Multidimensional osteodistraction for correction of implant malposition in edentulous segments

This study examined multidimensional osteodistraction as a treatment method for correction of implant malposition and as an alternative to augmentation procedures. The prosthetically unfavourable implant positions were due to growth-related implant malposition (in the context of treatment of young patients with oligodontia) or primary bone-driven implant insertions. The radiographical and clinical findings obtained with this osteodistraction technique are presented and discussed. A tooth-supported osteodistractor for multidimensional distraction with custom-fabricated distraction abutments was used for treatment of 8 patients with a total of 9 maxillary and mandibular edentulous segments including single-tooth gaps. All patients underwent an osteotomy at a minimum distance of 1 mm from the implant surface. Following primary wound healing, distraction was carried out by 1 mm in vertical direction and 0.5 mm in the demanded transverse direction daily until the prosthetically optimized position was achieved. During and after the 12-week retention phase, the patients were evaluated clinically and radiographically. Multidimensional osteodistraction was carried out successfully in all 8 patients. The distraction distances were 3 to 11 mm in vertical direction and a maximum of 5 mm in buccolingual/buccopalatal direction. The malpositioned implants were brought into a prosthetically optimized position in all cases. The results of this study show that this multidimensional osteodistraction technique allows both augmentation of edentulous segments with a clearly compromised implant host site and correction of unfavourable implant positions.     

Distribution of interleukin-2 receptor α-chain and cells expressing major histocompatibility complex class II antigen in chronic human periapical lesions

In situ distribution of CD2⁺ T-lymphocytes, CD4⁺ and CD8⁺ T-cell subsets, CD14⁺ macrophages, interleukin-2 receptor α-chain (IL-2Rα) and class II major histocompatibility complex antigen (major histocompatibility complex class II, HLA-DR) expressing cells were determined in 14 chronic human periapical granulomas by imrnunohistochemical method using monoclonal antibodies. CD2⁺ lymphocytes were rather evenly distributed within the classical granulation tissue and comprised 55% of the mononuclear cells. Macrophages were distributed all over the periapical area, but their proportion was much less than that of T lymphocytes. Both small, lymphocyte-like mononuclear cells and larger mononuclear cells resembling macrophages displayed mild to strong circumferential staining with the anti-HLA-DR antibody. The majority of lymphocytes expressed IL-2Rα indicating the activated state of T cells within the lesion.     

变速牵引成骨对兔下牙槽神经的影响

目的　研究变速牵引兔下颌骨15mm对下牙槽神经的影响。方法　5只新西兰白兔单侧下颌骨截开。延迟5d ,以每天1 5mm ,每天2次牵引9mm ,然后继续以每天1mm ,每天2次牵引6mm ,完成牵引后固定15周,分别行肉眼及组织学观察和电生理学检查。结果　下颌骨延长15mm ,新骨生成良好。下牙槽神经牵长2 1. 99% ,牵引结束时神经变性明显,感觉神经动作电位波幅下降为术前的9. 70 % ,潜伏期较术前有所延长,随后出现恢复趋势,到固定15周时,波幅恢复到术前的33. 85 % ,潜伏期基本恢复正常。结论　下颌骨变速牵引15mm后,下牙槽神经受到明显的影响,到15周时,下牙槽神经的功能有恢复的趋势,但恢复尚不完全。     

颏管的解剖学研究

应用国际上先进的，具有高分辨率的Sens-A-Ray新技术，对24例（48例）游离干下颌骨标本的下颌骨标本的下颌管前部结构进行放射投照及计算机测量分析。结果表明：下颌管的前端确有一骨内前绊（颏管）延伸至颏孔前方，继而向后上外方通向颏孔，而并非如过去一般认为的下颌管自后上内向前下外方向直接开口于颏孔。本研究对颏管与颏孔及下颌管之间的关系，颏管的角度等提供了解剖学数据，为临床上颏孔区手术，特别是牙种植术提供了新的解剖学资料。     

Quality and quantity of bone following alveolar distraction osteogenesis in the human mandible

PURPOSE: The purpose of this prospective study on humans were to evaluate (a) the clinical outcome of alveolar distraction osteogenesis for the correction of vertically deficient edentulous mandibular ridges, (b) the clinical outcome of dental implants placed in the distracted areas, and (c) the quality and quantity of the bone that had formed in the distraction gap. MATERIAL AND METHODS: Seven patients presenting vertically deficient edentulous ridges were treated by means of distraction osteogenesis with an intraoral alveolar distractor. Approximately 3 months after consolidation of the distracted segments, 20 ITI solid screw SLA implants were placed in the distracted areas. Three to 4 months later, abutments were connected and prosthetic loading of the implants started. During implant site preparation, bone biopsies were taken at the implant sites with trephine burrs for histologic and histometric analyses. RESULTS: The mean follow-up after the initial prosthetic loading was 18 months (range 12-24 months). The mean bone gain obtained at the end of distraction was 7 mm (range 5-9 mm). The cumulative success rate of implants 2 years after the onset of prosthetic loading was 95%, whereas the survival rate of implants was 100%. The newly formed bone consisted of woven bone reinforced by parallel-fibered bone with bone marrow spaces between the bone trabeculae. The bone area fraction in the distraction region ranged from 21.6% to 57.8% (38.5+/-11.7%). DISCUSSION AND CONCLUSIONS: Results from this study showed that (a) distraction osteogenesis is a reliable technique for the correction of vertically deficient edentulous ridges, (b) the regenerated bone withstood the functional demands of implant loading, (c) survival and success rates of implants placed in the distracted areas were consistent with those of implants placed in native bone, and (d) there is sufficient bone volume and maturity in the distracted region for primary stability of the implant.     

