下颌第二磨牙远中邻面龋危险因素研究

目的研究导致下颌第二磨牙远中邻面龋的危险因素。方法收集558例下颌第三磨牙拔除病例数据,将下颌第二磨牙远中邻面龋与下颌第三磨牙的阻生类型、患者性别、年龄以及牙位等变量之间进行Logistic回归分析。结果 558例下颌第三磨牙拔除病例中,120例出现远中邻面龋。下颌第三磨牙阻生类型中的Pell-Gregory牙合平面分类（P=0.00〈0.01,OR=0.43〈1）和Winter分类（P=0.00〈0.01,OR=2.45〉1）以及性别（P=0.00〈0.01,OR=1.99〉1）、年龄（P=0.00〈0.01,OR=1.06〉1）进入Logistic回归方程。结论下颌第三磨牙在下颌骨内的位置越高,近中倾斜的角度越大,越容易导致下颌第二磨牙远中邻面龋。年龄越大,下颌第二磨牙远中邻面龋发生率越高,男性较女性更容易发生第二磨牙远中邻面龋。     

牙半切除术治疗下颌第二磨牙远中根面龋49例疗效观察

牙半切除术治疗下颌第二磨牙远中根面龋４９例疗效观察江苏省盐城市口腔医院口腔内科许海军，吕立秀下颌第三磨牙低位近中斜位阻生、垂直阻生、水平阻生常致使下颌第二磨牙远中龋坏达根面及远中深牙周袋、食物嵌塞，致使第二磨牙无法行牙体保存疗法，临床通常拔除第二、第...     

下颌第三磨牙萌出状态与第二磨牙远中邻面龋坏的相关性研究

目的:研究下颌第三磨牙萌出状态与第二磨牙远中邻面龋坏的相关性。方法 :临床收集因下颌第三磨牙不适而就诊的患者204例,运用锥形束CT分析下颌第二磨牙远中邻面龋坏与第三磨牙阻生类型(高位、中位、低位)、阻生角度以及两磨牙的釉牙骨质界距离(cementoenamel junction,CEJ)等因素是否存在相关性。结果:在下颌第三磨牙存在的情况下,第二磨牙远中邻面龋坏发生率高达78.4%;性别差异无统计学意义(P=0.165);高位、中位和低位阻生的龋坏发生率差异无统计学意义(P=0.646);而当第三磨近中阻生角度为40~80°时,第二磨牙远中邻面最易发生龋坏,与其他阻生角度组的差异有统计学意义(P<0.001);当第二磨牙与第三磨CEJ距离在6~9 mm时,第二磨牙远中邻面龋坏高于其他组,差异有统计学意义(P<0.001)。结论:下颌第三磨牙近中阻生角度、第三磨牙与第二磨牙的CEJ距离与第二磨牙远中邻面龋坏的发生密切相关。当第三磨近中阻生角度在40~80°间,且两磨牙间的CEJ距离在6~9 mm时,第二磨牙远中邻面更容易发生龋坏,此类阻生齿建议尽早拔除。     

下颌阻生第三磨牙阻生类型与第二磨牙损害相关性的影像分析

目的:探讨下颌第三磨牙的阻生情况,以及与相邻第二磨牙病损的相关性,为临床早期拔除高风险的下颌第三磨牙、预防第二磨牙病损提供依据。方法:根据纳入与排除标准,选择2015年9月—2017年9月在上海交通大学医学院附属第九人民医院放射科拍摄的全景片3000张（共4328颗下颌第三磨牙）,观察下颌第三磨牙阻生情况及相邻第二磨牙远中龋坏、牙周病、牙根吸收情况,使用R语言χ²检验统计分析其间的相关性。结果:阻生类型与第二磨牙病损均有相关性（P<0.001）;下颌第三磨牙近中阻生时,第二磨牙远中的龋坏率最高（P<0.001）;下颌第三磨牙垂直阻生和远中阻生时,第二磨牙的牙周病发生率最高（P<0.001）;下颌第三磨牙倒置阻生时,第二磨牙牙根吸收发生率最高（P<0.001）。结论:下颌阻生第三磨牙对其邻牙健康状况的影响程度较高,临床上建议早期拔除。     

