Relationship between alignment conditions of teeth in anterior segments and dental health

The purpose of the study was to examine the association between alignment conditions of anterior teeth and dental health in 15-year-old adolescents. The study group consisted of 74 females and 70 males with 6 anterior teeth in both jaws. The following parameters were assessed: plaque index (P1I), gingival index (GI), probing depth (PD), space index (SpI), filled surfaces (FS), and the NONAS-i.e., the number of non-aligned proximal tooth surfaces in each jaw counted on model casts. Statistical examination of the data was performed using chi 2 tests of association and homogeneity and correlation coefficient analyses. In both sexes and both jaws, anterior tooth segments with none or few non-aligned teeth had a more favourable periodontal state than segments with an increased number of non-aligned teeth. Likewise, tooth segments with none or few non-aligned teeth had a reduced frequency of proximal fillings compared to segments with an increased number of non-aligned teeth. In males, the distribution of restorations in the anterior segment of the lower jaw was relatively homogeneous in the 3 groups.     

Relationship between incisal tooth wear and the increasing number of permanent teeth in children and adolescents

summary The material presented in this report was derived from a longitudinal study of the development and progress of incisal tooth wear in children and adolescents. The study group was established in 1991/1992 and consisted of 77 participants between 8 and 15 years old. All participants were re-examined in 1994. The interval between the first and second examination was approximately 32 months. Each participant was scored for tooth wear of the anterior teeth of both jaws according to the Incisal wear Index (IwI) and the number of permanent teeth and the tooth types present were recorded at each examination. The results showed that the pattern of incisal wear had been maintained during the observation period. Severity of incisal wear increased as the number of teeth increased. The strength of the relationship between incisal wear and the number of teeth decreased during the observation period. At the same time, the number of teeth and the size of the wear increments were negatively correlated indicating that the rate of wear progression decreased as the number of teeth increased.     

Relationship between occlusal wear of the teeth and periodontal health

abstract – The study was undertaken in order to examine the relationship between occlusal wear and periodontal health in thc maxillary and mandibular anterior, premolar and molar regions of the human dentition. The occurrence and degree of attrition was recorded for the 4,316 fully erupted teeth of 154 males aged 19–22 years. The mandibular central incisors and the canines of both jaws were found most often to show attrition. In general, occlusal wear was found to be associated with improved cleanliness, and thus, in most areas of the dentition, also with improved periodontal conditions. At the openings of the major salivary glands, however, more calculus was found on attrited than intact teeth, and consequently, no improvement of the periodontal status was found in mandibular anterior teeth and maxillary molars. As the degree of attrition was not influenced by the frequency of toothbrushing, it seems evident that the masticatory function which results in occlusal wear of the teeth, has an effect per se on periodontal health.     

Longitudinal relationship between incisal tooth wear and periodontal condition

The purpose of the study was to examine the relationship between the longitudinal development of incisal tooth wear and periodontal conditions in 51 persons. Stone casts obtained at the ages of 15 and 27 yr were used to assess incisal wear according to a graded scale, the Incisal wear Index (Iwl). The wear increase after 12 yr, ΔIwI, was related to the various health index scores at the age of 15 yr, including the Plaque Index (PII) and Gingival Index (GI) systems. The chi-square tests showed a statistically significant association between AIwI and periodontal condition in 15-yr-olds. Thus, relatively low P1I and GI values were accompanied by relatively high AIwI values. It was concluded that in 15-yr-olds, P1I and GI levels are clinical predictors of future wear (ΔIwI) of maxillary and mandibular central incisors. Pocket depth (PD) was a less valuable clinical predictor of such wear.     

No association between incisal tooth wear and temporomandibular disorders

STATEMENT OF PROBLEM: Incisal tooth wear may be a sign of long-term bruxing behavior. Bruxism is purported to be a risk factor for temporomandibular disorders (TMD). PURPOSE: The purpose of this clinic-based case-control study was to investigate whether the wear of anterior teeth is associated with TMD. MATERIAL AND METHODS: Two hundred eight TMD patients and 172 control subjects were selected for participation. After exclusion of subjects with more than 1 missing premolar or molar zone in opposite arches, as well as subjects with missing or severely restored anterior teeth, 154 TMD patients and 120 control subjects were included in the study (age 31.2 +/- 13.4 years; range 13 to 76 years). Anterior tooth wear was assessed on casts with a 0 to 5 scale. A multiple logistic regression analysis, controlling for the effects of age and gender, was performed to investigate the relationship between tooth wear and TMD. RESULTS: An odds ratio of 0.76 (95% confidence interval: 0.51 to 1.15) indicated that after adjusting for gender and age, the odds in favor of TMD decreased an estimated 24% for each additional unit of the mean tooth wear score. This result was not significant (P=.20). CONCLUSION: Within the limitations of this study, incisal tooth wear (assessed on dental casts) was not significantly associated with TMD when the influence of age and gender was controlled. Based on these findings, a clinically relevant risk for TMD from incisal tooth wear can be excluded. Hence, the presented evidence does not support the idea that treatment of incisal tooth wear is indicated to prevent TMD.     

