Maxillary Sinus Augmentation Using Prehydrated Corticocancellous Porcine Bone: Hystomorphometric Evaluation after 6 Months

Background: Insufficient alveolar bone height often prevents the placement of standard dental implants in the posterior part of edentulous maxilla. In order to increase adequately the vertical dimension of the reabsorbed alveolar process, a sinus lift procedure is often necessary. The aim of this study was to evaluate histologic results of a prehydrated corticocancellous porcine bone used in maxillary sinus augmentation. Methods: Patients (age 18–70 years) with a residual bone height requiring a maxillary sinus augmentation procedure to place dental implants were eligible for this study. All patients were treated with the same surgical technique consisting of sinus floor augmentation via a lateral approach. The space obtained by elevation of the mucosa wall was grafted with prehydrated and collagenated corticocancellous porcine bone. Biopsies were harvested 6 months after the augmentation procedures. Results: Twenty‐four patients were enrolled. The mean percentage of new formed bone was 43.9 ± 18.6% (range 7.5–100%), whereas the mean percentage of residual graft material was 14.2 ± 13.6% (range 0–41.9%). The new bone/residual graft material ratio in the maxillary sinuses was 3.1. The mean soft tissues percentage was 41.8 ± 22.7% (range 0–92.5%). Conclusion: The present study suggested that porcine bone showed excellent osteoconductive properties and could be used successfully for sinus augmentation. Moreover, the porcine bone showed a high percentage of reabsorption after 6 months; this might be because of the presence of collagen and the porosity of the graft material.     

Enamel Matrix Derivative in Intrabony Defects: Prognostic Parameters of Clinical and Radiographic Treatment Outcomes

Background: The purpose of this retrospective case series study is to identify possible preoperative parameters that could predict postoperative probing depth (PD), clinical attachment level (CAL) gain, or radiographic defect resolution in intrabony defects treated with enamel matrix derivative (EMD). Methods: Sixty‐one chronic periodontitis patients, each contributing a 2‐ or 3‐wall intrabony defect treated with EMD, were included. Clinical parameters recorded included the following: PD; CAL; gingival margin position; supracrestal soft tissue (SST); surgical distances of cemento‐enamel junction (CEJ) to bone crest (CEJ‐BC), CEJ to base of the defect (CEJ‐BD), and BC to BD (BC‐BD); and depth of 2‐ and 3‐wall components. Radiographic parameters recorded included the following: CEJ‐BC, CEJ‐BD, BC‐BD distances, and radiographic defect angle. Postoperative assessments were performed at 12 months. Results: The probability of postoperative PD >4 mm increased 1.6‐fold (odds ratio [OR] = 1.6; 95% confidence interval [CI] = 1.2 to 2.3) with each 1‐mm baseline PD increase. Baseline PD and surgical CEJ‐BD were statistically significant predictors of CAL gain; the greater the baseline PD (OR = 0.5; 95% CI = 0.3 to 0.8) and bone loss (OR = 0.6; 95% CI = 0.3 to 0.9), the less likely that postoperative CAL gain was ≤3 mm. Smoking and SST were significantly associated with defect resolution; failure to achieve ≥65% defect resolution was six‐fold greater for smokers (OR = 6.5; 95% CI = 1.7 to 24.5) and almost double (OR = 1.7; 95% CI = 1.1 to 2.8) for each millimeter of SST increase. Conclusion: In EMD‐treated intrabony defects, baseline PD predicts both CAL gain and postoperative PD. Smoking and SST are predictors of defect resolution.     

����ͻ��ֲ�ǵ���������

牙槽突裂植骨术已成为唇腭裂序列治疗中必不可少的一个环节,但其术后的评价目前还没有一个统一的标准。自从1986年Bergland提出牙槽突植骨分级标准以来,得到了全世界唇腭裂序列治疗专家们的广泛认可。但随着现代医疗技术的发展,尤其是三维CT技术的发展,为牙槽突植骨分级提供了更好、更新标准的可能。牙槽突植骨的评价不应只在二维X线片的基础上,应该建立在三维CT的基础上。因为牙槽突植骨是在一个有一定立体的空间内进行的。所以,牙槽突植骨的评价应该是三维空间的一个完整的评价。目前中国学者在这一方面已经做了一些良好的尝试。     

