Tethering technique using bone screws and wire for chronic mandibular dislocation: a preliminary study of refractory cases

A retrospective study was performed to determine the efficacy of a tethering procedure developed to achieve a more rigid fixation and more reliable outcome in patients with refractory dislocation of the temporomandibular joint. The cases of eight patients with dementia and systemic diseases who underwent this technique were reviewed. In these eight patients, the condyles of 13 joints were ligated using wire between screws placed in the eminence and condylar head. Additional screw–wire ligations were applied to reinforce the restraint of movement in five of the 13 joints with suspected uncontrolled dislocation. The procedure was performed successfully, and the patients were followed-up for an average of 25 months. In one patient, dislocation recurred 1 year postoperatively due to wire breakage. The five joints in which a double set of screw–wire tethering was applied showed no recurrence or wire disturbance. This technique may, therefore, have short-term efficacy in cases that are refractory to standard procedures, although the material used for ligation should be investigated further. This approach can contribute to the quality of life of patients, particularly those with a short life-expectancy.     

关于颌面骨折固定方法研究的回顾

从七十年代末我们开始克氏针内固定治疗髁状突骨折,以后陆续用颌骨螺钉自凝夹板、微型接骨板、动力加压钢板等5种自制器材治疗各种类型的颌面骨折,共计453例,其成功率为94%.本文对器材设计、治愈标准、治疗结果,术后并发症及处理等做了详细论述.     

Correlation between early perforation of cover screws and marginal bone loss: a retrospective study

Aim: This retrospective study aimed to determine the consequence of early cover screw exposure on peri‐implant marginal bone level. Material and Methods: Sixty Astra Tech^® MicroThread implants installed in partially edentulous jaws were compared: 20 implants were placed following a two‐stage procedure and were unintentionally exposed to the oral cavity (two‐stage exposed), 20 implants were placed following a two‐stage procedure and were surgically exposed after a subgingival healing time of 3–6 months (two‐stage submerged), and 20 implants were placed following a one‐stage surgical protocol (one‐stage). Digital radiographs were taken at implant placement for all implants, and after abutment surgery for the two‐stage exposed and two‐stage submerged groups or after 3 months for the one‐stage group. Bone loss mesially and distally was measured with an on‐screen cursor after calibration. Results: Mean bone re‐modelling was 1.96 mm (range: 0.2–3.2 mm) around the two‐stage exposed implants, 0.01 mm (range: 0.0–0.3 mm) around the two‐stage submerged implants and 0.14 mm (range: 0.0–1.2 mm) around the one‐stage implants. Conclusion: The unintentional perforation of two‐stage implants resulted in significant bone destruction, probably because the biological width was not considered.     

下前牙区即刻种植同期引导骨再生结合帐篷式植骨术实施种植修复临床观察（附1例报告）

随着生活水平及治疗技术的提高,种植修复成为越来越多患者的选择。良好的牙槽嵴和牙龈解剖形态的保存或重建是修复体获得满意美学效果和长期稳定性的先决条件。下前牙是牙周炎的好发牙位,下前牙松动脱落伴随下颌骨的吸收势必会造成软硬组织缺陷。文章完整展示了1例罹患重度牙周病变的下前牙即刻种植、同期引导骨再生结合帐篷式植骨术创造良好硬组织三维条件,获得最终较好种植修复效果的具体实施步骤,积累了针对此类问题的临床经验。     

帐篷钉技术在牙槽嵴骨增量中的应用研究

充足的骨量是种植修复成功的关键因素,而临床上种植区骨量不足较为常见,导致难以获得理想的种植体植入方位。因此为确保种植修复的成功和稳定,牙槽嵴的修复与重建具有重要的临床意义。随着骨增量技术的发展,基于引导骨组织再生术基本原理的帐篷钉技术在临床上获得了显著效果,可以在减少甚至不使用自体骨的情况下完成牙槽嵴缺损的修复与重建。本文回顾了帐篷钉技术的发展历史,对其应用原理及条件、临床效果、相关并发症、技术要点以及注意事项等进行综述。     

Fresh‐frozen vs. embalmed bone: is it possible to use formalin‐fixed human bone for biomechanical experiments on implants?

