Zygomatic bone: anatomic bases for osseointegrated implant anchorage

PURPOSE: The aim of the present study was to evaluate zygomatic bone thickness considering a possible relationship between this parameter and cephalic index (CI) for better use of CI in the implant placement technique. MATERIALS AND METHODS: CI was calculated for 60 dry Brazilian skulls. The zygomatic bones of the skulls were divided into 13 standardized sections for measurement. Bilateral measurements of zygomatic bone thickness were made on dry skulls. RESULTS: Sections 5, 6, 8, and 9 were appropriate for implant anchorage in terms of location. The mean thicknesses of these sections were 6.05 mm for section 5, 3.15 mm for section 6, 6.13 mm for section 8, and 4.75 mm for section 9. In only 1 section, section 8, did mean thickness on 1 side of of the skull differ significantly from mean thickness on the other side (P <.001). DISCUSSION: For the relationship between quadrant thickness and CI, sections 6 and 8 varied independently of CI. Section 5 associated with brachycephaly, and section 9 associated with subbrachycephaly, presented variations in the corresponding thickness. CONCLUSION: Based on the results, implants should be placed in sections 5 and 8, since they presented the greatest thickness, except in brachycephalic subjects, where thickness was greatest in section 5, and in subbrachycephalic subjects, where thickness was greatest in section 9. CI did not prove to be an appropriate parameter for evaluating zygomatic bone thickness for this sampling. (More than 50 references.)     

2种上颌窦提升术在牙种植中的应用

目的：比较2种上颌窦提升术同期植入种植体的临床疗效.方法：采用2种上颌窦提升技术,对31例42颗垂直骨量不足的上颌后牙行上颌窦提升术及同期种植体植入术.术后1、3、6个月检查上颌窦及种植体骨结合情况.结果：无种植体松动、脱落及上颌窦炎发生,X线检查种植体与周围组织均形成良好的骨性结合,术后6个月完成义齿修复.经6～36个月随访观察,临床效果良好.结论：掌握适应证和手术技巧,2种上颌窦提升术同期植入种植体的临床疗效均良好.     

Zygomatic implant placement using a robot-assisted flapless protocol: proof of concept

Robotic assistance can help in physically guiding the drilling trajectory during zygomatic implant positioning. A new robot-assisted strategy for a flapless zygomatic implant placement protocol is reported here. In this protocol, a preoperative computed tomography scan is used to plan the surgical path. After surface registration, the ROSA robot (Zimmer Biomet Robotics) guides several steps, which are performed with shared control. The surgeon performs the drilling and tapping, guided by the robotic arm, which is positioned according to the planned trajectory. Placement of the zygomatic implant is done manually. Immediate intraoperative 3D verification is performed by cone beam computed tomography (flat-panel detector, Medtronic O-arm II). Four zygomatic implants were placed in the case patient according to the flapless protocol, with a mean vector error of 1.78 mm (range 0.52–4.70 mm). A screw-retained temporary prosthesis was placed on the same day. No significant complications were observed. The application of this robot-assisted surgical protocol, which guarantees a very high degree of precision, may reduce inaccuracies in the positioning of zygomatic implants that could deviate from the surgeon’s plan. This appears to be a potentially safe flapless surgery technique. Drill slipping on the crest or on the maxillary wall is the main source of error in this procedure, emphasizing the usefulness of the assisted surgical guidance with haptic feedback.     

经牙槽嵴顶入路液压提升法提升上颌窦底黏膜并植骨同期种植的效果评价

目的 探讨经牙槽嵴顶入路液压提升法提升上颌窦底黏膜并植骨同期种植的临床效果。方法 选取经牙槽嵴顶入路液压提升法提升上颌窦底黏膜并植骨同期进行种植体植入术的患者25例,其中男15例,女10例,年龄40～62岁,均为上颌后牙单颗缺失,缺牙区剩余上颌窦骨高度为（4.25±1.12）mm,进行临床检查和影像学检查,评估其临床效果。结果 25例病例上颌窦底提升高度为（8.50±2.12） mm, 术中未发现上颌窦底黏膜破损,同期植入Bio-Oss骨粉并植入种植体25颗。1例患者因种植体感染于术后3周脱落,后检查发现该患者患有糖尿病,暂时放弃再次种植。其余24例患者术后观察未发现明显并发症和不良反应。随访12～18个月,所有种植体均行使良好功能。结论 液压提升法提升上颌窦底黏膜并植骨同期种植安全、可靠,手术创伤小,较传统冲顶式内提升法更加灵活,并可避免敲击震荡给患者带来的恐惧和不适,临床效果较好。     

