Prosthodontic Considerations in the Implant‐Supported All‐Ceramic Restoration of Congenitally Missing Maxillary Lateral Incisor: A Clinical Report

The congenitally missing maxillary lateral incisor is the most common agenesis in the anterior region. There are several treatment options for this anomaly, which causes severe deficiencies: orthodontic space closure, tooth‐supported restoration, or single‐tooth implant. Each of these solutions has a high degree of success if used in the correct situation. An implant‐supported restoration with an interdisciplinary approach provides a predictable outcome. This article describes the treatment of a patient with agenesis of the maxillary left lateral incisor. After orthodontic space management, it was decided to restore the tooth with an all‐ceramic crown cemented on a zirconia custom abutment, which fractured after only 6 weeks of service. Fractographic analysis revealed that the failure was due to over‐reduction of the buccal wall to correct the labial emergence of the implant. Zirconia abutments should be designed with even wall thicknesses of at least 0.8 mm to avoid areas that may compromise functional success.     

Correlation between Body Mass Index and the Occurrence of Postoperative Complications after Surgical Removal of the Lower Third Molar

ObjectivesSwelling, pain and trismus after the surgical removal of the mandibular third molars are the most common and expected postoperative complications. The aim of this cross-sectional study was to assess the association of those postoperative complications and BMI after surgical removal of the mandibular third molars.Material and methods84 patients who required the surgical removal of their lower third molar were enrolled in this study and were divided into 4 groups dependent on their BMI. Data were tested by one-way analysis of variance (Welch''s ANOVA). The differences were tested by the intragroup using the Games-Howell test.ResultsThe effect of BMI on pain had a statistically significant difference within the first 24 postoperative hours: 4 hours (p=0.014), 6 hours (p=0.034, p=0.049), 12 hours (p= 0.00.P=0.023), and 24 hours (p=0.010). For swelling and trismus in the exception on first postoperative day between underweight and normal weight groups (p=0.026), and underweight and overweight groups (p=0.014) no statistically significant correlation was foundConclusionBMI has an impact on a patient’s early postoperative recovery     

龈沟内环形切口法用于下颌远中邻面暴露≥1/2的水平阻生第三磨牙拔除的研究

目的 探讨龈沟内环形切口法用于下颌远中邻面暴露≥1/2的水平阻生第三磨牙拔除的临床效果。方法 纳入2020年3月—2022年3月我院收治的180例需拔除下颌远中邻面暴露≥1/2的水平阻生第三磨牙的患者作为研究对象,采用随机数字表法分为观察组和对照组,每组90例。观察组采用龈沟内环形切口法,对照组采用标准封套法。比较两组术后2、7 d出血程度、疼痛程度、肿胀程度、最大开口度,术前与术后3个月下颌第二磨牙牙周探诊深度及并发症发生情况。结果 观察组术后2 d出血程度、疼痛程度、肿胀程度均轻于对照组（P＜0.05）,最大开口度大于对照组（P＜0.05）,两组术后7 d出血程度、疼痛程度、肿胀程度、最大开口度差异均无统计学意义（P＞0.05）;两组术后3个月下颌第二磨牙远颊位点、近颊位点、颊侧位点、远舌位点、近舌位点、舌侧位点牙周探诊深度较术前差异均无统计学意义（P＞0.05）,且两组组间差异无统计学意义（P＞0.05）;两组并发症总发生率差异无统计学意义（P＞0.05）。结论 下颌远中邻面暴露≥1/2的水平阻生第三磨牙拔除术中采用龈沟内环形切口法,可减轻术后早期出血、疼痛及开口受限,缩短软组织恢复时间     

快速整体内收上颌前牙对犬牙根吸收影响的扫描电镜观察

目的研究牙槽外科辅助快速整体内收上颌前牙对实验犬前牙牙根的影响。方法建立牙槽外科辅助快速整体内收上颌前牙的比格犬动物模型后,连续加力12 d,速度0.5 mm/d,分别于加力停止并固定1 d,14 d,28 d后随机处死3只实验犬,拔出一侧上颌第三切牙,制备标本行扫描电镜观察。结果加力停止1 d及14 d后牙根吸收明显,停止加力28 d后,牙根吸收面积明显减小:牙根颈部28 d与1 d(t=25.075,P=0.014)、28 d与14 d(t=17.444,P=0.056)比较,差异有统计学意义;牙根尖部28 d与1 d(t=26.436,P=0.000)、28 d与14 d(t=18.229,P=0.003)比较,差异有统计学意义。结论牙槽外科辅助快速整体内收上颌前牙会造成一定程度的牙根吸收,随着加力停止后固定时间的延长,牙根吸收可明显修复。     