Purpose: As formalin is an extremely reactive electrophilic chemical that reacts with tissues, the purpose of this study was to explore whether formalin fixation could potentially alter the mechanical properties of bone tissue and have an effect on the primary stability measurements of implants.
Material and methods: ∅3.3 × 8 mm, ∅4.1 × 8 mm, and ∅4.8 × 8 mm implants were placed on sockets prepared into the anterior surface of the radius of two fresh-frozen human cadavers. The insertion torque of each implant was quantified using a strain-gauged torque-wrench connected to a data acquisition system at a sample rate of 10 KHz, and resonance frequency analysis measurements were also undertaken for each implant. The cadavers were then subjected to embalment with 10% formalin for 3 months, and the same experiments were undertaken on the contra lateral radius of the cadavers.
Results: The insertion torques before and after chemical fixation were similar for ∅3.3 mm ( P >0.05), and higher values were obtained for ∅4.1 mm and ∅4.8 mm implants after chemical fixation ( P <0.05). The resonance frequency analysis values before and after chemical fixation were similar for all implants ( P >0.05).
Conclusions: Implants have higher insertion torque values in formalin-fixed bone than fresh-frozen human bone, but similar implant stability quotients in both cases. The insertion torque technique can detect the difference between formalin-fixed and fresh-frozen human bone, but resonance frequency analysis cannot.     

帐篷螺丝技术与常规GBR在水平骨增量的临床疗效对比

如今,随着外科技术的创新以及骨替代材料的发展,国内外学者已提出多种水平骨增量技术可以重建牙槽嵴的轮廓,为种植体的初期稳定性提供可靠的保障。然而这些技术的成功也会受到一些因素的影响,本文就水平骨增量的技术要点展开论述,并通过两个病例对帐篷螺丝技术与常规GBR技术用于水平骨增量的临床疗效进行对比、分析,旨在为临床医生对严重牙槽嵴萎缩病例行水平骨增量术的方法选择提供参考。     

A minimally invasive method for titanium mesh fixation with resorbable sutures in guided bone regeneration: A retrospective study

The cover image is based on the Original Article A minimally invasive method for titanium mesh fixation with resorbable sutures in guided bone regeneration: A retrospective study by Songhang Li DDS et al., https://doi.org/10.1111/cid.13147 .

     

牙种植体形态结构设计的研究进展

种植体的初期稳定性和边缘骨水平与周围骨结合密切相关，是临床诊疗中获得较高存活率和成功率的关键因素。牙种植体形态和结构设计包括种植体外部形态、颈部设计、螺纹和凹槽设计、直径和长度、与基台的连接方式等，这些设计会对初期稳定性和边缘骨水平产生不同的影响，从而影响种植体-骨界面的整体稳定性。该文就牙种植体形态结构设计的研究进展进行综述，为临床医生在诊疗过程中选择合适的种植体提供一定帮助。     

Does rotational strain at screw tightening affect the attainment or maintenance of osseointegration?

OBJECTIVES: This study investigated whether rotational strain affects osseointegration. MATERIAL AND METHODS: A total of 135 male rats were divided into five groups: 2-w rotation, 4-w rotation, 8-w rotation, 12-w rotation and control. Two hundred and seventy implants were inserted in rat tibia. The control group received no strain, while the 2-w, 4-w, 8-w and 12-w rotation groups received rotational strain at 2, 4, 8 and 12 weeks after implant placement, respectively. Removal torque (N cm) was measured in vivo. Bone contact rate (%) was calculated histomorphologically. Immunostaining for osteonectin (ON), osteopontin (OPN) and osteocalcin (OCN) was performed. The removal torque and bone contact rate were analyzed using one-way analyses of variance and the Scheffé method. RESULTS: At 4 weeks, the torque was significantly higher in the 2-w rotation group (1.30+/-0.44 N cm) than in the control group (0.79+/-0.67 N cm). From 8 to 16 weeks, the strained groups showed no significant differences from the control group. From the bone contact rates, bone formation was larger in the 4-week rotation group (62.9+/-10.7%) than in the control group (42.1+/-17.9%) at 8 weeks. The 4-week rotation group showed higher bone contact rate (61.1+/-11.3%) compared with the other strained groups and maintained this higher value until 16 weeks, showing no significant difference from the control group (72+/-5.2%). At the implant-bone interface, OPN was widely distributed and OCN was detected at a low level; however, ON could not be observed in any group. CONCLUSIONS: The bone contact rate changed when rotational strain was exerted at different periods after implant placement. However, the removal torque and distribution of extracellular matrix proteins were not adversely affected by the rotational strain.     