Simultaneous placement of implant and bone graft in the anterior maxilla: a case report

This article describes a method for harvesting intramembranous bone from the paranasal bone around the piriform aperture for lateral alveolar ridge augmentation and simultaneous implant placement in the anterior maxilla. In particular, the technique is recommended for situations where a maxillary incisal implant is being placed and ridge augmentation is needed to cover exposed threads. Surgical access is simple and can be accomplished by the same incision, and bone harvesting can be accomplished under local anesthesia. Postoperative morbidity is not yet known.     

Combined bony closure of oroantral fistula and sinus lift with mandibular bone grafts for subsequent dental implant placement

Sinus lifting and reconstruction of localized alveolar defects are often required after closure of a large oroantral fistula (OAF) to allow for subsequent implant installation. This study describes a combined surgical technique that involves sinus lifting, bony closure, and reconstruction of the alveolar defect at the site of an OAF. The sinus membrane was reconstructed as a continuous layer by combining the residual sinus membrane with a rotated part of oral mucosa around the OAF. Autogenous bone from the chin and/or ramus was grafted into the prepared sinus space and alveolar defect, and the graft was covered by a buccal advancement flap. This technique was used to treat 8 patients who had large OAFs in the posterior maxillary region. The treatment was successful in all cases, and the technique appears to be suitable for large OAFs where implants are subsequently desired.     

Cortical bone spreader osteotome and method for dental implant placement

This article describes an osteotome designed for placement of dental implants in narrow sites with less dense bone.     

Platelet-rich plasma for bone graft enhancement in sinus floor augmentation with simultaneous implant placement: patient series study

The use of autologous platelet-rich plasma (PRP) as a source for growth factors in bone grafting is a relatively new and promising technique. Early controlled studies indicate that combining PRP with autologous bone grafts significantly enhances the rate of bone formation and maturation. The study consisted of 105 patients who required sinus augmentation with crestal bone height of less than 5 mm in the posterior maxilla. All patients received a composite bone graft that consisted of 30% to 40% autogenous bone harvested from the lateral wall of the maxilla zygomatic-maxillary buttress and the tuberosity and 60% to 70% xenograft. A total of 50 mL of blood was obtained from each patient before the surgical treatment for preparation of 10 mL of PRP. The graft-PRP mixture was activated by human thrombin. All sinus augmentations were carried out simultaneously with dental implants. At 6 months postoperatively, implants were exposed showing no clinical evidence of crestal bone loss around the implants both clinically and radiographically. All implants were clinically osseointegrated and loaded with fixed porcelain fused to metal prosthesis. The use of PRP in augmenting the severely atrophic posterior maxilla has obvious clinical benefits in terms of reducing the healing period of bone maturation, better graft handling, and accelerated soft tissue healing.     

上颌窦内提升植骨及同期牙种植术中中空钻的应用

目的　介绍和评价在上颌窦内提升、植骨及同期牙种植术中使用中空钻的效果。方法对 2 4例牙槽骨高度不足的上颌后牙 ,用中空钻预备种植床、取骨 ,再行上颌窦底内提升 ,将所取的骨碾碎 ,植入上颌窦底 ,同期植入种植体 2 4例。术后 1周 ,1、3、6个月复查。结果　无种植体松动、脱落及上颌窦炎发生。 6个月后 ,X线片显示所植的骨改建成新骨 ,增加了牙槽骨高度 ,满足了种植要求 ;同时可见种植体与新骨形成紧密的骨性结合。种植体植入 6个月后行二期修复。结论　该法解决了上颌后牙区的牙槽骨高度不足 ,避免另处取骨。方法简单 ,值得临床推广。     

Simultaneous sinus membrane elevation and dental implant placement without bone graft: a 6-month follow-up study

