The influence of thread geometry on implant osseointegration under immediate loading: a literature review

Implant success is achieved by the synergistic combination of numerous biomechanical factors. This report examines the mechanical aspect of implants. In particular, it is focused on macrodesign such as thread shape, pitch, width and depth, and crestal module of implants. This study reviews the literature regarding the effect of implant thread geometry on primary stability and osseointegration under immediate loading. The search strategy included both in vitro and in vivo studies published in the MEDLINE database from January 2000 to June 2014. Various geometrical parameters are analyzed to evaluate their significance for optimal stress distribution, implant surface area, and bone remodeling responses during the process of osseointegration.     

Impact of different placement depths on the crestal bone level of immediate versus delayed placed platform-switched implants

Purpose

The preservation of peri-implant bone is one requirement for long-term success of dental implants. The purpose of this study was to evaluate the impact of subcrestal placement on the crestal bone level of immediate versus delayed placed implants after loading.

微创拔牙即刻种植的牙龈美学效果观察

目的探讨微创拔牙即刻种植技术的临床特点及修复后的牙龈美学效果。方法21例上前牙单个缺失病例，行不翻瓣微创拔牙同期23颗种植体即刻植入，并且同期安装愈合基台直接暴露于口腔，即非埋入式种植术式，种植体愈合6个月后进行永久修复。种植永久修复后观察时间平均27．6个月（13～51个月）。根据Jemt牙龈乳头指数（papilla index score，PIS）观察种植体永久修复12个月后的近远中牙龈乳头状况，根据Flirhauser的改良红色美学指数观察种植体永久修复1年后与相邻天然牙唇侧龈缘位置的协调性；唇侧软组织与相邻天然牙唇侧牙龈色泽协调性。结果23颗种植体均获得良好的骨结合；种植修复体近远中PIS均为Ⅱ级以上。种植修复体与相邻天然牙唇侧牙龈缘水平位置协调性一致的15颗，8颗不协调；唇侧软组织色泽与相邻天然牙协调一致的18个牙位，5个牙位有轻度差异。结论微创拔牙即刻种植术是一项要求较高的技术，多因素影响软组织美学效果，严格掌控适应证，才能获得理想修复效果。     

单个种植体即刻种植即刻负重骨结合情况的动物实验研究

目的本实验设计了单个种植体即刻种植即刻负重的动物模型,目的在于研究种植体周围硬组织的变化.方法选取8只成年狗,体重10～15 kg.分别拔除每只狗的双侧下颌第二前磨牙;同时,各植入一枚ITI种植体,分别以20Ncm及30Ncm的扭矩旋入.实验侧即刻以树脂冠行上部结构修复,对照侧无负荷.每只狗在植入种植体后和处死后拍X线片,观察其影像学的改变.动物分别于1个月和3个月处死后取标本,观察其组织学的改变.结果16枚种植体中14枚种植体获得良好的骨结合,种植体周围包绕着致密的骨组织,未观察到任何间隙和结缔组织长入.实验侧1枚种植体脱落,对照侧1枚种植体松动.结论单个种植体的即刻种植即刻负重是一个可行的选择.     

Precision surgical template for implant placement: a new systematic approach

The importance of a precise surgical template for implant placement cannot be overstated. The radiographic template carries both clinical and radiographic information for the planning of fixture angulation and location. This article describes a systematic approach to the fabrication of a dual-purpose radiographic surgical template. The simple steps result in the accurate transfer of radiographic information to the surgical template with no need for complex equipment or maneuvers. key words: dental implants, implant placement, radiographic template, surgical template     

即刻负重种植修复的临床观察

目的:观察即刻负重种植修复的临床效果,并对其临床应用问题进行探讨。方法:24例患者共计105个种植体,即刻负重修复缺牙,观察时间12-24个月。结果:1例患者2个种植体修复1个月时脱落;1例患者1个种植体在3个月时脱落;1例患者1个种植体在3个月时因松动而拔出,其余101个种植修复体临床效果良好,成功率达96.19%。结论:选择适当的病例,即刻负重种植修复可应用于临床,近期效果满意。     