下颌阻生第三磨牙X线分析

本文就３６８颗下颌阻生第三磨牙Ｘ线牙片进行了读片分析，结果表明：下颌第三磨牙以近中阻生最多，垂直阻生次之，水平阻生居第三。三类统共占全部阻生第三磨牙的９２．６６％。牙根数目以双根最多，单根次之。牙根形态以直根最多，远中弯曲根次之。有７５．００％的下颌阻生第三磨牙根尖与下颌管关系密切。６１．４％有冠周骨组织炎性病变，其中，远中骨吸收与垂直阻生关系密切，近中骨吸收与近中和水平阻生关系密切。第二磨牙远中邻面龋坏与近中阻生关系密切。作者认为下颌第三磨牙近中、水平阻生和存在冠周炎症的垂直阻生牙原则上均应拔除。Ｘ线牙片能全面确切地了解阻生牙的骨内情况，辅助阻力分析及手术方案的制定，对下颌第三磨牙拔除术是必要的，应作为术前常规。     

下颌阻生第三磨牙邻牙阻力的圆弧法分析

<正> 邻牙阻力是下颌阻生第三磨牙拔除时第二磨牙对该牙的胆力。一般认为近中斜位阻生、低位垂直阻生、低位水平阻生,大多数都嵌阻在邻牙远中面的接触点以下或与邻牙远中根接触,因而存在邻牙阻力。临床上常用肉眼观察法、探针法来确准邻牙远中面和阻生牙近中冠的接触方式,估计有无邻牙阻力,选择劈冠法     

牙半切除术联合固定修复在下颌第二磨牙保留中的应用

选择2007年4月至2009年4月在我科就诊患者45例45颗患牙.年龄23-54岁,其中男性26例,女性19例,均为下颌智齿阻生致第二磨牙远中根无法保留.其中第三磨牙水平阻生12例,近中阻生27例,垂直阻生6例.第二磨牙远中龋坏达根面以下20颗,第二磨牙远中牙周吸收至根尖1/3的29颗,第二磨牙远中龋坏致远中根根折6颗.保留患牙均具备成年人下颌非融合根第二磨牙;术前经X线片检查,欲保留牙根粗壮、根尖无明显阴影,牙周膜间隙无明显增宽,牙槽骨吸收不超过1/2,或经彻底根管、牙周治疗后达以上要求;下颌第二磨牙根分叉高度不低于近中根长度的2/3.     

下颌阻生智齿与第二磨牙患龋关系的探讨

本文收集下颌智齿阻生且同时有下颌第一、二磨牙的患者 112 0例 ,从性别、年龄、智齿阻生方向及在口内存留时间等方面 ,统计分析对下颌第二磨牙患龋的影响 ,并与同组病例下颌第一磨牙患龋率对照 ,现报告如下。临床资料门诊下颌智齿阻生病人 112 0例 ,下颌第一、二磨牙各2 180颗 ,男 989颗牙 ,女 1191颗牙 ,年龄 18～ 48岁。用口镜、镊子、探针、Ｘ线片或拔除阻生智齿等方法 ,检查智齿阻生方向及下颌第一、二磨牙患龋情况 ,询问阻生智齿萌出时间 ;智齿阻生方向按其长轴与下颌第二磨牙长轴关系分为垂直阻生、水平阻生、近中阻生、颊向阻生、舌…     

保留阻生牙金属联冠修复法

下颌第三磨牙近中阻生可引超下颌第二磨牙远中邻面龋及智齿冠周炎,严重者引起笫二磨牙远中牙槽骨吸收、牙齿松动而拔除。1985年元月以来我们采用保留阻生牙金属联冠修复36例病人,临床效果良好,现将有关方法及临床应用讨论如下:     

下颌阻生智齿对第二磨牙远中面的影响

下颌阻生智齿对第二磨牙远中面的影响山东省滨州医学院附属医院（２５６６０３）赵呈利邢学玲惠敏舒青媛下颌智齿阻生往往造成冠周炎、反复食物嵌塞、第二磨牙远中龋坏等并发症，临床中发现第二磨牙远中龋坏的发生率较高，危害较大。现报告如下。一般资料因下颌智齿阻生造...     