Quantification of incisal tooth wear in upper anterior teeth: Conventional vs new method using toolmakers microscope and a three-dimensional measuring technique

Objectives

This study aimed to quantify tooth wear in upper anterior teeth using a new CAD-CAM Laser scanning machine, tool maker microscope and conventional tooth wear index.

Methods

Fifty participants (25 males and 25 females, mean age = 25 ± 4 years) were assessed for incisal tooth wear of upper anterior teeth using Smith and Knight clinical tooth wear index (TWI) on two occasions, the study baseline and 1 year later. Stone dies for each tooth were prepared and scanned using the CAD-CAM Laser Cercon System. Scanned images were printed and examined under a toolmaker microscope to quantify tooth wear and then the dies were directly assessed under the microscope to measure tooth wear. The Wilcoxon Signed Ranks Test was used to analyze the data.

Results

TWI scores for incisal edges were 0–3 and were similar at both occasions. Score 4 was not detected. Wear values measured by directly assessing the dies under the toolmaker microscope (range = 113–150 μm, mean = 130 ± 20 μm) were significantly more than those measured from Cercon Digital Machine images (range = 52–80 μm, mean = 68 ± 23 μm) and both showed significant differences between the two occasions.

Conclusions

Wear progression in upper anterior teeth was effectively detected by directly measuring the dies or the images of dies under toolmaker microscope. Measuring the dies of worn dentition directly under tool maker microscope enabled detection of wear progression more accurately than measuring die images obtained with Cercon Digital Machine. Conventional method was the least sensitive for tooth wear quantification and was unable to identify wear progression in most cases.     

面部解剖标志与上前牙宽度的相关性

通过面部解剖标志预测上前牙宽度是目前较为普遍的一种方法。与上前牙相关面部解剖标志包括鼻翼宽度、瞳孔间距、口角间距、内眦间距等。面部解剖标志的测量方法简便并具有一定稳定性、可靠性,可将其用于指导人工上前牙宽度选择和美观参考。但面部解剖标志受性别等因素的影响,因此使用面部解剖标志预测前牙时需结合多种因素共同预测。本文就面部解剖标志与上前牙宽度的相关性作一综述。     

上颌前牙牙周附着水平与牙齿振动频率相关性的研究

目的:通过测量不同牙周附着丧失水平上颌前牙的振动频率,分析牙周附着水平与振动频率的关系,探讨牙齿振动频率作为评价牙齿松动度和牙周组织健康状况指标的可行性。方法:采用微型加速度传感器测定牙齿在牙槽窝内发生振动时的加速度变化,通过傅里叶变化将采集的随时间变化的加速度波型转变为振幅与频率之间的关系。对照图谱中的峰值,确定受试牙的振动频率,通过方差分析比较不同牙周附着丧失水平牙齿之间振动频率的差异,以相关分析确定上颌前牙牙周附着丧失水平与振动频率的关系。结果:共测定牙周附着水平不同的4组上颌前牙262个,牙周附着水平分别为0～1 mm、2～3 mm、4～5 mm、6 mm以上,相应的振动频率为(904.57±39.31)Hz、(761.14±29.10)Hz、(513.35±50.13)Hz、(335.29±67.89)Hz,不同牙周附着水平牙齿之间的振动频率值存在统计学差异(P<0.01),并且随着牙周附着水平的降低振动频率值逐渐降低。结论:随着牙周附着丧失的增加,牙齿振动频率逐渐越小。以测定牙齿振动频率作为参考指标来反映牙齿组织健康状况具一定的可行性。     

不备牙瓷贴面修复前牙切端缺损的临床效果评价

目的 评价不备牙瓷贴面修复前牙切端缺损的临床效果.方法 60颗前牙切端缺损的患者分为2组,每组30例,分别用不备牙瓷贴面和传统备牙瓷贴面进行修复,修复后用视觉模拟评分法对患者满意度进行评价,采用两独立样本t检验对两组满意度进行统计学分析.修复后1年复查,评价修复体完整度、边缘适合性、牙龈健康状况、术后敏感及颜色匹配情况,采用卡方检验对评价结果进行统计学分析.结果 不备牙瓷贴面组患者对修复体美学效果的满意度评分为(9.3±0.5)分,传统备牙瓷贴面组为(9.5±0.3)分,两组差异无统计学意义(P＞0.05).修复后1年不备牙瓷贴面组在术后敏感症状评价上优于传统备牙贴面组(P＜0.05),修复体完整度、边缘适合性、牙龈健康状况及颜色匹配上2组差异无统计学意义.结论 在严格选择适应证的前提下,不备牙瓷贴面修复前牙切端缺损的临床效果良好.     