前牙区即刻种植的美学效果观察

目的：探讨前牙区即刻种植永久修复后的牙龈美学效果。方法：22例前牙缺失病例,行不翻瓣拔牙同期植入28颗种植体,上前牙24颗采用非埋入式种植术式,下前牙4颗采用埋入式种植术式,种植体愈合3-4个月进行永久修复。随访时间为12-30个月（平均18个月）。根据Miller牙龈边缘组织退缩分类及Jemt牙龈乳头指数,分别观察种植体永久修复12个月后的牙龈边缘退缩及牙龈乳头状况;根据Albrektsson种植体成功标准,观察所植入的种植体状况。结果：28颗种植体留存率100%。Miller分类,18颗种植体牙龈边缘无退缩;8颗种植体牙龈边缘Ⅰ类退缩;2颗种植体牙龈边缘Ⅱ类退缩。种植修复体近远中Jemt牙龈乳头指数均为Ⅱ级以上。结论：前牙区即刻种植,延期修复是一项较成熟的手术方法,但须严格掌握适应症,才能获得良好的修复效果。     

牙周炎患者即刻种植修复的临床观察

目的 评价重度牙周炎患者拔牙后种植治疗并行即刻修复的临床效果.方法 选择在中山大学光华口腔医学院·附属口腔医院种植科就诊的需行义齿修复的重度牙周炎患者12例.术前行完善的牙周治疗,术中拔除余留牙,彻底清创,植入种植体并于手术当日完成树脂临时修复,6个月后行永久修复.术后l、6、12、24个月复诊,评价种植体和修复体存留率及软硬组织状态.结果 植入种植体84枚,上颌50枚、下颌34枚,其中32枚为即刻植入新鲜拔牙窝.3例(4枚)种植体失败,种植体两年存留率为95％,其中上颌92％( 46/50),下颌为100％ (34/34);修复成功率为100％.所有的种植失败均发生在手术后6个月内.即刻种植体植入拔牙窝和种植体植入正常牙槽骨两组在植入扭矩及牙槽骨吸收水平方面差异无统计学意义.结论 本组牙周炎患者行完善牙周治疗后全口种植即刻修复取得满意的修复效果.     

Clinical evaluation of implant survival based on size and site of placement: A retrospective study of immediate implants at single rooted teeth sites

Objectives

This retrospective clinical study sought to evaluate the survival of immediate implants placed at maxillary and mandibular single-rooted tooth extraction sites and to determine the relationship among implant size, placement site, and implant survival.

Methods

Between January 2010 and June 2011, 85 patients (33 males, 52 females; mean age: 45 years) underwent immediate implant placement after extraction of single-rooted teeth. All implants were restored between 12 and 14 weeks after implant placement. The implant survival and its relationship with implant size and implantation site were evaluated by odds ratios (ORs).

Results

Implants were placed at the following sites: upper central incisor (UCI, n = 35), upper lateral incisor (ULI, n = 27), upper second premolar (U2ndP, n = 36), lower incisor (LI, n = 53), and lower premolar (LP, n = 22). Implants of the following sizes were used: 5 × 10 mm (n = 24), 5 × 8 mm (n = 21), 4.3 × 10 mm (n = 77), 4.3 × 8 mm (n = 36), 3.5 × 10 mm (n = 12), and 3.5 × 8 mm (n = 3). After a mean follow-up time of 47 months, the overall implant survival rate was 96%. Survival rate was highest at the LI site (98.1%) and lowest at the ULI site (92.6%). All of the 5-mm implants survived (100%), as did most of the 4.3 × 10 mm implants (96.1%). Implants of 4.3 × 8 mm and 3.5 × 10 mm were the least successful (91.7%). Mandibular implants had a better survival rate (97.3%) than maxillary implants (94.9%). There was no significant OR of increased survival for any particular implant size or site.

Conclusions

Immediate implant placement in fresh extraction sockets can give predictable clinical outcomes, regardless of the implant size and site of placement.     

