Analysis of 356 pterygomaxillary implants in edentulous arches for fixed prosthesis anchorage.

One thousand eight hundred seventeen implants were placed in the completely edentulous maxillae of 189 patients (122 female; 67 male). The patients' mean age was 60 years (range 28 to 91 years). Three hundred fifty-six of the 1,817 implants were placed in the pterygomaxillary area, and all patients were restored with complete-arch fixed detachable prostheses. The mean number of implants per maxillary prosthesis was 9.0 (range 6 to 15). During stage II surgery and before loading, 41 pterygomaxillary implants (11.5%) were not osseointegrated and were removed. After a mean loading period of 4.68 years (range 0.06 to 9.20 years), 1 additional pterygomaxillary implant was lost. Altogether, 42 of 356 pterygomaxillary implants (11.8%) were removed. Survival rates according to implant size, bone quality, and tooth position were also recorded. This study illustrates a cumulative survival rate of 88.2% for pterygomaxillary site implant placement in edentulous maxillary arches.     

Immediate loading of implants used for orthodontic anchorage

The healing around an immediately loaded screw was described and related to the bone type, manner of loading and observation time. In four adult macaca fasicularis monkeys, 16 titanium vanadium screws were inserted into the infrazygomatic crest and two in the symphysis region. Immediately after insertion, screws were loaded with 25- and 50-g Sentalloy springs extending to the canines. Following an observation period of 1, 2, 4 and 6 months, the screws and the surrounding bone were removed. Undecalcified serial sections perpendicular to the long axis were made and the degree of osseointegration studied. Two of the screws were lost immediately after insertion. Of the remaining screws, osseointegration was present around all, but two. The integration was independent of bone type, trabecular or cortical, but increased with time. Based on the results of this study, the use of screws described in the report can be recommended as anchorage units in cases where conventional anchorage is not possible.     

Analysis of 164 titanium oxide-surface implants in completely edentulous arches for fixed prosthesis anchorage using the pterygomaxillary region

PURPOSE: The purpose of the article was to evaluate the survival rates of TiUnite implants and then compare them to a previous similar study of machined-surface implants. MATERIALS AND METHODS: This report presents the results of 82 consecutive patients treated since the introduction of Nobel Biocare's TiUnite surface. The patients were treated with complete-arch restorations using bilateral pterygomaxillary implants in edentulous maxillae. A total of 840 implants were placed in immediate extraction or healed sites, with a mean of 10 implants placed per patient. RESULTS: In all, 826 of the 840 implants osseointegrated, for a cumulative survival rate (CSR) of 98.3%. One hundred fifty-eight of 164 pterygomaxillary implants successfully osseointegrated, yielding a 96.3% survival rate. DISCUSSION AND CONCLUSION: The results of this complete-arch maxillary prospective study suggest that Br?nemark System TiUnite implants are more predicable than implants with a machined surface. Compared to a similar 1999 study in which the survival rate for machined-surface implants was 92.1%, the present study had a significantly higher survival rate of 98.6% with the TiUnite surface (P < .001). In the pterygomaxillary region, there was an increase of 8% with the TiUnite surface as opposed to the machined surface (P < .001). In addition, 62% of the implants in the present study were immediately loaded, compared to 0% in the machined-surface implant study. The titanium oxide surface appears to assist the healing response of the bone-implant interface.     

Influence of cortical bone anchorage on the primary stability of dental implants

Purpose

This retrospective chart review study assessed patient records to determine implant insertion torque (IT) and implant stability quotient (ISQ) values during implant placement to evaluate the correlation with cortical bone anchorage (mono- or bicortical).

Methods

Primary stability data (IT during implant placement surgery and ISQ values immediately after implant placement) and cone beam computed tomography of 33 patients (165 implants) were assessed. Patients were divided into the following groups: G1, implants with apical cortical bone contact; G2, implants with bicortical bone contact (apical and cervical regions); and G3, implants with cervical cortical bone contact.

