老年人牙髓感觉功能昼夜节律性变化的研究

目的:探索老年人牙髓感觉功能的昼夜生物节律,丰富牙髓时间生物学的理论基础,并指导老年牙髓病的临床诊断与治疗.方法:20位健康老年受试者,其中男性10人,女性10人.用NEOSONOUltima EZTM牙髓活力测定仪于第一天的8:00,至次日清晨8:00每隔4小时的7个时间点测试并记录牙髓活力阈值,测试结果取平均值.结果:每位受试者24小时牙髓活力阈值数据由Halberg余弦节律分析法统计分析,差异有意义(P＜0.05);老年男性女性受试者中值、振幅及相位的差异无显著性(P＞0.05).结论:老年人牙髓感觉功能具有昼夜节律性变化,活力阈值的最高峰和最低谷分别出现在0:00与12:00,即0:00时分牙髓感觉最迟钝,12:00时分牙髓感觉最敏感.     

骨性Ⅱ类前牙开牙合不同垂直骨面型磨牙高度与切牙代偿的研究

目的：比较骨性Ⅱ类前牙开牙合患者不同垂直骨面型磨牙高度及切牙代偿的差异。方法：选择40例骨性Ⅱ类前牙开牙合及20例成年正常牙合为研究对象,根据SN／MP角和FH／MP角将开牙合患者分为高角开牙合组（23例）和均角开牙合组（17例）,比较高角、均角开牙合与正常牙合对照组之间磨牙高度及切牙代偿情况。结果：①、前牙开牙合组磨牙高度均大于正常牙合组（P＜0．01）。②、高角开牙合组下颌磨牙高度大于均角组（P＜0．05）。③、高角组上切牙唇向倾斜度小于均角开牙合组（P＜0．05）。④、均角开牙合组下切牙唇倾度大于高角组（P＜0．01）。结论：不同垂直骨面型骨性Ⅱ类前牙开牙合患者磨牙高度代偿过度及上下切牙唇舌向代偿有差异,矫治中应结合不同垂直骨面型磨牙高度和切牙代偿情况,明确去代偿或代偿潜力。     

应用牙髓切断术与牙髓摘除术治疗深龋机械性露髓乳磨牙的临床效果对比研究

 目的　对比研究应用矿物三氧化物凝聚体（mineral trioxide aggragate，MTA）牙髓切断术与Vitapex牙髓摘除术治疗深龋机械性露髓乳磨牙的临床效果。方法　选取2014年6—12月于第四军医大学口腔医院就诊并符合纳入标准的深龋患儿108例，共计患牙224颗。将所有患儿随机均分为牙髓切断组（119颗患牙）和牙髓摘除组（105颗患牙），分别采用MTA牙髓切断术和Vitapex牙髓摘除术进行治疗。术后6、12、18个月随访观察两组治疗效果，并进行治疗成功率评价。结果　随访患者共92例，共计患牙192颗，其中牙髓切断组患牙101颗，牙髓摘除组患牙91颗。术后6、12、18个月牙髓切断组治疗效果均优于牙髓摘除组；比较术后18个月两组治疗成功率发现，牙髓切断组治疗成功率（90.10%）高于牙髓摘除组（79.12%），差异有统计学意义（χ2 = 4.50，P = 0.04）。结论　相较于Vitapex牙髓摘除术，MTA牙髓切断术治疗深龋机械性露髓乳磨牙的短期疗效更好，推荐临床医生应用。     

严重缺牙患者的颅面结构及软组织外形

本研究比较颅面结构与软组织的外形。将患者分为轻度缺牙组（组I：先天性缺2～5颗牙考，43例），中度缺牙组（组I：先天性缺6～9颗牙者，15例）及重度缺牙组（组回：先天性缺10颗以上牙者，29例）。对照组为无缺牙及正常股者（SO例）。平均年龄约12岁。组1中最常见缺牙为下颌第二前磨牙，其次为上颌第二磨牙及上侧切牙。但在严重缺牙组，则第二磨牙缺失的发生率随缺牙的严重程度增加而降低。在中度缺牙组则无恒定的缺牙模式，其与轻度缺牙组的遗传机制不同。随着缺牙程度加重，可观察到切牙明显的后倾及切牙间角增加，同时伴有唇突度减少…     