Distal cervical caries in the mandibular second molar: an indication for the prophylactic removal of third molar teeth? Update

In 2005 we reported the clinical findings of 100 patients who had mandibular third molars removed because of distal cervical caries in the mandibular second molar. The aim of this follow-up study was to find out whether the findings in a new group of patients corroborate those of our previous study. We report on the clinical features of 239 patients (mean (SD) age 32.1 (7.85) years, range 20–65) who had 288 mandibular third molars removed because of distal cervical caries in the second molar. Patients had better dental health than average, and 67% had a DMF (decayed, missing, or filled) score of 5 or less. In 89% of third molars the mesial angulation was between 40° and 80°. Distal cervical caries in second molars is a late complication of third molar retention. The prophylactic removal of a partially erupted mesioangular third molar will prevent distal cervical caries forming in the second molar tooth.     

Prevalence and factors affecting the formation of second molar distal caries in a Turkish population

The aim of this study was to evaluate the prevalence of second molar distal caries in a Turkish population and to determine the factors that affect it. Clinical records and panoramic radiographs of partially erupted mandibular third molars were reviewed in this retrospective study. The analysis outcome measures were the patients’ age, second molar distal caries, third molar angulation and second and third molar contact point localization. Prevalence of second molar distal caries in the population was 20%. This prevalence was 47% when the third molar had an angulation of 31–70° (majority of mesioangular third molars) and 43% at 70–90° (all horizontal third molars). The contact point on the second molar amelocemental junction and increasing age had significant effects on caries formation. The results revealed that second molar distal caries justifies prophylactic third molar removal and partially erupted third molars that have an angulation of 30–90° with a contact point on the amelocemental junction should be removed to prevent second molar distal caries.     

Vertical eruption patterns of impacted mandibular third molars after the mesialization of second molars using miniscrews

Objective:To investigate (1) whether vertical eruption of impacted third molars improves after mesialization of second molars and (2) what factors affect the vertical eruption of impacted third molars when space caused by missing molars is successfully closed by mesialization of the second molar using miniscrews.Materials and Methods:The treatment group (Group 1) included 52 patients who had (1) missing mandibular first molars (ML-6) or missing deciduous mandibular second molars (ML-E), (2) initially impacted mandibular third molars, and (3) successful space closure of the edentulous area with orthodontics. Panoramic radiographs at start of treatment (T1) and at time of space closure (T2) were collected. The control group (Group 2) included 46 nonedentulous patients with impacted mandibular third molars without molar protraction treatment. Panoramic radiographs with similar T1/T2 treatment times were selected. Nine measurements were obtained regarding horizontal available space, vertical eruption, and third molar angulation.Results:Third molars erupted vertically an average of 2.54 mm in Group 1 compared with 0.41 mm in Group 2. Age, gender, Nolla stage, and angle of the third molars did not show significant correlations with the vertical change of the impacted third molars, whereas the depth of third molar impaction and available space showed significant correlations.Conclusions:Impacted mandibular third molars vertically erupt as a result of uprighting with mesialization of the second molar, and vertical eruption is affected by the initial vertical location of impacted third molars and available space.     

Periodontal healing after ‘orthodontic extraction’ of mandibular third molars: A retrospective cohort study

In this study we investigated periodontal healing of mandibular second molars following ‘orthodontic extraction’ of adjacent impacted third molars, under the null hypothesis that there would be no difference in probing pocket depths (PPD) and clinical attachment levels (CAL) at the distal aspect of second molars before and after treatment. A retrospective survey was conducted of 64 patients who consecutively underwent ‘orthodontic extraction’ of mandibular third molars in close anatomical relationship with the mandibular canal from January 1997 to January 2011. Age, smoking habit, and PPD and CAL at the distal aspect of second molars before and after treatment were recorded. A statistically significant difference was found in PPD and CAL before and after treatment for the overall sample and for the sample classified by age (>25 or ≤25 years), smoking habit (smoker or non-smoker), and type of third molar impaction (horizontal, mesioangular, or vertical). Median PPD and CAL reductions amounted to 6 mm and 5 mm, respectively. The null hypothesis was rejected and orthodontic extraction proved to be indicated for those impacted mandibular third molars at high risk of a postoperative periodontal defect at the distal aspect of the adjacent second molar.     