Results

Sixty-eight implants were excluded due to cortical bone contact on regions other than implant apical or cervical. Ninety-seven implants were therefore assessed for this study. No implant failure was found after a mean 70.42-month follow-up time. Implants with bicortical anchorage (G2) showed higher IT (64.1 Ncm) during implant placement and higher ISQ values (76) (p?<?0.05). Monocortical implants (G1, apical, and G3, cervical) showed similar IT (G1 52.3 and G3 54.3) and ISQ values (G1 71.9 and G3 73) (p?>?0.05). No correlation (Pearson correlation coefficient) was found between the two stability measurement devices for the different cortical bone anchorages that were analyzed (G1 0.190, G2 0.039, and G3 ??0.027) (p?>?0.05).

Conclusions

Insertion torque values and implant stability quotients were influenced by cortical bone contact. No significant correlation was found between IT and ISQ values—higher insertion torque values do not necessarily lead to higher implant stability quotients.

     

正畸支抗种植体骨整合与稳定性的实验研究

目的　考察正畸支抗种植体的骨整合与稳定性以及二者之间的关系。方法　将HA涂层钛种植体、钛浆喷涂钛种植体、未涂层钛种植体植入狗股骨 ,愈合期后施加 1 96N正畸力 2个月。测量施力后种植体的位置变化和种植体—骨界面的剪切结合强度 ,用扫描电镜观察界面。结果　 3种种植体位移分别为 (- 0 5 0± 1 78)mm、(- 0 0 5± 1 76 )mm、(0 2 9± 1 77)mm ,统计学分析结果显示 ,还不能认为 3种种植体出现移动。 3种种植体—骨界面的剪切结合强度分别是 (2 88± 0 5 5 )MPa、(1 89± 0 81)MPa和 (2 14± 0 49)MPa。HA涂层种植体与骨紧密结合 ,其界面结合强度最高 ;另外 2种种植体与骨的结合强度差异无显著性。结论　虽然HA涂层种植体与骨结合最牢固 ,但 3种种植体—骨界面均可形成骨整合 ,在常规正畸力作用下不会发生明显移动。本项研究结果表明 ,种植体可用作短期的正畸支抗。     

自攻型微螺钉种植体支抗的临床应用研究

目的 研究自攻型微螺钉种植体作为磨牙强支抗的临床应用效果.方法 在30例采用自攻型微螺钉种植体作为磨牙支抗的临床病例中,选择6例已经结束治疗的患者进行分析.6例患者均为骨性Ⅱ类上颌前突患者,拔除上颌双侧第一前磨牙后采用上颌强支抗进行矫治.选择自攻型微螺钉种植体作为上颌支抗,以内收上颌前牙、关闭拔牙间隙.种植体植入部位为上颌第二前磨牙与第一磨牙牙根间的颊侧牙槽间隔,加力值为每侧1.47～1.96 N.对患者拔牙间隙关闭前后的头颅定位侧位片进行分析,测量前牙内收情况和磨牙支抗的变化.结果 6例患者共植入12枚微螺钉种植体,矫治后其上颌前突症状均得到明显改善,上颌切牙切缘平均内收6.06 mm,支抗磨牙平均前移0.44 mm,均获得了磨牙强支抗效果.治疗中,种植体保持稳定,种植体周围的软组织健康.结论 自攻型微螺钉种植体支抗是一种简便、有效的支抗形式,可以满足正畸临床治疗的需要.     

羟基磷灰石涂层钛种植支抗的稳定性

将羟基磷灰石涂层钛种植体处期植入狗颌骨，施以１５０ｇ的正畸力，通过口内及Ｘ线归咎测量，动态研究种植支抗在３个月内的稳定性。结果显示：判断种植支抗的移动应综合采用口内及通过Ｘ线归咎测量两种方法：ＨＡ涂层钛种植支抗的骨内段无移位，而基桩在受力后第２和第３个月倾斜移动。     

