22牙2根1例

患者男,30岁.因左上颌牙错位影响美观要求拔除而就诊.检查:22腭侧移位,无功能.在局麻下行22拔除术,手术困难,拔出该牙见有2个根,唇侧根较腭侧根粗大,且唇侧根根尖向腭侧弯曲,离体牙X线片见2个根管畅通.     

16四根管2例

据统计 ,上颌第一磨牙有 2 2 %近中颊根分为 2个根管 ,即 2 - 1型根管 ;14 %有 2个完全独立而清晰的根管 ,即 2 - 2型根管。由于其根管结构复杂 ,因此在根管治疗时 ,应注意寻找是否存在近中舌根管。作者在临床治疗过程中发现 16四根管 2例 ,现报道如下。病例 1　患者男 ,2 0岁。 2 0 0 1- 11因右侧上颌后牙充填物脱落来诊。检查 :16牙合面大面积龋坏 ,原充填物脱落。探 (- ) ,叩 (± ) ,无明显松动。X线片示 16未行根管治疗 ,近颊根尖有骨质稀疏区。诊断 :16慢性尖周炎。治疗 :常规去龋 ,开髓 ,清理根管及近颊、远颊、腭侧 3个根管 ,并于近…     

31牙2根1例

患者女 ,2 3岁。因左侧下颌前牙外伤 2周后疼痛就诊。检查 :3 1色黑 ,叩 ( ) ,Ⅰ度松动。诊断为急性根尖周炎。对其进行根管治疗术 ,X线示根管充填理想。术后原有症状基本消失。 3个月后患牙重新出现叩痛 ,去除原根充物 ,重新探查根管 ,发现在原治疗根的唇侧有另一根管 ,以 #1 5扩大针试探 ,可探及该根管深度 1 7mm ,根尖向舌侧弯曲 ,插入牙胶尖于两根管内 ,用不同角度拍X线片 ,证实有 2个根管 ,行根管治疗 ,封FC棉捻 ,1周复诊 ,患者自诉原有症状消失 ,根管充填后 ,观察 4周无症状。31牙2根1例@王丽华$口腔医院!山东威海264200 @黄永…     

下颌第一磨牙近中根3根管2例报告

下颌第一磨牙是最早萌出的恒牙,也是患龋率最高的恒牙,且由此导致的牙髓炎和根尖周炎需接受根管治疗的机率也很高.越来越多的临床医生意识到下颌第一磨牙根管解剖结构的多变性,并在临床工作中有意识地探查额外根管.本文报道了下颌第一磨牙近中3根管的2个病例,以期对该牙的根管治疗提供参考.     

上颌第一磨牙近中颊根MB2根管研究

目的：观测上颌第一磨牙近中颊根MB2的存在率,根管口的位置及形态。方法：采用牙体硬组织切片机对拔除的上颌第一磨牙进行连续横断切片,并在显微镜下观测其近中颊根第二根管存在情况,根管口位置及根管形态。结果：220个上颌第一磨牙中有81个存在近中颊根第二根管,存在率为36．81％,近颊根第二根管口横切面形态为圆形或卵圆形,近颊第二根管口与近颊第一根管口,远颊根管口和腭根管口的位置关系呈斜四边形。结论：上颌第一磨牙近中颊根第二根管存在率较高,其开髓形状应为斜四边形。     

上颌第一前磨牙3根2例

据资料报道，上颌第一前磨牙双根率约为87％，三根者少见。笔者于临床遇上颌第一前磨牙3根2例，现报道如下：     

上颌第一前磨牙3根2例

病例1，男，16岁，粤籍，学生。因牙列拥挤矫治拔除右上颌第一前磨牙。于1997年9月21日局麻下拔除时，手感阻力感大，经完整拔出发现该牙为3根，颊侧2根，腭侧1根，远颊根略短1mm，两颊根中部至根尖微向远中弯英。3根分叉大，酷似上颌第一磨牙（图1）。     

下颌第一双尖牙畸形根2例

作者从收集到的312颗下颌第一双尖牙中发现畸形根2例(0.64％)。其中1例唇侧颈缘有楔状缺损,牙根于根中、尖1/3交界处分出3根,近中1根、远中2根(附图a),三根分叉,成鼎脚状张开,游标卡尺测冠长7.65mm,根长14.76mm,分叉处距颈缘10.24mm,远中2根根尖间距6.05mm,距近中侧根尖3.82mm与4.92mm。体视显微镜观察每个根尖有2～3个根尖孔。 另一例在牙根舌侧颈缘处分出一细小的额外根(附图b)。额外根根长7.22mm,约为主根全长的1/2,分叉处直径1.55mm,根尖仅一个根尖孔。     

26四个根管2例

病例 1　患者男 ,38岁 ,1998- 0 6左上后牙疼痛来诊。检查 :2 6远中牙合面颈部广泛龋坏 ,探 (- ) ,叩 ( ) ,松动Ⅰ度 ,牙龈充血、压痛 ;Ｘ线片示 :2 6三个根 ,远中颊侧根尖稀疏区较大。炎症消除后 ,局麻下拔除 2 6 ,术中感觉阻力很大 ,腭侧根根尖 1/ 3处折断 ,用牙铤挺出。离体牙的远中颊侧根扁 ,根尖 1/ 3为分叉状 ,分出 2个根管 ,2根尖的连线与近远中向垂直。病例 2　患者男 ,6 5岁 ,于 1998- 11因左上后牙疼痛来诊。检查 :2 5残冠 ,叩 (- ) ,探 ( ) ,松动Ⅰ度 ;2 6近中颈部浅龋 ,探 (± ) ,叩 (- ) ,松动 0～Ⅰ度 ,伸长 ,牙龈萎缩达根颈1…     

