cent of the centrals and 82 per cent of the laterals. No significant correlation was observed between EARR and treatment technique. EARR was found to be correlated with gender for the lateral incisors. The effect of treatment duration (P < 0.001) and premolar extraction (P < 0.001) was statistically significant for both tooth groups.     

青少年正畸治疗中影响牙根吸收的因素探讨

目的：探讨影响青少年错[牙合]畸形患者正畸矫治后牙根吸收的相关因素。方法：选择已完成正畸固定矫治的青少年患者78例．在其矫治前后的曲面断层片上,对4个上切牙进行根尖形态的分析,以获得正畸矫治后牙根吸收的定性数据。在对受试者按年龄、性别、牙位、牙龄、拔牙与否及疗程分组后,利用SPSS12．0软件对所得数据进行非参数检验分析。结果：所有正畸患者都存在一定程度的牙根吸收,根尖形态分析显示：①牙龄ⅣA期患者比ⅢC期的患者存在更严重的牙根吸收（P〈0．01）,但按年龄比较不存在显著差异;②拔牙组比不拔牙组有更加严重的牙根吸收（P〈0．01）;③疗程越长,牙根吸收也越明显（P〈0．05）;④牙根吸收的严重程度与性别及上切牙牙位之间无相关性。结论：在第二恒磨牙完全建验前（ⅣA期前）进行正畸治疗、不拔牙矫治、缩短矫治疗程,均可以减少正畸治疗中的牙根吸收。     

应用CBCT研究不同矫治器正畸拔牙矫治对前牙区牙根及牙槽骨的影响

目的 应用CBCT研究无托槽隐形矫治及传统固定矫治器正畸拔牙对前牙区牙根及牙槽骨的变化情况.方法 选择成人拔牙矫正的患者60例,随机分为无托槽隐形矫治器组及传统固定矫治器组(N=30).正畸治疗前后拍摄CBCT,测量两组正畸患者上下颌中切牙、侧切牙、尖牙的牙根长度及牙槽骨的厚度变化情况.结果 固定矫治器组较无托槽隐形矫...     

Association between root resorption incident to orthodontic treatment and treatment factors

The purpose of this study was to clarify the prevalence and degree of root resorption induced by orthodontic treatment in association with treatment factors. The files of 243 patients (72 males and 171 females) aged 9-51 years were randomly selected from subjects treated with multi-bracket appliances. The severity of root resorption was classified into five categories on radiographs taken before and after treatment. The subjects were divided into extraction (n = 113 patients, 2805 teeth) and non-extraction (n = 130 patients, 3616 teeth) groups and surgical (n = 56 patients, 1503 teeth) and non-surgical treatment (n = 187 patients, 4918 teeth) groups. These subjects were also divided into two or three groups based on the duration of multiloop edgewise archwire (MEAW) treatment, elastic use, and total treatment time: 0 month (T1; n = 184 patients, 4831 teeth), range 1-6 months (T2; n = 37 patients, 994 teeth), more than 6 months (T3; n = 22 patients, 596 teeth); range 0-6 months (n = 114 patients, 3016 teeth) more than 6 months (n = 129 patients, 3405 teeth); range 1-30 months (n = 148 patients, 3913 teeth) and more than 30 months (n = 95 patients, 2508 teeth). The prevalence of overall and severe root resorption evaluated by the number of subjects and teeth was compared with a chi-square test. A Student's t-test for unpaired data was used to determine any statistically significant differences. The prevalence of severe root resorption based on the number of teeth was significantly higher in the group with extractions (P < 0.01). Longer use of a MEAW appliance and elastics also produced a significantly higher prevalence of root resorption (P < 0.05). On the other hand, the prevalence of severe root resorption was not significantly different between the subjects treated with or without surgery, but there was a significant increase when treatment time was prolonged (P < 0.05). A significant difference was found in the amount of root movement of the upper central incisors and the distance from their root apices to the cortical bone surface (P < 0.05). These are regarded as essential factors in the onset of root resorption. These results indicate that orthodontic treatment with extractions, long-term use of a MEAW appliance and elastics, treatment time, and distance of tooth movement are risk factors for severe root resorption.     

Early Orthodontic Treatment of Class-III Malocclusion in Germany

In order to evaluate current attitudes to early interceptive treatment, 2001 orthodontic offices in Germany were asked to fill in a questionnaire comprising the following topics: indication, appliances for the early correction of Class-III malocclusions, diagnostic records, duration, and benefits to overall therapy. Based on the 677 evaluable questionnaires, the following statistically significant conclusions could be drawn: 92.6% of the orthodontists see Class-III malocclusion as an indication for early treatment. Early treatment of severe crowding, diastemata, Class-II malocclusion, deep bite, increased overjet and impacted incisors was declined by most orthodontists. The interceptive treatment of further malocclusions was controversially discussed. Functional appliances (67.5%), in particular the Fr?nkel III (47.3%), were dominant in correction of Class-III malocclusions. Typical orthodontic records relating to early interceptive treatment include panoramic radiographs, lateral headfilms, photos and dental casts. 2.5% of the orthodontists routinely take a hand-wrist radiograph. Although recently published studies support the use of facial masks in theory, they are rarely used in practice. To what extent early interceptive treatment of Class-III malocclusion influences the overall treatment is the subject of further studies.     