In-vitro development of a temporal abutment screw to protect osseointegration in immediate loaded implants

PURPOSE

In this study, a temporal abutment fixation screw, designed to fracture in a controlled way upon application of an occlusal force sufficient to produce critical micromotion was developed. The purpose of the screw was to protect the osseointegration of immediate loaded single implants.

MATERIALS AND METHODS

Seven different screw prototypes were examined by fixing titanium abutments to 112 Mozo-Grau external hexagon implants (MG Osseous®; Mozo-Grau, S.A., Valladolid, Spain). Fracture strength was tested at 30° in two subgroups per screw: one under dynamic loading and the other without prior dynamic loading. Dynamic loading was performed in a single-axis chewing simulator using 150,000 load cycles at 50 N. After normal distribution of obtained data was verified by Kolmogorov-Smirnov test, fracture resistance between samples submitted and not submitted to dynamic loading was compared by the use of Student''s t-test. Comparison of fracture resistance among different screw designs was performed by the use of one-way analysis of variance. Confidence interval was set at 95%.

RESULTS

Fractures occurred in all screws, allowing easy retrieval. Screw Prototypes 2, 5 and 6 failed during dynamic loading and exhibited statistically significant differences from the other prototypes.

CONCLUSION

Prototypes 2, 5 and 6 may offer a useful protective mechanism during occlusal overload in immediate loaded implants.     

即刻全负重种植总义齿的临床评价

目的:观察总义齿即刻负重种植修复的临床效果,以及应用中的关键问题.方法:3例患者共计30个种植体,即刻负重总义齿修复,观察时间2年.结果:3例患者的种植总义齿修复体临床效果良好,3个病例全部取得成功.结论:选择适当的病例,即刻负重总义齿种植修复可成功应用于临床,近期效果满意.     

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前牙承担着维持面部美观和语音的重要功能,前牙缺失后采取即刻牙种植历来受到学者的关注.由于前牙位置、功能和局部解剖、组织结构的特殊性,如何兼顾或取舍相关功能,正确选择不同的牙种植体,修复缺失前牙,修复重建并维持骨和牙龈组织,提高即刻种植远期成功率,是前牙即刻种植治疗实施前必须认真思考的.本文在回顾近年相关文献报道的基础上,总结、分析了影响前牙即刻种植的主要因素,探讨了治疗中应该注意的主要问题.     

不翻瓣即刻牙种植临床研究

目的：介绍一种微创的即刻牙种植方法,并对其临床效果尤其是美学效果进行评价。方法：对19例颊侧上端边缘骨板完整、无明显急性根尖或牙周炎症的前牙或前磨牙进行微创拔牙术,清创拔牙窝后不翻瓣即刻植入种植体,接上适当高度和直径的愈合基台,制作塑料过度义齿固定于邻牙。3-6个月后制作永久上部结构。病例随访3-18个月,对种植体周围的软硬组织进行评价。结果：19例患者19颗种植体均获得良好骨结合,随访期内无一种植体松动脱落。种植修复成功率100%。种植体周软硬组织保存良好,种植美学效果令人满意。结论：只要选择好适应症,不翻瓣即刻种植短期可获得有保障性的临床效果,方法确实可行。     

Risk assessment of inferior alveolar nerve injury for immediate implant placement in the posterior mandible: A virtual implant placement study

Objectives

To investigate the prevalence and morphological parameters of lingual concavity, and whether these factors are related to a higher risk of inferior alveolar nerve (IAN) injury when performing an immediate implant surgery in posterior mandible region.

Methods

The CBCT images from 237 subjects (1008 teeth) were analysed the shape of the mandibles (C, P, U type), dimensional parameters of lingual concavity (angle, height, depth), and its relation to inferior alveolar canal (IAC) (A, B, C zone), RAC (distance from root apex to IAC) and probability of IAN injury. Multiple logistic regression modelling to determine the odds ratio of variables that made an important contribution to the probability of IAN injury and to adjust for confounding variables.