上颌第一磨牙近颊根MB2根管治疗1例

病人男,40岁。主诉右侧上颌后牙充填物脱落1周,要求补牙而就诊。病史:2年前患牙曾做治疗,之后出现牙龈肿胀,口服抗生素缓解。临床检查:16牙冠大部缺损,髓腔开放,冷刺激痛(-),叩诊(±),松动度(-)。     

Comparison of the cutting efficiency of two ultrasonic units utilizing two different tips at two different power settings

The objective of this in vitro study was to set up a testing protocol and utilize it to evaluate and compare the cutting efficiency of ultrasonic units. Evaluation of two ultrasonic units utilizing two different tips was done by measuring the weght of a dentin specimen before and after ultrasonic treatment for set time periods. The difference in weight was the amount of dentin removed. The ultrasonic units tested were the P5 Booster (Staelec, France) and the Spartan (Obtura-Spartan, Fenton, MO) machines. The tips tested were the CPR-2D and ETD20 types. The units were tested at maximum and medium power. All the experimental variables, ultrasonic unit type, power setting and tip type were found to have an effect on the cutting efficiency (P<0.0001). The P5 ultrasonic unit was more effective at dentin removal than the Spantan ultrasonic unit at both power settings. The ETD-20 tip was more effective at dentin removal than the CPR-2D tip on both units at both power settings.     

The effectiveness of two sonic and two ultrasonic scaler tips in furcations

This study compared the effectiveness of two sonic and two ultrasonic scaler tips on artificial calculus removal from the furcations of mandibular first and second molars. Twenty-four extracted mandibular molars were cleaned and randomly assigned to one of four treatment groups. Teeth were split buccal lingually, artificial calculus was placed in the furcation areas, and the teeth were photographed with a stereo camera. Teeth were reconnected with bonding material and mounted in a typodont with simulated gingiva and attached to a dental chair. Teeth were instrumented with either a Cavitron TFI10 tip, Cavitron EWPP tip, Titan-S Universal tip, or Titan-S Sickle tip by a licensed dental hygienist until each tooth was judged calculus free to the touch with a CH3 explorer. Time for each instrumentation period was recorded. Following instrumentation, the teeth were again split and photographed. Stereophotogrammetry was used to produce tracings of the teeth with initial calculus and remaining calculus. Pre-instrumentation and post-instrumentation amounts of calculus on the surface area were computed using the Bioquant system. A two factor analysis of variance was conducted followed with a Newman-Keuls Multiple Comparison Technique to test for within and between differences. Significant differences (P less than or equal to 0.01) were found between pre- and post-amounts of calculus for all tips. No significant differences (P less than or equal to 0.05) were found between the four instrument tips with respect to percentage of furcation surface with calculus remaining. No differences were found between tips with regard to the time required to clean the test surfaces.     

Managed care--serving two masters

It is likely that enrollment in managed care dental plans will continue to increase. Dentistry can respond to this trend by resisting it; however, just as the health care marketplace drove medical care into managed care mechanisms, so too will these forces impact dentistry. For those who are participating in managed care dental plans, it is heartening that current data indicate that most types of patient care are not adversely affected by reimbursement mechanisms. Dentistry, however, should seek out opportunities to shape the managed care format and must be at the table to assure that ethical principles and conflicts of interest receive due consideration. Dentists who treat patients under a managed care reimbursement system must be certain that the plan does not require providers to sacrifice patient autonomy or compromise care in the process of serving two masters.     

Epignathus: two cases

Epignathus is a rare congenital nasopharyngeal tumour that is derived from the upper jaw, palate, and sphenoid bone. It usually protrudes through the mouth, leading to an appreciable risk of obstruction of the upper airway and death soon after birth. We report two cases of unusual presentations that illustrated some uncommon and similar characteristics. Although these tumours are not consistent in origin, number, and differentiation of tissues, both contained structures that were derived from all three layers of germ cells, including different anomalous tissues internally (dental bud, fat and muscular tissues, mucosal epithelium). Externally, they contained normal epidermis (skin with fine hairs). Imaging studies and operative findings showed that both tumours originated from the anterior portion of the sphenoid bone causing a sphenoidal sinus cleft without intracranial communication.     

Maxillary removable prostheses retained by telescopic crowns on two implants or two canines

Precision telescopic attachments allow for rigid connection between removable prostheses and abutments. However, it is still unknown whether implants can bear similar long-term loading forces as teeth when telescopic crowns are used as retention devices. It was the aim of this prospective clinical study to observe maxillary removable partial dentures that were retained by telescopic crowns on two endosseous implants in the canine regions. In a control group, identical dentures were fabricated that were retained by telescopic crowns on the maxillary canines. The implant group consisted of 14 patients, and the control group included 8 patients. Mean observation time of the prostheses was 25.6 months. Radiographic bone levels and periodontal parameters did not reveal specific differences between the two groups. However, five implants failed, and there were no failures in the control group. Survival rates were 48.9% for the implant group and 100% for the control group, with a significant difference between the two groups. Within the limits of this study, it is concluded that the telescopic connection might be too rigid (thus delivering overloading) for two single implants in the canine region of the maxilla supporting a removable denture.     

2种根管封闭剂对2种纤维桩剪切粘接强度的影响

目的 研究2种根管封闭剂对2种纤维桩固位力的影响.方法 将28颗完整离体上颌中切牙截冠、逐步后退法预备根管,按采用的根管封闭材料及纤维桩不同分为4组:Cortisomol封闭剂+Matchpost纤维桩(A组),Cortisomol封闭剂+Macrolock纤维桩(B组),Guttaflow封闭剂+Matchpost纤...