乳磨牙硫酸铁牙髓切断术临床疗效观察

目的：探讨硫酸铁溶液作为儿童磨牙牙髓切断术药物的可行性。方法：选择3-5岁儿童的第一乳磨牙、4～6岁儿童的第二乳磨牙共45人，80颗乳磨牙深龋近髓的病例，随机分为两组，分别行甲醛甲酚（FC）和硫酸铁溶液牙髓切断，术后6个月及1年复查，分别统计两组成功率，比较两组的疗效差异。结果：FC组和硫酸铁溶液组6月及1年的成功率无显著性差异（P〉0．05）。结论：从临床疗效看硫酸铁溶液是一种较好的牙髓切断药物。     

无托槽隐形矫治器设计平面导板对上牙列牙齿移动的影响

目的 探讨无托槽隐形矫治器设计平面导板,对上中切牙压低效率的影响及支抗前磨牙、磨牙的变化,以期对无托槽隐形矫治器设计平面导板矫治深覆(牙合)提供参考.方法 分别选取无托槽隐形矫治器设计平面导板和无平面导板矫治深覆(牙合)的病例各6例,两组均设计上中切牙不少于0.7mm的压低,通过前牙压低矫正深覆(牙合).前磨牙及磨牙作为支抗牙不设计移动.以腭穹窿为参照,重叠设计压低前后的数字化模型,比较两组上颌中切牙压低效率的差异,以及两组支抗前磨牙和磨牙的差异.结果 平面导板组上中切牙压低效率为33％,无平面导板组上中切牙压低效率为8％,二者的差异无统计学意义(P＞0.05);平面导板组第一前磨牙、第二前磨牙、第一磨牙和第二磨牙分别伸长0.3、0.1、0.2和0.1mm;无平面导板组第一前磨牙、第二前磨牙、第一磨牙和第二磨牙分别压低0.0、0.2、0.1和0.1mm,两组的差异均有统计学意义(P＜0.05);平面导板组和无平面导板组未设计移动的第一磨牙分别颊倾0.0mm和0.3mm,二者的差异有统计学意义(P＜0.05).结论 无托槽隐形矫治器设计平面导板对上颌中切牙的压低无明显影响,但能有效伸长支抗前磨牙及磨牙,克服无托槽隐形矫治器"(牙合)垫效应"造成的后牙压低,并维持磨牙水平向的位置,对深覆(牙合)的矫正发挥一定作用.     

Protaper手动镍钛锉对老年人磨牙根管治疗期间急症发生率的影响

目的：评价ProTaper手动镍钛锉对老年人磨牙根管预备术后，根管治疗期间急症（EIAE）发生率的影响。方法：临床选取老年人磨牙108个，随机分为2组，分别采用ProTaper手动镍钛锉（实验组）和手动不锈钢K锉（对照组）进行根管预备，比较2组根管预备后，患牙EIAE发生的情况。结果：实验组在老年人磨牙根管预备后EIAE发生率为14．29％，对照组为32．69％，2组间差异有显著性（P〈0．05）。结论：应用ProTaper手动镍钛锉预备老年人磨牙根管，能够显著降低EIAE的发生。     

向后牵引大鼠下颌髁突内源性cAMP含量的昼夜变化规律

本研究选用72周龄Wistar大鼠随机等量分为对照组，白天12小时加力组和夜晚12小时加力组。用放射免疫法测定髁突内源性cAMP含量并用余弦法对所得数据进行分析，结果发现：大鼠自然状态下,髁突内源性cAMP存在昼夜节律变化，调整中值112．17pmol／g，振幅12．00pmol／g，峰值相位3：32；白天加力和夜晚加力组，cAMP的昼夜节律并未消失，整条曲线垂直上移，并且白天加力组cAMP调整中值上升大于夜晚加力组。从而得到以下结果和推论：髁突改建程度，昼夜并非均匀一致，而是呈现有规律的波动；在生长发育期，于一昼夜内大鼠髁突生长的峰值期加力，即白天加力能获得最佳矫治效果，最优矫治效率，本研究结果提示，在临床早期矫形治疗中，可选择矫治的最佳介入时间来缩短疗程，提高矫治效率，即对人类采用夜间（人与大鼠昼夜节律相位差12小时）戴用矫治器可能起到同样的治疗效果。     

