胰岛素样生长因子I对糖尿病大鼠拔牙后牙槽骨改建的影响

目的研究胰岛素样生长因子I（IGF—I）对糖尿病大鼠拔牙后牙槽骨改建的影响,为糖尿病性牙周病的治疗提供依据。方法对四氧嘧啶诱导的糖尿病大鼠拔牙后进行胰岛素和胰岛素样生长因子I治疗,通过X线、组织切片苏木精一伊红染色和四环素双标记的方法观察牙槽骨改建情况。结果与正常组相比,糖尿病大鼠拔牙创骨愈合减慢,骨形成减少,牙槽骨高度和牙槽骨骨形成率显著降低。IGF—I的治疗不仅能控制糖尿病大鼠的血糖保持在正常范围内,还可以增加牙槽骨高度和提高骨形成率。结论IGF-I的治疗可以促进糖尿病大鼠拔牙创骨愈合和增加骨形成量,且与胰岛素治疗之间没有明显差别。     

Effects of alendronate on bone healing after tooth extraction in rats

Oral Diseases (2010) 16 , 674–685 Objectives: Tooth extraction has been identified as an important risk factor for bisphosphonate‐induced osteonecrosis of the jaw. Therefore, the main goal of this study was to determine the effects of alendronate on healing of the extraction socket and on interdental alveolar bone after tooth extraction in rats. Materials and methods: Animals were injected subcutaneously with vehicle or alendronate for 3–4 weeks before the first mandibular molar was extracted and these treatments were continued during post‐extraction periods of 10, 21, 35 and 70 days. Mandibles were processed to evaluate healing of the extraction socket and adjacent alveolar bone by assessing bone formation, bone resorption and vascularity by histomorphometric techniques. Results: Alendronate decreased new woven bone formation, blood vessel area, perimeter and number in the extraction socket at 10 days postextraction, but not at later time points. Furthermore, alendronate‐treated rats had increased interdental alveolar bone volume and height only at 10 days postextraction. In addition, a 2.5‐fold increase in the percentage of empty osteocyte lacunae was found in alveolar bone of alendronate‐treated rats only at 10 days postextraction. Conclusions: Alendronate transiently decreases bone formation and vascularity in the extraction socket and delays the removal of interdental alveolar bone after tooth extraction in rats.     

The influence of short-term diabetes mellitus and insulin therapy on alveolar bone loss in rats

BACKGROUND: It is well known that the multiple direct and indirect consequences of hyperglycemia in diabetic individuals have been linked to a number of abnormal host effector mechanisms that could lead to an increased risk of developing periodontal disease. OBJECTIVE: The aim of this study was to investigate the effect of short-term experimental diabetes and insulin therapy on the severity of alveolar bone loss in rats, and the effect of experimental periodontitis on glycemic control. METHODS: Seventy-two male Wistar rats were divided into four groups: group I animals were submitted to dental ligature around lower right first molars (ligated); group II consisted of streptozotocin (STZ)-diabetic, ligated rats; group III represented STZ-diabetic, unligated rats; and group IV consisted of insulin-treated (6 U/day), STZ-diabetic, ligated rats. Blood glucose of all diabetic rats was monitored at regular intervals. Standardized digital radiographs were taken after killing at 7, 15 and 30 days to measure the amount of bone loss about the mesial root surface of the first molar tooth in each rat. Results: No significant (p < 0.05) changes in plasma glucose levels of insulin-treated diabetic rats were found among the different examinations after the beginning of insulin therapy. Rats from group II showed significantly greater increases in mean plasma glucose levels at 15 and 30 days after ligature placement compared with rats from group III (p < 0.05). Furthermore, in spite of the significant alveolar bone loss progression that was observed in groups I, II and IV (p < 0.00001; two-way anova), no significant differences among these groups regarding the severity of bone loss (p = 0.77) and no significant interaction between treatment group and time (p = 0.81) were found. CONCLUSIONS: Within the limits of this study, it can be suggested that the severity of periodontal disease was not affected by short-term diabetes, and that experimental periodontitis increased blood glucose levels in uncontrolled diabetic rats.     

