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。     

Transpositions of maxillary teeth

Transposition of teeth is a rare and special type of ectopic eruption where two contiguous teeth are found occupying each other's respective normal positions. Nine patients with transposed maxillary teeth are reported. The literature on transpositions, especially on the theories regarding the aetiology, is reviewed.     

Attitudes of Central Collegiate Hockey Association ice hockey players toward athletic mouthguard usage

OBJECTIVE: The purpose of this study was to examine Central Collegiate Hockey Association ice hockey players' attitudes regarding the use of athletic mouthguards and to determine the effects of mouthguard type, player position, education, and usage time with respect to attitudes. METHODS: A questionnaire measuring players' attitudes toward mouthguards was sent to certified athletic trainers (ATC) responsible for providing healthcare coverage at 10 institutions of the Central Collegiate Hockey Association (CCHA). The ATC's distributed the surveys to all the players on their respective collegiate teams. Out of a total of 265 players listed on the roosters of the CCHA, one hundred and sixty five (62%) players returned the surveys, with 158 surveys used in the analyses (60%). RESULTS: Approximately 13.3% of players (n=21) reported wearing mouthguards 50% of the time or greater during games and 3.8% (n=6) reported wearing mouthguards 50% of the time or greater during practices. Twenty-six percent (n=41) of the players never received educational information regarding using mouthguards. Thirty-nine percent (n=59) of the players reported altering mouthguards to obtain a better fit while 91% of the players were not influenced by the cost of the mouthguard. A 2 x 2 x 2 ANOVA revealed a significant interaction among player position and mouthguard type with respect to player attitudes (F(1,131) = 4.96, P < 0.05), with defensive players having more negative attitudes toward mouthguard usage compared to offensive players. CONCLUSION: No one specific factor affecting attitudes was identified, however, players reported limited educational opportunities to learn about the effectiveness of mouthguards. Therefore, coaches, dentists, and healthcare providers should engage in more preventive educational programs to increase player attitudes and compliance.     

792个活体前牙色度学分析

目的：研究人活体前牙色度学分布。方法：采用数码照像计算机色度分析系统采集、分析132例受试者上前牙色度值及Vita比色板各色片的色度值。结果：正常人前牙色度值范围为L^＊ 62．64-81．24、a^＊ 4．67-11．74、b^＊ 14．45～24．09，上中切牙亮度值（L^＊值）最大，侧切牙次之，尖牙亮度值最小，上中切牙彩度值（a^＊和b^＊值）最小，侧切牙次之，尖牙彩度值最大，Vita比色板的色度值范围为L^＊ 62．09-73．41、a^＊ 0.67～2．74、b^＊ 8．09～18．08。结论：正常人前牙色度分布具有规律性，Vita比色板的色度值范围与正常人前牙色度值范围不匹配。     

Pulp test response of the maxillary anterior teeth in cleft palate patients

The relative pulpal responsiveness of the six maxillary incisors to electrical and cold thermal stimuli was tested in patients with complete unilateral and bilateral clefts. The six maxillary anterior teeth were tested at random to electrical stimuli. After a 5-minute interval, the same teeth were tested at random to cold stimuli with an ice pencil. Unilateral and bilateral cleft palate patients had statistically significant higher mean electrical pulp test thresholds for the maxillary anterior teeth than the noncleft palate patients. No statistically significant difference between unilateral and bilateral cleft palate patients was found in electric pulp test responses of the maxillary anterior teeth. No statistically differences in electric pulp test responses and cold test responses of the maxillary anterior teeth in both cleft palate and noncleft palate individuals based on differences in sex were observed. No statistically significant difference in cold test responses were observed between cleft palate and noncleft palate patients. Cleft palate patients who completed orthodontic treatment within 1 year of testing showed elevated mean electrical pulp test thresholds as did noncleft palate patients who received orthodontic treatment within 1 year of testing.     

不同厚度、不同材质护齿膜片能量吸收特性分析

目的 利用冲击试验测试不同厚度、不同材质的护齿膜片吸收能量的性能。方法 1-4、7号膜片分别为BIOPLAST 5、4、3、2、1 mm的软质膜片,5号膜片为ERKOLOC-PRO 2 mm的软硬结合膜片,6号膜片为DURAN 2 mm的硬质膜片。冲击压头从不同高度冲击膜片,利用高速摄像采集系统,拍摄冲击压头下落、压入膜片以及回弹的过程,将图像传输至软件进行数据处理,获得冲击压头的入射速度、入射深度及回弹高度。计算膜片碰撞过程中吸收的能量和吸收能量比,反映不同护齿膜片吸收能量的性能。采用SPSS 22.0软件包中的单因素方差分析及最小显著性差异法,分析不同组别之间的差异。结果 冲击压头下落高度越高,碰撞过程中护齿膜片的能量吸收比越大。软质护齿膜片中,1、2、3、4、7号膜片平均吸收能量比有显著差异（P<0.05）;其中,7号1 mm膜片碰撞过程中平均吸收能量比最大,为（77.98±2.19）%。对于2 mm不同材质的护齿膜片,4、5、6号膜片平均吸收能量比有显著差异（P<0.05）;其中,软质膜片和软硬结合膜片的能量吸收比较大,硬质膜片最小。结论 3 mm护齿膜片的吸收能量性能不亚于4、5 mm膜片,其性能足够支持其用于制作运动护齿,且具有轻薄舒适的优势。软质和软硬结合膜片相比于硬质膜片,更适合用于制作运动护齿。     

The effect of altering jaw position on the transmission of vibration between the skull and teeth in humans.