Background: Previous studies have shown that simultaneous elevation of the sinus mucosal lining and placement of dental implants without graft materials can be a predictable procedure. Nevertheless, few prospective, controlled, and randomized studies have evaluated this technique. The aim of this prospective, controlled, and randomized clinical study is to evaluate whether sinus membrane elevation and simultaneous placement of dental implants without autogenous bone graft can create sufficient bone support to allow implant success 6 months post‐surgically. Methods: Sinus membrane elevation and simultaneous placement of dental implants were performed bilaterally in 15 patients in a split‐mouth design. The sinuses were assigned to two groups: the test group, with simultaneous sinus mucosal lining elevation and placement of dental implants without graft materials; and the control group, with simultaneous sinus mucosal lining elevation and placement of dental implants with intraoral autogenous bone graft. After 6 months of healing, abutments were connected. For each implant, length of implant protrusion into the sinus, resonance frequency analysis, and bone gain were recorded at baseline and 6 months follow‐up. Results: Clinical complications were not observed, except for two postoperative fistulas and suppuration in both groups. Only one implant of the test group was lost, reaching a success rate of 96.4% and 100% for the test and control groups, respectively. After healing, radiographic new peri‐implant bone was observed in both groups ranging between 8.3 ± 2.6 and 7.9 ± 3.6 mm for the control and test groups, respectively (P >0.05). Resonance frequency analysis values were lower for the control group compared to baseline (P <0.05). However, these values were similar at 6 months (P >0.05). A significant positive correlation was found between the protruded implant length/bone gain and implant survival/sinusitis (P <0.0001). Conclusion: Implants placed simultaneously to sinus membrane elevation without graft material resulted in bone formation over a period of 6 months.     

1例同种异体骨片在唇侧骨板缺损位点即刻种植中的应用

目的 探讨使用同种异体骨片在唇侧骨板缺损位点进行不翻瓣即刻种植的临床效果，以期为该术式的临床应用提供参考。方法 对1例左上前牙残根伴慢性根尖周炎的病例进行不翻瓣即刻种植，应用隧道技术植入同种异体骨片重塑唇侧骨板，联合同期跳跃间隙内植骨和游离结缔组织移植完成软硬组织处理。结果 在种植体植入6个月后完成延期永久修复，CBCT显示植入同种异体骨片在位，间隙内成骨良好，种植体骨结合良好，完成个性化角度螺丝固位全瓷修复体安装。最终牙龈形态协调，PES评分为12分，获得了可接受的临床疗效。结论 同种异体骨片结合不翻瓣种植手术为唇侧骨板缺损位点的即刻种植提供了可预期的临床效果，扩大了即刻种植的临床适应证，减少了手术的创伤，有助于获得理想的临床疗效。     

A model to evaluate bone substitutes for immediate implant placement

A calcified alloplast was evaluated as a gap-filling material around implants placed immediately into fresh extraction sockets. Periodontal measurements and computed tomography scans were obtained to evaluate the clinical effectiveness of the alloplast when compared with demineralized freeze-dried bone. To determine whether this alloplast would be a suitable grafting material, 14 patients were selected to evaluate the extraction socket as a model for routine histologic confirmation of the efficacy and biocompatibility of bone substitutes. The results of this study showed the following: (1) human extraction sockets can be models for the study of bone/implant interaction; (2) the alloplast was well tolerated and demonstrated no inflammation through histologic evaluation of core biopsies; (3) the alloplast was a suitable material when used as a gap-filling graft in sockets around immediately placed implants; and (4) dental computed tomography scans and periodontal measurements around grafted implants 6 months after the procedure provide valuable clinical information about graft healing and osteointegration.     