骨水平Xive种植体系统用于前牙美学修复的临床研究

目的:美学效果是种植修复追求的目标之一,相比功能方面的修复成功而言,实现美学方面的修复成功要更为困难,通常需要较为复杂的手术处理。本研究采用一种微创手术模式和简化的修复治疗程序,在前牙区植入骨水平种植体,评价其美学效果。方法:16例前牙缺失患者纳入本研究。所有患者经过全面检查,并做美学风险评估。采用不翻瓣加骨膨胀手术方法植入Xi ve骨水平种植体,术后连接基台,制作树脂牙冠即刻完成临时修复。四个月后更换为烤瓷牙冠完成恒久修复。观察种植体周硬软组织的变化,并对最终美学修复效果做临床评价。结果:16例患者所植入的22枚种植体在平均观察期8.3个月(5-24个月)无松动脱落。所有患者对修复结果都高度满意。种植修复的白色美学效果,受制于技工制作水平显得不太理想,而粉红色美学效果与患者组织条件有关,但与术前比较,种植体区硬软组织均有明显改善。结论:种植即刻暂时修复体,既可以满足患者美观需要,又对软组织实施了诱导成形。不翻瓣加骨膨胀手术方法,有利于增加种植体区硬软组织量,减少骨吸收,避免牙龈退缩,并避免牙龈组织的瘢痕形成,有利于获得较好的健康的软组织美学,其远期效果还有待继续观察。     

Marginal bone loss adjacent to conventional and immediate loaded two implants supporting a ball-retained mandibular overdenture: a 3-year randomized clinical trial

Objectives: The aim of this study was to evaluate and compare marginal bone loss and clinical outcomes of conventionally and immediately loaded two implants supporting a ball‐retained mandibular overdenture. Materials and methods: Thirty six completely edentulous patients (22 males and 14 females) were randomly assigned into two groups. Each patient received two implants in the canine area of the mandible after a minimal flap reflection. Implants were loaded by mandibular overdentures either 3 months (conventional loading group) or the same day (immediate loading group) after implant placement. Ball attachments were used to retain all overdentures to the implants. Vertical and horizontal alveolar bone losses were evaluated in both groups 1 and 3 years after implant placement using multislice computed tomography, which allow evaluation of peri‐implant buccal and lingual alveolar bone. Plaque scores, gingival scores, probing depths and periotest values (PTVs) were evaluated at 4 months (baseline), 1 and 3 years after implant placement. Clinical and radiographic evaluations were performed at distal, labial, mesial and lingual peri‐implant sites. Results: After 3 years of follow‐up period, the immediate loading group recorded significant vertical bone loss at distal and labial sites than the conventional loading group and no significant differences in horizontal bone loss between groups were observed. Probing depth at distal and labial sites in the immediate loading group were higher than the conventional loading group, while plaque scores, gingival scores and PTVs showed no significant differences between the two groups. A low level of positive correlation between plaque scores, gingival scores, probing depths and vertical bone loss was noted. Conclusion: Immediately loaded two implants supporting a ball‐retained mandibular overdenture are associated with more marginal bone resorption and increased probing depths when compared with conventionally loaded implants after 3 years. The bone resorption and probing depths at distal and labial sites are significantly higher than those at mesial and lingual sites. Clinical outcomes do not differ significantly between loading protocols. To cite this article :
Elsyad MA, Al‐Mahdy YF, Fouad MM. Marginal bone loss adjacent to conventional and immediate loaded two implants supporting a ball‐retained mandibular overdenture: a 3‐year randomized clinical trial.
Clin. Oral Impl. Res. 23 , 23, 2012 496‐503.
doi: 10.1111/j.1600‐0501.2011.02173.x     

Histological evaluation of healing after transalveolar maxillary sinus augmentation with bioglass and autogenous bone

Objectives: The aim was to evaluate histologically the outcome of a bioglass and autogenous bone (at 1 : 1 ratio) composite implantation for transalveolar sinus augmentation. Methods: In 31 patients, during implant installation ca. 4 months after sinus augmentation, biopsies were harvested through the transalveolar osteotomy by means of a trephine bur and non‐decalcified sections through the long axis of the cylinder were produced. After a strict selection process, taking into account the presurgical residual bone height and biopsy length, 8 and 15 biopsies representing the new tissues formed inside the sinus and the transalveolar osteotomy, respectively, qualified for analysis. The tissue fractions occupied by newly formed bone (mineralized tissue+bone marrow), soft connective tissue, residual biomaterial+empty spaces, and debris inside the sinus cavity or the transalveolar osteotomy were estimated. Results: Bone and connective tissue fraction in the newly formed tissues inside the sinus cavity averaged 23.4 ± 13.2% and 54.1 ± 23.5%, respectively. Residual biomaterial, empty spaces, and debris averaged 1.9 ± 3.5%, 10.5 ± 6.3%, and 8.4 ± 14.5%, respectively. In the transalveolar osteotomy, bone and connective tissue fraction averaged 41.6 ± 14.3% and 46.1 ± 13%, respectively, while the amount of residual biomaterial, empty spaces, and debris was 2.8 ± 5%, 4.7 ± 1.9%, and 3.2 ± 2.6%, respectively. Statistically significant differences between the sinus cavity and the transalveolar osteotomy were found only for bone and empty spaces' values (P=0.02 and 0.04, respectively). Conclusion: Sinus augmentation with a bioglass and autogenous bone composite is compatible with bone formation that, in a short distance from the floor of the sinus, shows similar density as that reported previously for other commonly used bone substitutes. New bone fraction inside the transalveolar osteotomy was almost twice as much as in the sinus cavity, while the amount of residual biomaterial was much less than that inside the sinus. To cite this article :
Stavropoulos A, Sima C, Sima A, Nyengaard J, Karring T, Sculean A. Histological evaluation of healing after transalveolar maxillary sinus augmentation with bioglass and autogenous bone.
Clin. Oral Impl. Res. 23 , 2012; 125–131.
doi: 10.1111/j.1600‐0501.2011.02161.x     

