Biomechanical effects of the implant material and implant–abutment interface in immediately loaded small-diameter implants

Objective

Small-diameter implants have been available since the 1990s, but few studies have analyzed their mechanical properties. This study evaluated the effects of the implant material and the implant–abutment connection designs on the primary stability and the marginal bone strain of small-diameter implant subject to immediate loading.

Materials and methods

Insertion torque value (ITV), implant stability quotient (ISQ), and Periotest value (PTV) of three implant systems with four parameters (titanium, titanium alloy, internal and external hexagon connections) were measured after placing implants into artificial type 2 jaw-bone models. Specimens were tested under both vertical and oblique static loads at 190 N. Peak values of the principal bone strain were recorded and analyzed statistically by the Kruskal–Wallis test and multiple-comparisons Bonferroni test.

Results

PTV and ISQ were higher for the NIOSM311 (internal-hex and Ti alloy) and FOSM311 (external-hex and pure Ti) implants, respectively, than for the NOSM311 (external-hex and Ti alloy) implant. Under vertical loading the peak value of peri-implant bone strains did not differ significantly among these three implant systems. However, the peak bone strains were at least 32 % lower for the NIOSM311 and FOSM311 implants than for the NOSM311 implant under lateral loading.

Conclusions

The implant material and the implant–abutment connection design significantly influence the peri-implant bone strain of immediately loaded small-diameter implants, but barely affect their primary stability.

Clinical Relevance

A commercially pure titanium implant with an internal connection has the potential to reduce the risk of implant failure of small-diameter implant related to biomechanical complications.     

Reconstruction of palatomaxillary defects following cancer ablation with temporalis muscle flap in medically compromised patients: a 15-year single institutional experience

Objectives

Successful reconstruction of palatomaxillary defects following cancer ablation represents a formidable challenge for surgeons to achieve consistently favorable outcomes. The purpose of this article is to present our experience in oncologic palatomaxillary repair with temporalis muscle flap (TMF) for medically compromised patients who are not ideal candidates for microvascular reconstruction at a Chinese tertiary referral hospital over a 15-year period (1998–2012).

Method

A retrospective chart review was performed to identify patients with compromised medical conditions who underwent oncologic palatomaxillary reconstruction using TMF. Patients’ demographics, clinicopathological variables, and surgical techniques were presented. Postoperative functional and aesthetic outcomes were assessed by measurements and patients self-evaluations.

Results

Sixty-nine TMFs were successfully harvested and used for immediate oncologic palatomaxillary reconstruction in 67 patients (31 males and 36 females, mean age 60.4 years) with diverse primary malignancies. These patients’ co-morbidities included systemic diseases, preoperative chemotherapy/radiotherapy, and elder over 65 years which precluded the ideal utility of free flaps. Fifty-one patients remained alive without disease, while nine had recurrences/metastases and seven died during the follow-up (0.5–10.4 years, mean 3.7 years). All flaps survived with only partial necroses in four cases. Complications and donor-site morbidities were minimal with five transient facial paralysis and four mild diplopia and enophthalmos. Unrestricted diet and mouth opening, intelligible speech, and satisfactory temporal aesthetics were obtained in most patients.

Conclusion

The TMF is a reliable, versatile, and alternative option for oncologic palatomaxillary reconstruction with satisfactory functional and aesthetic outcomes and minimal complications, especially when appropriately selected for those medically compromised patients.     

Biomechanical evaluation of maxillary Lefort Ι fracture with bioabsorbable osteosynthesis internal fixation

The aim of this study was to apply biomechanical analysis model to evaluate the effects of bioabsorbable internal fixation devices on maxillary Lefort Ι fracture. CT scan technology and the finite element software (ansys ) were used to establish three‐dimensional finite element models of five resorbable internal fixation devices in maxillary Lefort Ι fractures. We used the model to calculate the stress of the upper jaw and internal fixation. We further analyzed the stability of fixation under four occlusions. The fixation using two bioabsorbable plates was not stable. The zygomaticomaxillary pillars fixation is more stable than other fixations. The stability of fracture fixation was influenced with the molar occlusion. The current study developed a functional three‐dimensional finite element model of bioabsorbable internal fixation and compared the stability of five fixation methods for maxillary Lefort Ι fractures. The results would facilitate the application of bioabsorbable materials in dental clinic.     