The forces that develop in the human temporomandibular joint during function have never been directly measured, yet many patients exhibit excessive localized wear and tear of the joint, suggesting that at times these forces exceed tissue tolerance. The purpose here was to gain insight into vibration transmission between the cranium and mandible in healthy humans during variations of jaw position. In 13 normal healthy adult men (age 25-40 years) with normal dentitions, vibration (around 400 Hz, sine wave) was applied to the skull vertex and changes in the intensity of the vibration signal were measured using several small linear accelerometers cemented to the buccal surfaces of mandibular first molars and the labial surfaces of maxillary central incisors. The jaw was opened, protruded and moved laterally by the individual participant and vibration signal intensities were tested (lower first molar signal/upper incisor signal) for change at each mandibular position by ANOVA. The results showed the vibration signal changed significantly with opening and less so on protrusion and laterotrusion. The vibration signal during opening could be categorized into three types: (1) signal increased continuously with increased opening; (2) signal increased, then reached a plateau during last third of opening; (3) signal increased, then decreased when the individual moved from 40 mm to maximum opening. These findings show that as the jaw moves laterally, and especially as it opens, the magnitude of the vibration signal increases substantially compared with the near-closed position.     

Location of centres of resistance for maxillary anterior teeth measured on human autopsy material.

The location of the centre of resistance (CR) of various consolidated units of maxillary anterior teeth was determined in this study using human autopsy material. The units studied consisted of two central incisors, four incisors, and six anterior teeth. When horizontal forces were applied the CR for the two- and six-tooth units was located approximately 6.5 mm apical to the bracket position. For the four-tooth unit, CR was placed slightly more occlusally, the distance being 5.0 mm. Applying vertical forces CR was located about 13.0 mm posterior to the bracket position for the two- and four-tooth unit. The incorporation of the canines into the incisor segment resulted in a distal shift of CR of 6 mm. CR for the six anterior teeth was, thus, located on a line 3 mm behind the distal surface of the canines. Increasing force levels had little effect on the location of CR for a given unit.     

上颌后牙缺失患者上颌窦影像学特征分析

目的：分析上颌后牙缺失患者的上颌窦影像学特征,探讨不同类型上颌后牙缺失患者上颌窦影像学的变化特点。方法：选取上颌后牙缺失患者的700份数字化X线曲面断层片作为研究资料。调查上颌窦分隔和上颌窦囊肿的发生率并根据患者的性别,年龄及缺牙状况进行分组,测量各组缺牙区的窦嵴距及窦底高度,使用SPSS16.0软件对数据进行统计学分析。结果：单牙缺失组窦嵴距〉多牙缺失组窦嵴距,两组之间差异有显著性（P〈0.001）。多牙缺失组窦底高度〉单牙缺失组窦底高度,两组之间差异有显著性（P=0.014）。59岁～77岁组女性窦嵴距〈男性窦嵴距,男性窦低高度〈女性窦低高度,组内比较有显著差异（P〈0.001）。上颌窦分隔发生率为27%,上颌窦囊肿发生率为4.9%。结论：上颌后牙缺失不同缺牙状况窦底高度和窦嵴距有统计学差异,59～77岁年龄段窦底高度和窦嵴距有性别差异。     

牙科锥形束CT评价上颌前牙唇面形态对转矩的影响

目的研究上颌前牙的唇面形态及牙冠牙根成角关系对转矩的影响,为临床治疗中调整牙齿的转矩提供参考。方法选择206颗离体上颌前牙为研究对象,其中中切牙77颗、侧切牙68颗、尖牙61颗。利用牙科锥形束CT将全部牙齿进行扫描,在CT工具软件下进行影像的三维重建并提取全部牙的正中矢状切面图像,利用Auto CAD软件测量图像,分别测量牙冠唇面4个不同高度的切线与牙冠长轴所成的角度,以及牙冠长轴与牙根长轴所成的角度（冠根角）。结果当托槽高度为3.5～5.0 mm时,其高度每变化0.5 mm,上颌中切牙转矩变化约为1.5°,上颌侧切牙和尖牙的转矩变化约为2°。上颌中切牙、侧切牙、尖牙冠根角的均数分别为0.88°、3.87°、-3.30°。结论牙体形态的生物学变化从多方面影响矫治后牙齿的转矩角。