犬实验性牙髓炎的血流定量研究

目的 :为进一步认识牙髓炎的微循环变化机制而检测犬实验性急、慢性牙髓炎时的牙髓血流量 (PBF)。方法 :采用放射性生物微球技术 ,测量并计算犬牙髓组织的PBF值。结果 :①在急性牙髓炎期 ,切牙、尖牙和第一磨牙PBF均值分别为 1.15、1.0 9和 1.13(mL/min·g-1) ,三者间差异无显著性 (P >0 .0 5 ) ,各牙位急性期的PBF值明显高于正常及慢性牙髓炎 (P <0 .0 1)。②在慢性牙髓炎期 ,切牙、尖牙和第一磨牙的PBF均值分别为 0 .5 4、0 .79和 0 .85 (mL/min·g-1) ,此时切牙的PBF值明显小于尖牙及第一磨牙 (P <0 .0 1) ,后两者间差别无显著性 (P >0 .0 5 ) ,同正常值比较尖牙与磨牙的PBF值较高 (P <0 .0 1) ,而切牙明显低于正常值(P <0 .0 5 )。结论 :牙髓在急、慢性炎症期血流量较正常时明显升高 ,急性期上升幅度显著大于慢性期 ,而慢性牙髓炎切牙的血流量却低于正常值 ,这可能与牙髓组织发生渐进性坏死及血流测量时机的选择有关。     

应用牙髓切断术与牙髓摘除术治疗深龋机械性露髓乳磨牙的临床效果对比研究

目的　对比研究应用矿物三氧化物凝聚体（mineral trioxide aggragate,MTA）牙髓切断术与Vitapex牙髓摘除术治疗深龋机械性露髓乳磨牙的临床效果。方法　选取2014年6—12月于第四军医大学口腔医院就诊并符合纳入标准的深龋患儿108例,共计患牙224颗。将所有患儿随机均分为牙髓切断组（119颗患牙）和牙髓摘除组（105颗患牙）,分别采用MTA牙髓切断术和Vitapex牙髓摘除术进行治疗。术后6、12、18个月随访观察两组治疗效果,并进行治疗成功率评价。结果　随访患者共92例,共计患牙192颗,其中牙髓切断组患牙101颗,牙髓摘除组患牙91颗。术后6、12、18个月牙髓切断组治疗效果均优于牙髓摘除组;比较术后18个月两组治疗成功率发现,牙髓切断组治疗成功率（90.10%）高于牙髓摘除组（79.12%）,差异有统计学意义（χ2 = 4.50,P = 0.04）。结论　相较于Vitapex牙髓摘除术,MTA牙髓切断术治疗深龋机械性露髓乳磨牙的短期疗效更好,推荐临床医生应用。     

Pulp sensibility to electric stimuli in the Caucasian population

The aim of the study was to determine electric sensibility of the pulp in the Caucasian population depending on tooth morphotype, age and sex. Dental pulp sensibility was determined in 279 patients (2640 teeth). The study group consisted of 226 patients (1296 teeth), 110 men and 116 women aged 55–101. The control group consisted of 53 patients (1344 teeth), 23 men and 30 women aged 20–30. A statistically significant lower sensory threshold and increased pulp sensibility in the study group were noted. These affected the lower incisors, the second upper premolars and the first and second upper molar. The differences in the pulp sensibility were found in the region of maxillary central incisors, maxillary premolars, mandibular lateral incisors and mandibular premolars. The pulp sensibility threshold was lower for the aforementioned groups of teeth in the study group. The correlation between sensibility of the pulp and sex was not confirmed.     

Age-related and 224Ra-induced abnormalities in the teeth of male mice

A high incidence of incisor abnormalities was found in aged control and aged 224Ra-treated male CBA mice. Visual examination of the abnormalities in both controls and treated mice revealed extreme shortening of the upper incisors and hypoplastic, grooved or undulating enamel. The administration of 865 or 1730 nCi of 224Ra hastened the onset of incisor abnormalities although no specific feature was attributable solely to radium toxicity. Radiography and histology revealed corrugated incisors, obliteration of the pulp cavity, extension and disorganized growth of incisors basally, secondary incisors, open pulp and fractures within the alveoli. There was a statistically-significant reduction in the number of molars present in animals given 432, 865 or 1730 nCi 224Ra.     