三种矫治器治疗安氏Ⅱ类2分类对切牙牙根吸收的影响

目的 比较不同矫治器治疗安氏Ⅱ类2分类错牙合畸形患者切牙牙根的吸收状况。方法 选择使用不同矫治器的安氏Ⅱ类2分类成年患者30例,其中传统MBT托槽、自锁托槽以及无托槽隐形矫治器的患者各10例,共计240颗切牙。收集患者治疗前后的锥形束CT(CBCT)影像学资料,并导入Dolphin Imaging软件,Mimics软件以及3-Matics软件测量分析治疗前后切牙牙根吸收情况。结果 传统MBT托槽组和自锁托槽组的上下颌中切牙以及侧切牙的牙齿长度(L)与无托槽隐形矫治器组上下颌中切牙及上颌侧切牙的牙齿长度治疗后较治疗前显著减小,差异具有统计学意义。使用无托槽隐形矫治器的患者下颌侧切牙治疗前后的牙齿长度无显著变化。而三组之间的对比,上下颌中切牙牙齿长度变化无显著统计学差异。无托槽隐形矫治器组上下颌侧切牙的牙齿长度减少量相对更低,差异具有统计学意义(P＜0.05)。此外,无托槽隐形矫治器组平均牙齿长度变化为(-0.37±0.11)mm,显著小于传统MBT托槽组(-1.32±0.47)mm及自锁托槽组(-1.05±0.38)mm。在牙根吸收区域的比较上,各组均表现为腭侧吸收多于唇侧吸收,近中吸收多于远中吸收。结论 无托槽隐形矫治器治疗安氏Ⅱ类2分类错牙合畸形可有效降低切牙牙根吸收严重程度。     

Prevalence of Defined Symptoms of Malocclusion among Probands Enrolled in the Study of Health in Pomerania (SHIP) in the Age Group from 20 to 49 Years

SUBJECTS AND METHODS: SHIP is a complexly structured, population-based cross-sectional study of adults in the German region of Pomerania (age group covered: 20-79 years). Findings in a population subgroup (age group 20-49 years; n = 1777; 53.1% women; 46.9% men) were subjected to orthodontic evaluation. Graduated registration of anterior crowding, overjet, frontal overbite and sagittal intermaxillary relationship of the posterior teeth; registration of ectopic canines, posterior crowding, anterior and posterior crossbite, negative overjet, retroclination of the upper incisors, buccal nonocclusion, and lateral open bite. The prevalence of almost regular dentition and of symptoms of malocclusion as well as the frequency of orthodontic treatment (subjective patient data) undergone by men and women were recorded. The correlation between the registered symptoms of malocclusion was calculated. RESULTS: 92.2% of the subjects had symptoms of malocclusion varying in number and severity. An anatomically correct dentition was found in only 7.8% of cases, and an "almost regular dentition" (inclusion criteria defined) in 14.2%. 32.8% of the subjects had severe malocclusion (inclusion criteria defined). The most frequent symptoms were anterior crowding, increased overjet, and distoclusion. These symptoms were significantly more frequent in women, while spacing and edge-to-edge bite, excessive overbite and mesioclusion were more frequent in men. 26.7% of the probands (28.0% women, 25.3% men) reported having received orthodontic treatment. The prevalence of craniofacial malformations (cleft lip and palate, syndromes) was 0.09% in women and 0.2% in men. Increased overjet was most frequently correlated with other symptoms of malocclusion.     

埋伏弯根上颌中切牙序列矫治的研究

目的探讨埋伏弯根上颌中切牙有效的正畸牵引治疗方法。方法选择11例患者共12颗埋伏弯根上颌中切牙为研究对象,常规拍摄定位X线片,配合口内检查、模型分析等,确定埋伏牙的位置及其与邻牙的相互关系,采用封闭式导萌、选择性根管治疗及根尖切除术、修复治疗等方法进行矫治。结果12颗埋伏牙通过治疗后顺利进入正常牙列,未见牙根吸收粘连,建立了良好的咬合关系。9例唇侧埋伏弯根上颌中切牙患者的临床牙冠唇倾角度较大,4例根尖位于唇侧黏膜下,进行了根管治疗加根尖切除术,其中1例行烤瓷冠改形修复;其余5例未做根管治疗,暂行观察。2例腭侧埋伏弯根上颌中切牙的疗效稳定。结论埋伏弯根上颌中切牙采用序列矫治可以取得良好的美观和功能效果。