微钛板辅助上颌前方牵引支抗稳定性的三维有限元分析

目的　为临床不同方向下进行前方牵引时,不同形态微钛板的选用提供参考。方法　构建6种改良型微钛板及上颌骨的三维有限元模型。对该模型牵引位点施加大小为4.9N/侧,方向为与上颌平面夹角为0°-50°向前下的力,分析各工况下微钛板所受应力及其固位螺钉所受拉力和应力。结果 1.不同微钛板均可固定于上颌骨颧牙槽嵴处且无受力过大或应力中断现象。2.固位螺钉受力具有差异性。角度为0°时,Y3型微钛板固位螺钉受力离散程度较小为3.899,10°-40°时,L3型微钛板固位螺钉受力离散程度较小为4.544、4.170、3.820、3.547,50°时,L2型微钛板固位螺钉受力离散程度较小为2.687。结论　微钛板辅助上颌骨发育不足患者在不同方向下进行前方牵引时,应考虑选用不同形态：牵引方向与平面夹角为0°时,选用Y3型微钛板;夹角为10°-40°时,选用L3型微钛板;夹角为50°时,选用L2型微钛板。     

Retention force of magnets in endosteal implants used for facial prosthesis

This study reports on forces generated by magnets to retain facial prostheses. The retention force was measured in cylindrical magnetic inserts and in telescope magnetic inserts. The forces between insert and secondary magnets were measured at different angles. The mean force in the axial direction was 1.8 N. The force decreased as the angle between force direction and insert-axis increased. The results will help clinicians to insert implants in an optimal position when using them to retain facial prostheses.     

微型种植钉增强正畸支抗的临床稳定性研究及相关危险因素分析

目的：探讨将微型种植钉作为增强支抗措施的临床稳定性,分析影响微型种植钉成功率的危险因素。方法：选择错骀患者48例（男性18例,女性30例,平均年龄23．2±6．5岁）,植入微型种植钉的总数量为152枚,微型种植钉的负载期为10个月,评价11个临床变量与微型种植钉成功率的关系。结果：微型种植钉的总成功率为90．1％,口腔卫生状况、微型种植钉植入部位的牙周组织肿胀、牙周炎史、下颌平面角的高低等与微型种植钉的稳定性密切相关;而宿主因素（年龄、性别）、微型种植钉因素（长度）、微型种植钉植入的设计因素（上下颌骨植入部位、植入微型种植钉的角度、是否即刻负载、微型种植钉的加力方式）等对微型种植钉成功率的影响无显著性差异。结论：针对使用微型种植钉的患者,维持好的口腔卫生、对下颌平面角较高的患者采取谨慎设计、防止微型种植钉周围组织肿胀,对于提高微型种植钉植入的成功率是非常重要的。     

Cantilever fixed prostheses utilizing dental implants: a 10-year retrospective analysis.

OBJECTIVE: The dental literature has been unclear about long-term success of fixed cantilever prostheses supported by dental implants. The disappointing results reported when cantilever fixed partial dentures (FPDs) are supported with natural teeth are not directly applicable to implant cantilever FPDs. This article reports on 10 years of implant-retained fixed prostheses primarily in the maxillary arch using the ITI dental implant system. METHOD AND MATERIALS: Sixty cantilever prostheses using 115 ITI dental implants on 36 patients were placed and monitored over a 10-year period. RESULTS: No implant fractures, abutment fractures, porcelain fractures, prosthesis fractures, soft tissue recession, or radiographic bone loss were recorded. All 60 cantilevered prostheses remain in satisfactory function. CONCLUSION: Positive, long-term results, using implant-retained cantilever FPDs can be achieved by: (1) using a rough surface implant of 4.1 mm or greater; (2) using an implant/abutment design that reduces stacked moving parts and reduces the implant-to-crowns ratio; and (3) using a cementable prosthesis design that eliminates the need for occlusal screw retention.     