Spontaneous early exposure and marginal bone loss around conventionally and early‐placed submerged implants: a double‐blind study

Purpose: The aim of this retrospective study was to compare the frequency of spontaneous early exposure of cover screws and marginal bone resorption in conventionally and early‐placed submerged implants before second‐stage surgery. Materials and methods: A total of 103 Nobel Biocare Branemark implants were conventionally (Group 1), or early‐placed (Group 2) in 46 consecutive patients following the two‐stage surgical protocol. Patients in both groups received oral hygiene training in self‐performed plaque control measures, including exposure of cover screws during healing. Spontaneous cover screw exposure (CSE) of each implant was recorded for both groups and scored from Class 0 (no perforation) to Class 4 (complete exposure). Plaque index scores were recorded and marginal bone‐level (MBL) changes were measured in radiographs before second‐stage surgery in a blind manner. Results: MBL in Group 2 was higher than Group 1 in patients with or without interim prosthesis (P<0.05). The use of interim prosthesis did not increase MBL in Group 1, but led to higher MBL in Group 2. The percentage of non‐exposed implants in Group 1 was higher than Group 2 (P=0.007, odds ratio=7). Group 1 implants had 11.5 times greater plaque index score 0 than those in Group 2 (P=0.031, odds ratio=11.5). The differences between MBL with regard to CSE scores 0 and 1–4 was significant for both sides in Group 2 and the mesial side in Group 1 (P<0.05). The difference between MBL with regard to plaque index scores 1–3 was similar in both groups (P>0.05). Conclusions: There is a direct relation between spontaneous early cover screw perforations with early crestal bone loss. Early‐placed implants experienced more spontaneous perforations and associated bone loss in comparison with conventionally placed submerged implants. The use of interim dentures may lead to more CSE and consequent MBL in the early‐placement protocol. To cite this article:
Çehreli MC, Kökat AM, Uysal S, Akca K. Spontaneous early exposure and marginal bone loss around conventionally and early‐placed submerged implants: a double‐blind study.
Clin. Oral Impl. Res. 21 , 2010; 1327–1333.
doi: 10.1111/j.1600‐0501.2009.01952.x     

Use of self-setting α-tricalcium phosphate for maxillary sinus augmentation in rabbit

Purpose: The purpose of this study was to histologically and immuno‐histochemically evaluate tissue changes in the maxillary sinus after bone screw implantation and maxillary sinus augmentation using self‐setting α‐tricalcium phosphate (α‐TCP; BIOPEX^®‐R) in rabbit. Study design: Adult male Japanese white rabbits (n=15, 12–16 weeks, 2.5–3 kg) were used. The sinus lift was made from the nasal bone of a rabbit. Bone screws (Dual top auto‐screw^®) were implanted into the nasal bone, and after BIOPEX^®‐R was implanted into the left elevated space (operated side) an atelocollagen sponge (ACS: Teruplug^®) was implanted into the right elevated space (control side). The rabbits were sacrificed at 4, 12 and 24 weeks postoperatively, and formalin‐fixed specimens were embedded in acrylic resin. The specimens were stained with hematoxylin and eosin. For immune‐histochemical analysis, the specimens were treated with bone morphogenetic protein‐2 (BMP‐2) antibodies. Finally, these were evaluated microscopically. Results: Tight bonding without fibrous tissue continued between the bone screw and BIOPEX^®‐R, and the rigidity of the bone screw in the nasal bone was retained for 24 weeks in all cases. The area ofnew bone formation increased gradually on both sides; however, there was no significant difference between both sides at 4, 12 and 24 weeks. The number of BMP‐2‐stained cells on the experimental side was significantly larger than that on the control side after 4 weeks (P=0.0361). Conclusion: This study suggested the usefulness of self‐setting α‐TCP (BIOPEX^®‐R) to maintain the rigidity of implanted bone screws from an early period, and the result of BMP‐2 expression suggested that BIOPEX^®‐R could have bone‐conductive activity in the maxillary sinus augmentation. To cite this article:
Marukawa K, Ueki K, Okabe K, Nakagawa K, Yamamoto E. Use of self‐setting α‐tricalcium phosphate for maxillary sinus augmentation in rabbit
Clin. Oral Impl. Res. 22 , 2011; 606–612
doi: 10.1111/j.1600‐0501.2010.02023.x     