A rare case of multiple talon cusps in three siblings

Talon cusp is an uncommon anomaly, whose etiology may be disturbances in the morphodifferentiation stage. Dens in dente is also a rare anomaly that is challenging in clinic as it may cause pulp necrosis or periapical lesions due to the communication with the oral cavity. This article reports multiple talon cusps on permanent maxillary and mandibular incisors and molars in 3 siblings. A 9-year-old boy presented with structures like nodules, shaped as cylindrical cones with a sharp point or a raindrop with deep developmental fissures on the palatal aspect of the maxillary central incisors, lingual aspect of the mandibular central incisors and labial aspect of both mandibular first molars. The buccal surface of the maxillary right central incisor was also affected. Some of them exhibited dens in dente. His 15-year-old sister had prominent talon cusps on the palatal surface of maxillary central incisors and buccal surface of the mandibular first molars and mandibular left second molar. His 7-year-old brother had only one trace talon on the maxillary left central incisor. No syndrome was identified in the patients. In conclusion, genetic inheritance may be a causative factor in talon cusp.     

Comparison of anterior retraction and anchorage control between en masse retraction and two-step retraction: A randomized prospective clinical trial

Objectives:The purpose of this two-arm parallel trial was to compare en masse (ER) and two-step retraction (TSR) during space closure.Materials and Methods:Forty-eight adult patients with bimaxillary protrusion who were planned for treatment with extraction of four first premolars were enrolled. All patients were randomly allocated in a 1:1 ratio to either the ER (n = 24) group or the TSR (n = 24) group. The main outcome was the amount of posterior anchorage loss in the molars and the retraction of the incisors between ER and TSR; the difference in incisor and molar inclination was a secondary outcome. Lateral cephalometric radiographs and oblique cephalometric radiographs at 45° were taken before retraction (T1) and after space closure (T2). Cephalograms were digitized and superimposed on the anatomic best fit of the maxilla and mandible by one operator who was blinded to the treatment group.Results:Neither incisor nor molar crown movements showed any significant differences between the ER and TSR. There were no significant differences in the tipping of incisors and molars between the two groups.Conclusions:No significant differences existed in the amount of retraction of incisors and anchorage loss of molars between ER and TSR. Changes in incisor and molar tipping were similar, with the crowns showing more movement than the apex.     

Early-onset periodontitis: radiographic patterns of alveolar bone loss in 55 cases from a selected Malaysian population

The objective of this report was to determine the radiographic patterns of alveolar bone loss in early-onset periodontitis (EOP) cases in a selected Malaysian population. The radiographs of 55 cases of EOP patients were examined and the radiographic patterns were classified as follows: Type I: bone destruction on first molars and/or incisors only; Type II: bone destruction on first molars and/or incisors and several additional teeth (less than 14 teeth); Type III: generalized bone destruction (greater than 14 teeth), but with involvement noticeably more extensive on the first molars and/or incisors; Type IV: generalized bone destruction (greater than 14 teeth), but with no more bone loss on the first molars and/or incisors than on other involved teeth. Sex, age, and missing teeth were also recorded. Out of 55 cases, 47 cases, 22 males and 25 females, were classified into the types mentioned above; the remaining 8 cases were excluded due to too many missing teeth. It was found that 7 (14.9%) were Type I; 12 (25.5%) were Type II; 7 (14.9%) were Type III; and 21 (44.7%) were Type IV. There was a predominance of first molar/incisor involvement in Types I, II, and III with the maxillary first molars most frequently involved followed by the mandibular central incisors. Type I occurred in the younger age group and Types II, III, and IV mainly in the older age group. It was concluded that EOP in this patient sample resembled that of western society.     

A Prospective,Randomized, Double-blind Comparison of 2% Lidocaine With 1:100,000 and 1:50,000 Epinephrine and 3% Mepivacaine for Maxillary Infiltrations