血浆基质在口腔种植水平骨增量中的应用

牙齿缺失伴随着牙槽骨吸收或缺损,导致骨量和软组织量不足。种植治疗除恢复缺失牙的咀嚼功能外,还需恢复牙弓的轮廓和外形,引导骨再生术是骨增量的常用手段。异种颗粒状骨替代材料因其降解时间长、免疫反应低等优点,在临床水平骨增量领域应用广泛,但存在操作不便、成骨活性低等问题。血浆基质能有效提高口腔组织再生效果、减少术后并发症的出现,在口腔组织再生中的应用逐渐增多。本文首先介绍了血浆基质在水平骨增量中的主要应用形式(固态血浆基质膜、血浆基质骨块),并根据临床常用的骨增量决策方案,即是否能够在理想位置植入种植体以及植入后是否存在骨开裂对水平骨缺损进行重新分类,其中Ⅰ类水平骨缺损为缺牙位点骨量可供植入理想尺寸的种植体,且种植体周围无骨开裂,但牙槽骨轮廓比非缺牙区凹陷的情况;Ⅱ类水平骨缺损为缺牙位点骨量根据未来修复体位置确定的种植位点植入理想尺寸种植体后,种植体三侧均有骨,但颊侧骨壁存在骨开裂(骨开裂长度小于种植体长度的50%)的情况;Ⅲ类水平骨缺损为缺牙位点骨量不足以在理想位置植入理想尺寸的种植体,需要先行植骨恢复骨量以利于种植体植入的情况。本文随后对血浆基质在不同水平骨缺损类型中的应用方法进行阐述:...     

Ramus graft and 1-stage implant placement: a case report

Althougth hard-tissue grafting protocols have typically recommended a 6-month healing period before placement of any dental implants at the graft site, it may be possible to secure an onlay graft to a wide but shallow alveolar ridge using implants that are then submerged and allowed to osseointegrate. This approach has the advantage of expediting treatment and making it less traumatic for the patient. A case is described in which a portion of an edentulous mandible was augmented with ramus bone secured with 2 dental implants.     

Extractions, immediate implant placement and ridge preservation utilizing alloplastic bone graft material. Report of a case

A case report of extractions of periodontally involved teeth with immediate implant placement and ridge preservation using alloplastic material is discussed. The bone graft substitute was for bone maintenance in the extraction sockets and around the dental implants. The case is followed for over one year through the restorative phase.     

Orthodontic space closure versus implant placement in subjects with missing teeth

Summary  The aim was to give a systematic review of alternative orthodontic space closure and implant placement in young adults with missing teeth. A literary search was made in the MEDLINE (Pub Med) database from 1990 to 2007. Totally 146 articles were found. Only studies in the English language or other languages with an English abstract were accepted, which reduced the number to 91 articles. Among them, only one prospective and three retrospective articles, two review papers and five case reports with discussion were found. The others presented one or two cases, or focused on treatment planning of missing teeth in general. Consequently, they were excluded. Moreover, a manual search of bibliographies in relevant journals gave no additional information. Thus, only 11 relevant articles were accepted. This systematic review clearly showed, that both alternatives (space closure or implant placement) present advantages as well as disadvantages. Knowledge about tissue reaction of orthodontic space closure and dento-facial development (including continuous changes of the dentition and its supporting tissues) are significant factors in the choice of treatment. Thus, we need more research on basic level and clinical follow-up studies of large samples.     

Anatomic site evaluation of the zygomatic bone for dental implant placement

Thirty human zygomatic bone specimens (15 females mean age 81.60 +/- 11.38 years, 15 males, mean age 78.47 +/- 6.58 years) were examined by quantitative computed tomography and histomorphometry. The aim of the study was to assess the bone mineral density, the trabecular bone volume and the trabecular bone pattern factor. Moreover, the anterior-posterior and the medio-lateral dimensions and the estimated implant length within the zygomatic bone were determined. For quantitative computed tomography the specimens were scanned together with a bone mimicking anthropomorphic reference phantom. The bone mineral density was calculated for the specimens in the plane of the intended direction of the implant placement. Subsequently, with the sawing and grinding technique, the specimens were prepared in the same plane for histomorphometry. The trabecular bone mineral density was 369.95 +/- 188.80 mg/cm3 for the female and 398.94 +/- 99.11 mg/cm3 for the male specimens (P = 0.23). The male trabecular bone volume showed a value of 27.32 +/- 9.49%, while the female group reached a value of 19.99 +/- 7.60% (P = 0.23). The trabecular bone pattern factor was 1.2 x 10-2 +/- 1.28 mm-1 for the male and 1.02 +/- 0.96 mm-1 for the female specimens (P = 0.045). The study reveals that the zygomatic bone consists of trabecular bone with parameters that are unfavourable for implant placement. However, the success of implants placed in the zygomatic bone is secured by the employment of at least four cortical portions.