Change in third molar angulation and position in young adults and follow-up periodontal pathology.

PURPOSE: This study was designed to assess changes in third molar position and angulation in young adults and the resulting third molar periodontal probing (PD) status. PATIENTS AND METHODS: Data derived from patients with 4 asymptomatic third molars with adjacent second molars enrolled in an institutional review board approved longitudinal trial. Inclusion criteria for the trial dictated that patients be healthy and 14 to 45 years of age. Panoramic radiographs were analyzed for third molar angulation as compared with the long axis of the second molar (mesial/horizontal > or =25 degrees ) and eruption to the occlusal plane. Full mouth PD including third molars was conducted at follow-up. At follow-up, PD > or =4 mm distal of second molars or around third molars was considered important clinically. RESULTS: Data from 237 patients were available. Median age was 25.9 years (interquartile range [IQ], 22.1 years, 32.8 years). With a median follow-up of 2.2 years (IQ, 2.0 years, 3.7 years), 44% of impacted maxillary third and 26% of impacted mandibular third molars changed angulation or position. One third of vertical/distal impacted third molars in both jaws and 11% mesial/horizontal mandibular third molars erupted to the occlusal plane during follow-up from baseline. If mandibular third molar angulation as compared with the long axis of the second molar was mesial/horizontal > or =35 degrees , only 3% erupted to the occlusal plane. At follow-up, 11% of the 125 impacted maxillary third and 29% of the 133 impacted mandibular third molars had PD > or =4 mm. Similarly, 11% of the 307 maxillary third molars at the occlusal plane had PD > or =4 mm, but 51% of the 312 erupted mandibular third molars were affected. CONCLUSION: A change in third molar position or angulation was common. Erupted mandibular third molars were more likely to have PD > or =4 mm.     

下颌第二磨牙龋损状况临床分析

目的: 统计分析下颌第二磨牙龋坏始发部位及严重程度, 并分析其与性别、年龄及下颌第三磨牙萌出状况的关系。方法: 采用临床与X线检查对481例下颌第二磨牙龋坏患者进行统计调查, 应用SPSS 13.0软件包对结果进行χ2检验。结果: 下颌第二磨牙龋坏多始发于面和远中邻面, 其次为颊面, 发生率分别为33.8%、33.2%、24.4%;累及牙髓的龋坏最多, 占49.7%, 深龋、浅中龋分别占31.7%、18.6%;男、女性别在龋坏部位分布总体上无显著差异;年龄与下颌第二磨牙的龋坏部位分布及严重程度有显著的相关性, 随着年龄增大, 面和远中邻面龋坏增多, 程度加重;下颌第三磨牙萌出状况对下颌第二磨牙龋坏影响显著。结论: 下颌第二磨牙始发龋坏牙面以面及远中邻面最多, 龋损程度严重, 年龄、下颌第三磨牙萌出状况与龋坏状态关系密切。预防性拔除异常萌出的下颌第三磨牙及定期检查, 是预防和早期治疗下颌第二磨牙龋坏的有效措施。     

Third molar impaction in the Jazan Region: Evaluation of the prevalence and clinical presentation

ObjectiveTo provide information on the prevalence and clinical features of impacted third molar teeth in the South-Western region of Saudi Arabia.Material and methodsIn this cross-sectional study, 1200 panoramic radiographs (50% males and 50% females) were retrieved from the electronic clinical records of patients at the College of Dentistry, Jazan University from December 2014 to December 2016, and impacted third molars were evaluated. Data on clinical and radiographic presentation were analyzed.ResultsOverall, there were 291 (24.3%) patients with impacted third molars among 1200 radiographs. The distribution of impacted third molars according to the number of impacted teeth was as follows: one impaction in 121 (41.6%); two impactions in 90 (30.9%); three impactions in 42 (14.4%); and four impactions in 38 (13.1%) patients. There was a high prevalence of all impaction types among females (54.5%). Maxillary vertical angulation was most common (50%) followed by mandibular mesioangular angulation (48.3%). The depth of impaction in maxillary teeth was higher than in mandibular teeth. Pain was uncommon (4.5% of patients).DiscussionClinically, vertical impaction in the maxilla was present in 50% of patients because of limited posterior space, and mesioangular angulation in the mandible was present in 48% of patients because of inadequate space between the ramus and the second molar. These findings are similar to other reports. Vertical impaction of the maxillary wisdom tooth is mostly related to the discrepancy between the mesiodistal size of the tooth crown and the limited retromolar space.ConclusionNoiseless presentation of an impacted third molar requires raising the population’s awareness about the need for diagnosis and treatment of the problem to avoid any further complications. The study can be to guide surgical procedures. This study documented the prevalence, pattern, and clinical features of impacted third molars in South Western region of Saudi Arabia.     