Bone healing pattern in surgically created circumferential defects around submerged implants: an experimental study in dog

Objective: To describe the healing of marginal defects below or above 1 mm of dimension around submerged implants in a dog model. Material and methods: In 12 Labrador dogs, all mandibular premolars and first molars were extracted bilaterally. After 3 months of healing, full‐thickness flaps were elevated in the edentulous region of the right side of the mandible. Two recipient sites were prepared and the marginal 5 mm were widened to such an extent to obtain, after implant installation, a marginal gap of 0.5 mm at the mesial site (small defect) and of 1.25 mm at the distal site (large defect). Titanium healing caps were affixed to the implants and the flaps were sutured allowing a fully submerged healing. The experimental procedures were subsequently performed in the left side of the mandible. The timing of the experiments and sacrifices were planned in such a way to obtain biopsies representing the healing after 5, 10, 20 and 30 days. Ground sections were prepared and histomorphometrically analyzed. Results: The filling of the defect with newly formed bone was incomplete after 1 month of healing in all specimens. Bone formation occurred from the base and the lateral walls of the defects. A larger volume of new bone was formed in the large compared with the small defects. Most of the new bone at the large defect was formed between the 10‐ and the 20‐day period of healing. After 1 month of healing, the outline of the newly formed bone was, however, located at a similar distance from the implant surface (about 0.4 mm) at both defect types. Only minor newly formed bone in contact with the implant, starting from the base of the defects, was seen at the large defects (about 0.8 mm) while a larger amount was detected at the small defects (about 2.2 mm). Conclusion: Marginal defects around titanium implants appeared to regenerate in 20–30 days by means of a distance osteogenesis. The bone fill of the defects was, however, incomplete after 1 month. To cite this article:
Rossi F, Botticelli D, Pantani F, Pereira FP, Salata LA, Lang NP. Bone healing pattern in surgically created circumferential defects around submerged implants: an experimental study in dog.
Clin. Oral Impl. Res 23 , 2012; 41–48.
doi: 10.1111/j.1600‐0501.2011.02170.x     

Enhanced bone regeneration around dental implant with bone morphogenetic protein 2 gene and vascular endothelial growth factor protein delivery

Objective: To evaluate the synergistic effect of bone morphogenetic protein 2 (BMP‐2) and vascular endothelial growth factor (VEGF) on the repair of bone defects around dental implants. Material and methods: Five groups of scaffold were fabricated by a freeze‐drying method, including pure chitosan/collagen scaffold; scaffold loaded with adenoviruses expressing BMP‐2, adenoviruses expressing VEGF, both adenoviruses expressing BMP‐2 and VEGF, VEGF protein and adenovirus expressing BMP‐2. In vitro studies examined whether bone marrow stromal cells were responsive to these scaffolds over time. Bone formation capacity, bone‐to‐implant contact, as well as removal torque values were investigated in vivo. Differences between the various groups were statistically analyzed using the one‐way analysis of variance test. Results: The in vitro study revealed a burst and rapid release of VEGF with a sustained high‐level expression of BMP‐2 in scaffold combined with VEGF protein and adenoviruses expressing BMP‐2. Histomorphometry demonstrated that scaffolds expressing BMP‐2 enhanced more bone formation compared with other groups; VEGF alone is insufficient to promote bone formation. New bone formation in the bone defects around dental implants, bone‐to‐implant contact and mean peak removal torque showed statistically significant difference for the adenoviral vector encoding human bone morphogenetic protein 2 (Ad‐BMP‐2) and VEGF protein and adenovirus expressing BMP‐2 groups. Furthermore, scaffold combined with VEGF protein and Ad‐BMP‐2 represented the best outcomes in this model. Conclusions: A combination of BMP‐2 gene and VEGF protein could have a synergistic effect in promoting bone healing. To cite this article:
Luo T, Zhang W, Shi B, Cheng X, Zhang Y. Enhanced bone regeneration around dental implant with bone morphogenetic protein 2 gene and vascular endothelial growth factor protein delivery.
Clin. Oral Impl. Res. 23 , 2012 467–474.
doi: 10.1111/j.1600‐0501.2011.02164.x     