Suppression of the jaw-opening reflex by periaqueductal gray stimulation is decreased by paramedian brainstem lesions

Electrical stimulation of the midbrain periaqueductal gray region (PAG) suppresses the tooth pulp-evoked jaw-opening reflex (TP-JOR). In the present study the pathways that mediate this suppression were investigated by placing brainstem lesions in lightly anesthetized cats. Parasagittal lesions that interrupted the afferent and efferent connections of the medullary and pontine raphe nuclei attenuated (but did not abolish) suppression of the TP-JOR evoked by PAG stimulation. This result provides further evidence that medial brainstem structures partially mediate the effects of PAG stimulation in the trigeminal system.     

A customized metal guide for controllable modification of anterior teeth contour prior to minimally invasive preparation

ObjectiveOptimal tooth reduction is a key requirement for aesthetics, function, and the longevity of fixed restorations. Research has demonstrated that controlled and conservative tooth preparation is crucial for the long-term success of adhesive restorations. Different techniques of fabricating reduction guides have been previously reported in literature. The present technical note describes the fabrication technique and clinical application of a customized metal preparation reduction guide.Material and methodPatient presented with tilted maxillary left central incisor. The flared-out part of the tooth was modified prior to veneer restoration preparation. Resin pattern reduction guide was fabricated on the diagnostic cast with a window on the tilted mesial portion of the tooth. After intraoral evaluation, resin pattern guide was casted. Metal reduction guide was place intraorally and reduction was provided on the exposed surface of the tooth. After the removal of the tilted portion, a harmonious arch form allowed the clinician to provide adequate evaluation and preparation for veneer restorations.ResultsThe device demonstrated good practical value, allowing for selective and controlled reduction of tooth structure, and definitive protection of adjacent tooth surfaces from iatrogenic damage. The clinical outcome successfully addressed the patient’s restorative and aesthetic needs, and the veneer was stable 2 years postoperatively.ConclusionUse of a metal guide assists clinicians to provide a more predictable reduction of a desired tooth surface, while decreasing the risk of compromising the other/adjacent tooth surfaces.     

不同粘结剂对牙髓组织影响的动物实验研究

目的比较牙体预备2.0mm后戴用不同粘接材料粘固的临时冠1周,2周,观察牙髓组织学结构的变化及差异。方法选择BEAGLE犬的恒牙作为研究对象,在牙体预备前及预备牙体组织2.0mm后即时用不同粘接材料粘固临时冠1周和2周,制备组织切片,观察牙髓组织结构的变化及差异。结果牙体预备后即时,牙髓组织可见大量血管扩张,个别炎性细胞浸润,1周时,三种粘结剂（氧化锌、玻璃离子、聚羧酸锌）组牙髓组织见少量血管扩张,无炎性细胞浸润,2周时,三种粘结剂组牙髓组织基本正常。使用三种临时冠粘结剂,牙髓组织结构无明显差异。结论在同等备牙量条件下,三种粘结材料对牙髓组织的作用无明显差异。     

护牙素对金属烤瓷全冠基牙表面形态的影响

目的研究护牙素对金属烤瓷全冠基牙制备后牙齿表面形态的影响。方法选择临床拔除的阻生牙20颗,按照金属烤瓷全冠制备要求预备基牙后随机分为对照组和实验组,每组10颗。实验组基牙表面开窗区涂布护牙素,对照组不作其他处理,然后置于37℃蒸馏水中恒温水浴30 min。2组标本脱水干燥后,扫描电镜观察表面形态。结果扫描电镜下对照组基牙表面条纹状痕迹明显,凹凸不平,牙面呈凌乱的疏松无定形状态。实验组牙面表面痕迹较浅,见密集钙质小团的沉积覆盖牙面。结论金属烤瓷全冠的基牙预备后,使用护牙素可以改变牙齿表面微结构。     

垂直型快套附着体义齿的初步应用

目的：介绍垂直型快套附着体义齿的设计原则、制作方法，评价其疗效。方法：为12例牙列缺损成年患者制作12件垂直型快套附着体义齿，每件义齿设计1副或2副快套附着体，经6个月至2年时间的临床观察。结果：全部病例使用垂直型快套附着体义齿后，固位良好、咀嚼功能好、美观舒适。结论：垂直型快厉型附着本固位好，快套内部的弹性结合产生缓冲作用，使基牙的损伤减少。