External root resorption of the second molar associated with mesially and horizontally impacted mandibular third molar: evidence from cone beam computed tomography

Objectives

The aim of the present study was to assess the incidence and risk factors of ERR in second molars with mesially and horizontally impacted mandibular third molars using cone beam computed tomography (CBCT) images from patients in a Chinese tertiary referral hospital.

Materials and methods

A total number of 216 patients with 362 mesially and horizontally impacted mandibular third molars who were treated at our institution from 2014 to 2015 was retrospectively included. The ERR in second molars was identified on CBCT multiplanar images. The associations between incidence of ERR and multiple clinical parameters were statistically analyzed by Chi-square test. Moreover, the risk factors for ERR in second molars were further assessed by multivariate regression analysis.

Results

The overall incidence of ERR in second molars was 20.17 % (73/362) as detected on CBCT images. The presence of ERR significantly associated with patients age and impaction depth of mandibular third molars. However, no significant relationship was found between ERR severity and impaction depth or ERR location. Multivariate regression analyses further revealed age over 35 years and impaction depth as important risk factors affecting the ERR incidence caused by mesial and horizontal impaction of mandibular third molar.

Conclusions

ERR in second molar resulted from mesially and horizontally impacted mandibular third molar is not very rare and can be reliably identified via CBCT scan.

Clinical relevance

Given the possibility of ERR associated with third molar impaction, the prophylactic removal of these impacted teeth could be considered especially for those patients with over 35 years and mesially and horizontally impacted teeth.

     

Residual periodontal defects distal to the mandibular second molar 6-36 months after impacted third molar extraction

AIM: This retrospective study investigated the periodontal conditions distal to mandibular second molars 6-36 months after routine surgical extraction of adjacent impacted third molars. METHOD: Subjects were randomly selected by systematic sampling from computer records of 3211 surgical mandibular third molar extractions in the Hong Kong dental teaching hospital. Records and pre-extraction radiographs of the selected cases were retrieved. Selected subjects (n = 283) were invited for an interview followed by a clinical examination. Community Periodontal Index (CPI) protocol was used for the assessment of the general periodontal status (excluding the mandibular second molar of interest, i.e. the subject tooth) followed by a detailed periodontal examination of the subject tooth. RESULTS: In all, 158 subjects, aged 29 +/- 7 years, were examined with only 6% (nine subjects) having a highest CPI score of 4 (excluding the subject tooth), but local periodontal defects were prevalent at the distal surface of subject mandibular second molars: mean probing pocket depth (PPD) was 5.4 +/- 1.9 mm with 67% (106 subjects) exhibiting PPD >or= 5 mm and 23% (36 subjects) exhibiting PPD >or= 7 mm; mean recession was 0.8 +/- 1.0 mm; bleeding on probing 96% and suppuration on probing 5%. Multiple linear regression analysis was used to analyse the effects of 12 independent variables on the PPD at the distal surface of the involved mandibular second molar. Three possible risk indicators (P < 0.001, R2 = 0.27) associated with localised increased PPD at the distal surface of the mandibular second molars were identified: 1) third molar 'mesio-angular' impaction; 2) pre-extraction crestal radiolucency and 3) inadequate post-extraction local plaque control. CONCLUSION: The results suggest that periodontal breakdown initiated and established on the distal surface of a mandibular second molar in the vicinity of a 'mesio-angular' impacted third molar evidenced by pre-extraction crestal radiolucency in association with inadequate plaque control after extraction can predispose to a persistent localised periodontal problem.