Osteogenic potential of mesenchymal cells embedded in the provisional matrix after a 6-week healing period in augmented and non-augmented extraction sockets: an immunohistochemical prospective pilot study in humans

Purpose: The aim of the present clinical study was the evaluation of the osteogenic potential of mesenchymal cells embedded in the provisional matrix of non‐augmented and with Bio‐Oss collagen‐augmented human extraction sockets after 6 weeks of healing time. Methods: Twenty‐five patients with 47 extraction sites participated in the present study. After tooth removal, the extraction sockets were augmented with Bio‐Oss collagen or not augmented. At implant placement, bone biopsies of the extraction sockets were obtained. The immunohistochemical analysis of the osteogenic potential of the mesenchymal cells in the provisional matrix was performed using three monoclonal antibodies: core‐binding factor α1 (Cbfa1)/runt‐related protein (Runx)2, osteonectin (OSN/secreted protein acidic and rich in cyst [SPARC]) and osteocalcin (OC). The statistical analysis was performed using two‐factorial analysis for repeated measures, Mann–Whitney U‐test and Spearman's rank‐order correlation coefficient. Results: Of 47 extraction sockets examined, 17 sockets demonstrated an almost complete ossification. Hence, the provisional matrix of the 30 remaining extraction sockets (21 non‐augmented, 9 augmented) was immunohistochemically investigated. No evidence of acute or chronic inflammation was noted in any of the specimens. In the provisional matrix of the non‐grafted socket, the median amount of Cbfa1/Runx2‐positive cells was 72.3%, of OSN (SPARC) 66.9% and of OC 23.4%, whereas in the grafted sockets the median rate of immunopositive cells staining with Cbfa1/Runx2 was 73.3%, of OSN (SPARC) 61.4% and of OC 20.1%. There was no significant difference in the proportion of positive cells expressed by Cbfa1/Runx2, OSN/SPARC and OC between the grafted and non‐grafted socket. Furthermore, the cell density did not correlate to the quantity of stained cells independent of the used proteins. Discussion: After a 6‐week healing period, the provisional matrix was demonstrated to have a high proportion of cells displaying a maturation of mature osteoprogenitor cells to osteoblasts. The grafting procedure did not influence the quantity of osteogenic cells in the extraction socket. To cite this article:
Heberer S, Wustlich A, Lage H, Nelson JJ, Nelson K. Osteogenic potential of mesenchymal cells embedded in the provisional matrix after a 6‐week healing period in augmented and non‐augmented extraction sockets: an immunohistochemical prospective pilot study in humans.
Clin. Oral Impl. Res. 23 , 2012; 19–27.
doi: 10.1111/j.1600‐0501.2010.02148.x     

A Double-Blind Randomized Controlled Trial (RCT) of Titanium-13Zirconium versus Titanium Grade IV Small-Diameter Bone Level Implants in Edentulous Mandibles - Results from a 1-Year Observation Period

Background: The use of endosseous dental implants has become common practice for the rehabilitation of edentulous patients, and a two‐implant overdenture has been recommended as the standard of care. The use of small‐diameter implants may extend treatment options and reduce the necessity for bone augmentation. However, the mechanical strength of titanium is limited, so titanium alloys with greater tensile and fatigue strength may be preferable. Purpose: This randomized, controlled, double‐blind, multicenter study investigated in a split‐mouth model whether small‐diameter implants made from Titanium‐13Zirconium alloy (TiZr, Roxolid?) perform at least as well as Titanium Grade IV implants. Methods and Materials: Patients with an edentulous mandible received one TiZr and one Ti Grade IV small‐diameter bone level implant (3.3 mm, SLActive®) in the interforaminal region. The site distribution was randomized and double‐blinded. Outcome measures included change in radiological peri‐implant bone level from surgery to 12 months post‐insertion (primary), implant survival, success, soft tissue conditions, and safety (secondary). Results: Of 91 treated patients, 87 were available for the 12‐month follow‐up. Peri‐implant bone level change (?0.3 ± 0.5 mm vs ?0.3 ± 0.6 mm), plaque, and sulcus bleeding indices were not significantly different between TiZr and Ti Grade IV implants. Implant survival rates were 98.9 percent and 97.8 percent, success rates were 96.6 percent and 94.4 percent, respectively. Nineteen minor and no serious adverse events were related to the study devices. Conclusion: This study confirms that TiZr small‐diameter bone level implants provide at least the same outcomes after 12 months as Ti Grade IV bone level implants. The improved mechanical properties of TiZr implants may extend implant therapy to more challenging clinical situations.