Results

The U type ridge (46.7%) and the most concave point located at C zone (48.8%) are most prevalent in this region. The mandibular second molar presents highest risk for IAN injury than other tooth type (p < 0.001), which were 3.82 times to occur IAN injury than the mandibular second premolar. The concave point located at A zone and B zone were 7.82 and 3.52 times than C zone to have IAN damage, respectively. The probability of IAN injury will reduce 26% for every 1 mm increase in RAC (p < 0.001).

Conclusions

The tooth type, morphological features of lingual concavities, and RAC are associated with risks of IAN injury during immediate implant placement.

Clinical significance

Pre-surgical mapping of the IAC and identification of its proximity relative to the lingual concavity in the posterior mandible regions may avoid unpleasant complications, specifically when performing immediate implant procedures.     

下颌磨牙即刻种植临床探讨

目的：介绍一种简单易行的下颌磨牙即刻种植方法并对其临床效果进行评估。方法：20颗下颌磨牙经微创拔牙后,不翻瓣植入特定形状的种植体和愈合基台,无须植入人工骨或覆盖胶原膜,种植体采用穿龈愈合方式。种植体植入3个月后常规印模,完成上部结构修复。种植体完成修复后随访3-24月。结果：所有的种植体均获得良好的骨结合,种植体周软硬组织保持完好,美学效果令人满意。随访期内所有种植牙正常行使功能。结论：下颌磨牙不翻瓣即刻种植方法简单易行,临床效果可靠,减少了手术次数,缩短了治疗时间,降低了治疗费用,值得临床推广。     

Ridge alterations following immediate implant placement and the treatment of bone defects with Bio-Oss in an animal model

Background: Conflicting data exist on the outcome of placing Bio‐Oss® (Geitslich Pharm AG, Wolhausen, Switzerland) into extraction sockets. It is therefore relevant to study whether the incorporation of Bio‐Oss into extraction sockets would influence bone healing outcome at the extraction sites. Purpose: The aim of this study was to assess peri‐implant bone changes when implants were placed in fresh extraction sockets and the remaining defects were filled with Bio‐Oss particles in a canine mandible model. Materials and Methods: Six mongrel dogs were used in the study. In one jaw quadrant of each animal, the fourth mandibular premolars were extracted with an elevation of the mucoperiosteal flap; implants were then placed in the fresh extraction sockets and the remaining defects were filled with Bio‐Oss particles. After 4 months of healing, micro‐computed tomography at the implant sites was performed. Osseointegration was calculated as the percent of implant surface in contact with bone. Additionally, bone height was measured in the peri‐implant bone. Results: Average osseointegration was 28.5% (ranged between 14.8 and 34.2%). The mean crestal bone loss was 4.7 ± 2.1 mm on the buccal aspect, 0.4 ± 0.5 mm on the mesial aspect, 0.4 ± 0.3 mm on the distal aspect, and 0.3 ± 0.4 mm on the lingual aspect. Conclusion: The findings from this study demonstrated that the placement of implants and Bio‐Oss® particles into fresh extraction sockets resulted in significant buccal bone loss with low osseointegration.     

Simultaneous Le Fort I osteotomy and zygomatic implant placement

The aim of this retrospective study was to evaluate the outcomes of simultaneous LeFort I osteotomy and zygomatic/dental implant placement for oral rehabilitation of patients with extremely atrophic/dysmorphic edentulous maxilla.Simultaneous LeFort I osteotomy and zygomatic/dental implant placement was performed with patient-specific anatomical models and surgical guides produced through three-dimensional virtual planning methods. All patients received their final prosthesis, with immediate loading, on the day after surgery. The primary outcome variables were the implant survival rate, and the incidence of intra/postoperative complications. In total, 15 zygomatic implants and 33 conventional dental implants were inserted in eight patients. The mean follow-up of the patients was 38.5 months. The implant survival rate was 93.3% for zygomatic implants and 100% for dental implants. No intra/postoperative complications were observed.Simultaneous LeFort I osteotomy associated with zygomatic/dental implant surgery can be considered as a valuable treatment option for rehabilitation of patients with extremely atrophic edentulous maxilla and esthetic issues of the face.