IntroductionThe purpose of this prospective, randomized, double-blind crossover study was to evaluate the anesthetic efficacy of 2% lidocaine with 1:100,000 and 1:50,000 epinephrine and 3% mepivacaine in maxillary lateral incisors and first molars.MethodsSixty subjects randomly received, in a double-blind manner, maxillary lateral incisor and first molar infiltrations of 1.8 mL of 2% lidocaine with 1:100,000 epinephrine, 2% lidocaine with 1:50,000 epinephrine, and 3% mepivacaine at three separate appointments spaced at least 1 week apart. The teeth were pulp tested in 3-minute cycles for a total of 60 minutes.Results and ConclusionsAnesthetic success and the onset of pulpal anesthesia were not significantly different between 2% lidocaine with either 1:100,000 or 1:50,000 epinephrine and 3% mepivacaine for the lateral incisor and first molar. Increasing the epinephrine concentration from 1:100,000 to 1:50,000 in a 2% lidocaine formulation significantly decreased pulpal anesthesia of short duration for the lateral incisor but not the first molar. For both the lateral incisor and first molar, 3% mepivacaine significantly increased pulpal anesthesia of short duration compared with 2% lidocaine with either 1:100,000 or 1:50,000 epinephrine.     

Comparison of achieved and predicted tooth movement of maxillary first molars and central incisors: First premolar extraction treatment with Invisalign

Objectives:To compare achieved and predicted tooth movements of maxillary first molars and central incisors in first premolar extraction cases treated with Invisalign.Materials and Methods:The present study included 30 patients who received maxillary first premolar extraction treatment with Invisalign. The actual posttreatment model was registered with the pretreatment model on the palatal stable region and superimposed with the virtual posttreatment model. Achieved and predicted tooth movements of maxillary first molars and central incisors were compared using paired t-test. Linear mixed-effect model analyses were used to explore the influence of age (adolescents vs adults), attachment (G6-optimized vs 3-mm vertical, 3-mm horizontal, and 5-mm horizontal), and initial crowding on the differences between predicted and achieved tooth movement (DPATM).Results:First molars achieved greater mesial tipping, mesial translation, and intrusion than predicted. Central incisors achieved less retraction and greater lingual crown torque and extrusion than predicted. Adolescents showed greater DPATM in the mesiodistal translation of first molars and labiolingual translation of central incisors and smaller DPATM in the occlusogingival translation of the first molars and crown torque of the central incisors than adults. The 3-mm vertical attachment group showed greater DPATM in the mesiodistal translation of the first molars vs the G6-optimized attachment group. Initial crowding had an inverse correlation with DPATM in angulation and mesiodistal translation of the first molars.Conclusions:First molar anchorage control and central incisor retraction were not fully achieved as predicted in first premolar extraction treatment with Invisalign. Age, attachment, and initial crowding affected the differences between predicted and achieved tooth movement.     

Effect of sample thickness on bite force studied with a multiple-point sheet sensor

The aim of this study was to investigate the relationship between thickness of sample food and bite force. We designed a new sensor that can detect the pressure distribution between the incisor and molar teeth on one side, and the contact area between the food samples and the teeth. The force and contact area were directly measured in real time using the multiple-point sheet sensor, which is a very thin and flexible pressure-sensing device. Silicone rubber blocks were used as a sample food and were chewed with incisors and molars by 10 healthy women. The peak force, contact area, duration and impulse were greater between the incisors for a thicker specimen. The active pressure, defined as the ratio of the force to contact area, at peak was similar for different thicknesses. In contrast, with a 2 mm thick sample, the peak force and force related parameters were greatest in molar chewing. The force, contact area and duration were greater for molar chewing cycles than incisor ones. We verified that the thickness of samples influenced the chewing force of humans and the effects differed between incisors and molars.     

Anesthetic efficacy of 1.8 mL and 3.6 mL of 2% lidocaine with 1:100,000 epinephrine for maxillary infiltrations

The purpose of this prospective, randomized, single-blinded study was to measure the degree of anesthesia obtained with 1.8 mL and 3.6 mL of 2% lidocaine with 1:100,000 epinephrine in maxillary infiltrations. Ninety-six adult subjects randomly received infiltrations of 1.8 mL and 3.6 mL of the lidocaine solution at two separate appointments, in a crossover design. Thirty-two lateral incisors, 32 first premolars and 32 first molars were studied in this investigation. Anesthetic success (obtaining two consecutive 80 readings with the electric pulp tester) for the two volumes ranged from 97% to 100%. The onset of pulpal anesthesia was not statistically different between the two volumes. For both volumes, the lateral incisors had a higher percentage of anesthesia of short duration than the first premolar and first molar. The 3.6 mL volume provided a statistically longer duration of pulpal anesthesia for the lateral incisor, first premolar, and first molar.