孤独症患者口腔诊疗中的行为控制与治疗方式选择

孤独症是在儿童发育过程中社会行为、语言、兴趣等多方面出现的一类神经精神发育障碍性疾病,近年来,各方资料显示其患病率不断增长。由于孤独症患者存在特殊的口腔疾病表现,诊疗中需要特殊的行为控制并选择合适的治疗方式,加之社会、家庭等多方面因素影响了其口腔保健和疾病的诊治,所以了解一定的临床处理原则和方法对口腔医生非常必要。本文主要针对诊疗中的行为控制技术和治疗方式的选择作一综述。     

传动直丝弓技术矫治骨性Ⅲ类错（牙合）畸形的初步研究

目的 探讨传动直丝弓技术治疗骨性Ⅲ类错（牙合）畸形的特点.方法 20例经传动直丝弓技术治疗的骨性Ⅲ类错（牙合）畸形患者,分析其治疗前后的头颅定位侧位片,评价患者矫治前后软硬组织的变化,总结传动矫正技术的特点.结果 与矫治前对比,矫治患者侧貌和咬合关系有明显改观.矫治后的Wits值由（-2.45±1.78） mm改善为（-1.13±0.92）mm,ANB角由（-1.25±1.63）°增大为（0.78±2.79）°,矫治前后的差异有统计学意义（P＜0.05）.矫治后患者上、下唇突点到SnPg’平面的距离之差由（-3.38±1.48）mm变为（2.09±1.55） mm,面型角由（2.75±1.47）°变为（7.51±1.87）°,矫治前后的差异有统计学意义（P＜0.05）.结论 传动直丝弓技术是治疗骨性Ⅲ类错（牙合）畸形的有效手段.     

个性化护理措施对固定正畸矫治的青少年患者托槽脱落率的影响研究

目的 探讨个体化护理措施对接受固定正畸矫治的青少年患者托槽脱落率的影响.方法 将正畸门诊接受固定矫治的120例青少年患者按性别随机均分为四组,A组女患者30例,B组男患者30例,以上两组患者采用个体化护理措施(由专职护士运用语言、示范、文字等教育相结合的方式,从认知、心理、行为、家庭四个方面进行护理),C组女患者30例,D组男患者30例,采用常规正畸护理健康宣教.分别记录四组患者佩戴固定矫治器1个月时托槽脱落的情况,计算托槽脱落率.将A组与C组、B组与D组、A组与B组、C组与D组,分别进行统计分析.结果 佩戴固定矫治器1个月时,四组患者托槽脱落率分别为o.20％、0.40％、1.57％、1.76％,A组与C组比较、B组与D组比较均存在明显统计学差异(P＜0.05);A组与B组比较、C组与D组比较均没有明显统计学差异(P＞0.05).结论 在青少年固定正畸矫治过程中,性别差异不是影响托槽脱落率的主要因素,护士运用个体化的护理措施,提高了患者的主动配合能力,从而降低了患者托槽的脱落率.     

下颌骨升支骨结核一例

颌骨结核作为肺外结核的少见病近年呈增多趋势,其发病形式、临床表现也有了较大的变化,容易被误诊为炎症或良恶性肿瘤。本文就近期收治的1例发生于下颌升支骨结核的临床表征、病理表现及相关实验室特点作一阐述,并通过文献复习,分析颌骨结核的临床特征,以期引起重视,提高对疾病的认识。     

不同连接方式种植体对周围组织影响的临床比较

目的比较平台转换种植体和传统基台连接种植体对上颌美学区单牙种植周围组织的影响。方法随机选择95例（110枚）上颌美学区单牙种植修复患者,其中Ankylos系统（平台转换）47例（54枚种植体）,Nobel Replace系统（传统基台连接）48例（56枚种植体）。在患者最终修复后36～62个月进行随访,拍摄X线片及临床检查来记录种植体周围骨组织和牙龈组织的状况,比较两组种植体边缘骨吸收量和周围软组织红色美学指数。利用统计学方法分析所得数据。结果不同连接方式种植修复后种植体周围边缘骨吸收量与红色美学指数具有显著差异,平台转换种植体的骨吸收量明显少于传统基台连接组,红色美学指数也高于传统基台连接。结论平台转换种植体在上颌美学区单牙种植修复相较于传统基台连接种植体能更有效的保留周围骨组织且美学效果较佳。