Biologic and mechanical stability of single-tooth implants: 4- to 7-year follow-up

Background: Single‐tooth implants have been reported to achieve a high level of surgical and prosthetic success. However, close inspection of the literature reveals a paucity of data on the follow‐up of single‐tooth implants in function for 5 years or more. Since unsplinted implants may be considered to be subject to greater functional stresses, there is a need to report on the long‐term biologic and mechanical integrity of such implant‐supported restorations. Purpose: To report on the long‐term follow‐up of single‐tooth implants, restored and in function for 4 to 7 years. Materials and Methods: Twenty‐seven Astra Tech single‐tooth implants were subject to a clinical audit to evaluate implant and prosthetic success as well as response of both hard and soft tissues over a 1‐ to 4‐year follow‐up. This current report presents data on the biologic and mechanical integrity of 23 of these single‐tooth implants, which have been in function for up to 7 years (mean, 63 mo). Data are provided with respect to implant survival, maintenance of marginal bone levels, soft‐tissue health, and the recording of any adverse events, including prosthetic complications. Results: Only 14 implants in 13 patients were available for review, with no failures for this group of implants. One patient from the original group, who was lost to follow‐up, was known to have suffered an implant failure. Furthermore, in accordance with established criteria, the remaining 13 implants that are not included in this report must at this time also be considered as potential failures. As such, the best‐case scenario would be a 95.6% success rate for the 23 implants included in this review and the worst‐case scenario would be a 60.8% success rate. Mean marginal bone loss measured 0.49 mm mesially and 0.76 mm distally, with a frequency of bone loss of 50%. Soft tissues were clinically healthy. There were few adverse events, with only one case of abutment screw loosening, detected at the 6‐year review. In addition, crown decementation was recorded three times in two patients. Conclusions: It can be concluded that the Astra Tech single‐tooth implant can achieve long‐term biologic and mechanical stability when used to restore single missing teeth, over the long‐term.     

Orthodontic anchorage capacity of short titanium screw implants in the maxilla. An experimental study in the dog.

The aim of this study was to investigate experimentally the effect of long term orthodontic loading on the stability as well as on the peri‐implant bone findings of short titanium screw implants (Bonefit®, submersion depth 6 mm, Ø 4 mm) inserted in regions with reduced vertical bone height. For this purpose, 6 maxillary premolars (₁P₁, ₂P₂, ₃P₃) were extracted from each of 2 foxhounds and reduction of alveolar bone height was performed by osteotomy. After a l6‐week healing period, 8 implants (4 per dog) were inserted in the edentulous areas. Simultaneously, 2 implants (1 per dog) were positioned in the palatal suture (one‐stage surgery). After an 5‐week implant healing period, the fixtures in the Pl/P2 areas ( n = 4) and the palate ( n = 2rpar; were loaded (test implants) by means of transpalatal bars running anteriorly, fixed on the implants in the Pl/P2 areas, and Sentalloy traction springs (‐2 N continuous force) inserted midsagittally between palatal implants and bars (force application period: 26 weeks). The fixtures in the P2/P3 areas served as controls ( n = 4). Clinical measurements and histological evaluation revealed no implant dislocation of the loaded fixtures. These results suggest that short titanium screw implants inserted in the alveolar bone and palatal suture region retain their stability during long‐term orthodontic loading, even following a relatively short unloaded implant healing period. Furthermore, it seems that long‐term orthodontic loading may induce marginal bone apposition adjacent to the implants.     

The Use of a Dental Surgical Microscope to Aid Retrieval of a Fractured Implant Abutment Screw: A Clinical Report

This clinical report outlines a method to retrieve a fractured implant abutment screw through the use of high‐power magnification and ultrasonic instrumentation. Furthermore, the use of manufacturer's specific components is highlighted to minimize occurrences of such clinical complications from arising.