影响微螺钉支抗种植体稳定性的相关因素

目的：探讨影响微螺钉种植体作为支抗植入后的稳定性相关因素。方法：回顾性分析在44名患者中植入的100枚微螺钉种植体,临床因素包括患者的性别、年龄,负载的时间,微螺钉的大小,种植的部位。结果：种植成功率为83.0%。即刻负载种植成功率为94.4%明显高于延期负载种植成功率的76.6%,有统计学差异（P＜0.05）。直径1.6mm螺钉种植成功率为93.0%,直径2.0mm螺钉种植成功率为75.4%,两者比较P＜0.05。上颌种植成功率为91.7%,下颌种植成功率为75.0%,两者比较P＜0.05。结论：微螺钉支抗种植体稳定性跟种植部位、种植螺钉的大小以及种植后负载的时间有关,而跟性别、年龄以及牙弓内左右侧、前部后部无关。     

Mini dental implants for long-term fixed and removable prosthetics: a retrospective analysis of 2514 implants placed over a five-year period

Over the past decade, endosseous implants of increasingly smaller diameters have been introduced into the field of dentistry. Small diameter implants (SDIs) are generally 2.75 mm to 3.3 mm in diameter. They are frequently used in cases of limited alveolar anatomy Mini dental implants (MDIs) are smaller than their SDI counterparts, with diameters ranging from 1.8 mm to 2.4 mm. They are suitable for long-term use-a task for which the device was approved by the Food and Drug Administration. The following study describes the authors' experience with MDIs under this indication. Over a 5-year period, 2514 MDIs were placed in 531 patients. The mean duration of follow-up was 2.9 years. The implants supported fixed (1278) and removable prostheses (1236), with nearly equal placement in the mandible and maxilla (1256 and 1258, respectively). The overall implant survival was 94.2%. Based on a Cox proportional hazards model, statistically significant predictors of failure include use in removable prostheses (hazard ratio = 4.28), the posterior maxilla (3.37), atrophic bone (3.32), and cigarette smokers (2.28). Implant failures (145) were attributed to mobility with or without suppuration (19% vs 81%, respectively). The mean failure time for these implants was approximately 6.4 months (193+/-42 days). This temporally correlates with the osseointegration period. A learning curve was established for this procedure, and implant survival improved with placement experience. Based on these results, the authors have devised treatment guidelines for the use of MDIs in long-term fixed and removable prostheses. MDIs are not a panacea; however, proper training enables the general dentist to successfully implement MDIs into clinical practice.     

Clinical follow-up of unilateral, fixed dental prosthesis on maxillary implants

Aims/Background: The aims of the present study were to evaluate (1) the success rate of unilateral maxillary fixed dental prosthesis (FDPs) on implants in patients at a periodontal clinic referred for periodontal treatment, (2) the prevalence of varying mechanical and biological complications and (3) effects of potential risk factors on the success rate. Material and methods: Fifty consecutive patients were invited to participate in a follow‐up. The patients had received FDPs on implants between November 2000 and December 2003 after treatment to achieve optimal peridontal health, and the FDPs had been in function for at least 3 years. A questionnaire was sent to the patients before the follow‐up examination. Forty‐six patients with 116 implants were examined. The follow‐up comprised clinical and radiographic examinations and evaluations of treatment outcome. Results: Before implant treatment, 13% of the teeth were extracted; of these, 80% were extracted due to periodontal disease. No implants had been lost before implant loading. One implant in one patient fractured after 3 years of functional loading and three implants in another patient after 6.5 years. The most frequent mechanical complications were veneer fractures and loose bridge screws. Patients with peri‐implant mucositis had significantly more bleeding on probing around teeth and implants. Patients with peri‐implantitis at the follow‐up had more deep periodontal pockets around their remaining teeth compared with individuals without peri‐implantitis, but these differences were not significant. Smokers had significantly fewer teeth, more periodontal pockets ≥4 mm and a tendency towards greater marginal bone loss at the follow‐up, compared with non‐smokers. Conclusion: In the short term, overloading and bruxism seem more hazardous for implant treatment, compared with a history of periodontitis. To cite this article:
Wahlström M, Sagulin G‐B, Jansson LE. Clinical follow‐up of unilateral, fixed dental prosthesis on maxillary implants
Clin. Oral Impl. Res. 21 , 2010; 1294–1300.
doi: 10.1111/j.1600‐0501.2010.01948.x