Effects on dental health of spacing of teeth in anterior segments

Abstract The purpose of the study was to examine the relationship between spacing and dental health in 15-year-old adolecents. The whole sample consisted of 156 subjects. Out of them, 74 females and 73 males with 6 anterior teeth made up the study group for examination of the upper jaw. 75 females and 75 males had 6 anterior teeth in the lower jaw and made up the study group for examination of the lower jaw. The Plaque Index (PII) and the Gingival Index (GI) were recorded. Probing depths (PD) were measured as explained by Glavind & Løe. Filled surfaces (FS) were taken from the individual ease sheets and controlled clinically. The spacing of the individuals was assessed by counting the number of proximal surfaces without visible contact with the adjacent proximal surfaces, on model casts. The sum of proximal surfaces without contact made up the Space Index (SpI) of the individual jaw. Parametric and non-parametric statistical methods were used to analyze the data. In both sexes and both jaws proximal surfaces without interdental contact had a more favourable periodontal condition than surfaces with contact. In the upper jaw of both sexes, proximal surfaces without interdental contact had a reduced number of filled surfaces compared to surfaces with contact. The linear relationship between SpI and FS was significant, i.e., an increased number of surfaces without contact was accompanied by a reduced number of filled surfaces. In the lower jaw, the differences between the SpI groups and the linear relationship between SpI and FS did not reach significance. In both sexes and both jaws, proximal surfaces without fillings had a more favourable periodontal state compared to surfaces with fillings. Indications are that the summation effect of the presence of interdental contact and the presence of fillings contributed to the differences in periodontal condition between surfaces with and without interdental contact.     

Re-examination of incisal tooth wear in children and adolescents

summary The material presented in this report was derived from a longitudinal study of the development and progress of incisal tooth wear in children and adolescents. The study group was established in 1991–1992 (baseline examination) and consisted of participants between 8 and 15 years of age. They were re-examined in 1993 (interim examination) and in 1994 (final examination). In all, 77 school children (3O females and 47 males) participated in the three examinations. The timespan between baseline and interim was on average 15 months and the period between interim and final examination averaged 16 months. The total observation period was approximately 32 months. Assessments of incisal wear was made on stone casts using the incisal wear index which was shown to have good reproducibility. The results demonstrated that the prevalence and severity of incisal wear had increased significantly with age. In general the rate of incisal wear progression was higher between baseline and interim than between interim and final examination. In this respect certain differences between the tooth types seemed to exist. At baseline the relationship between age and incisal wear was positive and statistically significant for all tooth types. At the final examination the strength of this relationship had decreased for maxillary and mandibular central and lateral incisors. For canine teeth of both jaws the relationship between age and incisal wear was no longer statistically significant at the final examination.     

氧化锆陶瓷固位钉用于修复前牙切角缺损的临床观察

目的 探讨自行研制的氧化锆陶瓷固位钉用于前牙切角缺损修复的疗效。方法 选择临床前牙切角缺损病例80例,其中活髓牙36例,死髓牙已行根管治疗44例,随机分为两组,每组40例,实验组采用CAD/CAM氧化锆陶瓷固位钉加树脂联合修复,对照组采用树脂直接充填修复,定期随访,观察其临床修复效果。结果 1年随访,实验组成功36例,失败3例,失访1例,成功率92.3%;对照组成功20例,失败18例,失访2例,成功率52.6%。两组之间比较有显著性差异(P<0.01)。结论 在切角缺损修复过程中,氧化锆陶瓷固位钉可明显增强复合树脂的固位,是一种新型牙本质固位钉。     

Effects of malalignment of teeth in the anterior segments on plaque accumulation

The importance of malposition of teeth and plaque accumulation is still not established. The purpose of this study was to measure plaque accumulation on individual malpositioned teeth for comparison with contralateral nonmalpositioned teeth. Furthermore, the distribution of plaque in the anterior segments was measured and compared between aligned and nonaligned segments and the total mouth plaque score. Plaque scores and contact point indices were recorded from a total of 87 subjects of which 20 were drawn from dental and ancillary students and 67 from randomly chosen patients. For anterior teeth, in both groups significantly more plaque accumulated on malpositioned teeth compared with contralateral nonmalpositioned teeth. For the right-handed subjects (83), mean plaque scores for malpositioned teeth were greater than for nonmalpositioned teeth whether the malpositioned tooth was on the right or left of the anterior segment. This difference was significant in the patient group. The contact point index of the anterior segments correlated only with plaque accumulation in those subjects with a plaque index of less than 1. Upper and lower anterior segment plaque scores correlated with total mouth scores in both groups. However, the upper anterior segment scores had significantly less plaque than the total mouth score irrespective of the presence or absence of tooth malalignment, whereas the lower anterior segment always had significantly higher plaque scores than the total mouth score, irrespective of the presence or absence of malalignment. Finally, lower segments, whether aligned or malaligned, had significantly more plaque than upper anterior segments which were aligned or malaligned.