Comparison of two early loading protocols in full arch reconstructions in the edentulous maxilla using the Cresco prosthetic system: a three-arm parallel group randomized-controlled trial

Objectives: Appraise the feasibility of interchanging conventional components of a fixed dental prosthesis (FDP) with those of Cresco in two different early loading protocols. Material and methods: In five centers patients with an edentulous, fully healed maxilla were recruited to partake in a three‐arm blinded randomized‐controlled trial (RCT). Each patient received 5/6 implants using a single‐stage surgery approach to support a 10/12‐unit FDP. The implants used were SLA solid screw two‐part implants. In test groups 1 and 2 components from Cresco were used and the implants loaded 10 days or 6–8 weeks post‐implant placement. Group 3 received their FDP fabricated with conventional components 6–8 weeks post‐implant placement. Patients were followed up 3 years. Results: Of 36 patients, 30 remained after 3 years. The adjusted means and ranges of changes in crestal bone levels were ?0.65, ?0.5 and ?0.4 mm in groups 1, 2 and 3, respectively. The change from baseline was statistically significant in all treatment groups. Adjusting for the difference in implant depth, there was an expected additional change in bone level of ?0.29 mm by each 1 mm the implant was placed deeper. There was no significant difference between the 6‐8 weeks post‐implant placement loading Cresco group vs. the control group or between the two Cresco groups. Conclusions: The vertical placement has more effect on bone loss than the fabrication technique used for the suprastructure and whether the implants were loaded after 10 days vs. 6–8 weeks. To cite this article :
Jokstad A, Ellner S, Gussgard A. Comparison of two early loading protocols in full arch reconstructions in the edentulous maxilla using the Cresco prosthetic system: a three‐arm parallel group randomized‐controlled trial.
Clin. Oral Impl. Res. 22 , 2011; 455–463.
doi: 10.1111/j.1600‐0501.2010.02156.x     

Alveolar ridge dimensions in maxillary posterior sextants: a retrospective comparative study of dentate and edentulous sites using computerized tomography data

Aim: To compare the alveolar ridge dimensions between edentulous sites and contralateral dentate sites of maxillary posterior sextants in the same individuals. Materials and methods: Computerized tomography scans of 32 patients with one fully edentulous and one fully dentate maxillary posterior sextants were analyzed. Results: When compared with dentate sextants, edentulous sextants showed (i) a lower bone height (BH) at second premolar, first molar and second molar sites, which was associated with a more coronal position of the maxillary sinus floor at second premolar site; (ii) a more apical position of the ridge at second premolar and second molar sites; (iii) a lower bone width (BW)_{1 mm} at first and second premolar sites, and a lower BW_{3 mm} at all sites, (iv) a lower, although not significant, prevalence of premolar and molar sites with BH≥8 mm and BW_{1 mm}≥6 mm. Conclusions: The edentulous sextants in the posterior maxilla showed a reduced height and width of the ridge when compared with contralateral dentate sextants. The reduced vertical dimensions observed in edentulous sextants were variably associated with ridge resorption as well as sinus pneumatization. To cite this article:
Farina R, Pramstraller M, Franceschetti G, Pramstraller C, Trombelli L. Alveolar ridge dimensions in maxillary posterior sextants: a retrospective comparative study of dentate and edentulous sites using computerized tomography data.
Clin. Oral Impl. Res. 22 , 2011; 1138–1144.
doi: 10.1111/j.1600‐0501.2010.02087.x     

The influence of perforating the autogenous block bone and the recipient bed in dogs. Part I: a radiographic analysis

Objectives: This study evaluated radiographically the integration and volume maintenance of grafted autogenous block bone under various cortical bone perforation conditions in dogs. Material and methods: Five mongrel dogs were used. Each dog received four differently prepared onlay block bone grafts: a solid block graft was fixed on either (1) a cortically perforated recipient bed (SGPR) or (2) a nonperforated recipient bed (SGNPR), a perforated block graft was fixed on either (3) a nonperforated recipient bed (PGNPR) or (4) a cortically perforated recipient bed (PGPR). The animals were sacrificed at 1 day, 4 days, 10 days, 4 weeks, and 8 weeks after surgery. Specimens were prepared and radiographic analysis was conducted by using micro‐computed tomography. The residual bone volume (RBV; mm³), cross‐sectional bone area (BA; mm²), and residual height (RH; %) of the grafted block bone were measured radiographically. Results: The interface between the recipient bed and the graft showed no signs of bone integration at 1, 4, and 10 days of healing. However, at 4 weeks of healing, bone integration was observed in all groups. The RBV, BA, and RH of the grafts gradually decreased by 4 weeks of healing. At 8 weeks, the PGPR condition exhibited a higher RBV, BA, and RH than the other conditions, whereas the SGNPR condition exhibited the lowest RBV, BA, and RH. Conclusion: Within the limitations of this study, it can be concluded that intentional cortical perforation on the recipient bed and block bone graft may influence volume maintenance of the graft. To cite this article:
Oh K‐C, Cha J‐K, Kim C‐S, Choi S‐H, Chai J‐K, Jung U‐W. The influence of perforating the autogenous block bone and the recipient bed in dogs. Part I: a radiographic analysis.
Clin. Oral Impl. Res. 22 , 2011; 1298–1302.
doi: 10.1111/j.1600‐0501.2010.02110.x     

Do buffered local anesthetics provide more successful anesthesia than nonbuffered solutions in patients with pulpally involved teeth requiring dental therapy?: A systematic review

Background

The authors conducted a systematic review that addresses the following population, intervention, comparison, outcome question: “In adults requiring dental therapy with pulpally involved teeth, what is the comparative efficacy of buffered local anesthetics (LAs) compared with that of nonbuffered LAs in achieving anesthetic success?”