Alveolar bone remodeling around immediate implants placed in accordance with the extraction socket classification: a three-dimensional microcomputed tomography analysis

Background: Previous studies assessed bone remodeling after a single tooth extraction; however, the effect of multiple contiguous teeth extractions around immediate implant remains unknown. The aim of this microcomputed tomographic investigation is to analyze the alveolar bone remodeling around immediate implants placed in accordance with the extraction socket classification (ESC). Methods: Under general anesthesia, 10 beagle dogs underwent atraumatic tooth extractions. Animals were randomly divided into three groups, with 16 sites per group: 1) ESC‐1, single tooth extraction; 2) ESC‐2, two contiguous teeth extraction; and 3) ESC‐3, more than two contiguous teeth extractions. Immediate implants were inserted in each socket, and postoperative plaque control measures were undertaken. After euthanasia, the jaw segments were evaluated for bone thickness, marginal bone loss (MBL), and bone‐to‐implant contact (BIC) using microcomputed tomography. Results: The mean buccal bone thickness (P <0.05) and MBL (P <0.05) was compromised in jaws in ESC‐3 compared to those in ESC‐1 and ESC‐2. The BIC was significantly higher among jaws in ESC‐1 compared to those in ESC‐2 and ESC‐3 (P <0.05). There was no significant difference in the buccal bone thickness, MBL, and BIC among the groups in the maxilla and mandible. Lingual bone remodeling did not reveal any significant differences among the groups in either jaw. Conclusion: Buccal bone remodeling is significantly more extensive around immediate implants placed in multiple contiguous tooth extraction sites compared to immediate implants placed in single tooth extraction sites.     

胰岛素对糖尿病大鼠种植体周骨组织代谢影响的研究

目的 探索胰岛素治疗对于高糖环境下种植体周骨组织代谢及种植体-骨结合的影响.方法 构建糖尿病大鼠模型,在大鼠股骨植入钛种植体,并给予胰岛素治疗;同时通过成骨细胞培养,体外构建高糖环境,给予胰岛素干预.结果 糖尿病大鼠种植体周骨组织形成和矿化明显降低,胰岛素干预治疗能起到明显的改善作用;此外,胰岛素干预后成骨细胞中胰岛素受体表达明显增加.结论 胰岛素也许通过胰岛素信号通路调控高糖环境中成骨细胞功能,改善骨组织的形成和矿化.     

Connective tissue growth factor expressed in rat alveolar bone regeneration sites after tooth extraction

OBJECTIVE: To understand bone regeneration process after tooth extraction could be a clue to develop a new strategy for alveolar bone reconstruction. Recently, accumulated evidences support that connective tissue growth factor (CTGF) is implicated in tissue repair of many tissues. In this study, we investigated the spatial and temporal expression of CTGF in the rat tooth extraction sockets. DESIGN: Five weeks old wild type male rats (weighing 120 g) were used for this experiment. Expression of CTGF was determined by immunohistochemistry and in situ hybridization in the rat upper molar tooth extraction sockets at 2, 4, 7, 10 and 14 days after tooth extraction. RESULTS: CTGF was expressed strongly in the endothelial cells migrating into the granulation tissue at the bottom of the sockets during 4 days after tooth extraction. During the reparative process, no apparent chondrocyte-like cell appeared in the sockets, while osteoblast-like cells proliferated in the sockets with low CTGF expression at 7, 10, 14 days after extraction. As expected, no staining was observed with the preimmune rabbit IgG and CTGF sense probe. CTGF may play an important role in angiogenesis and granulation tissue formation specifically at early healing stage after tooth extraction to initiate alveolar bone repair. CONCLUSION: CTGF was expressed at early healing stage of the rat tooth extraction wound.     

Low‐energy laser irradiation accelerates the velocity of tooth movement via stimulation of the alveolar bone remodeling

Authors – Yoshida T, Yamaguchi M, Utsunomiya T, Kato M, Arai Y, Kaneda T, Yamamoto H, Kasai K Introduction – Previously, the authors have reported the acceleration of tooth movement and osteoclastogenesis on the pressure site in an experimental tooth movement model by low‐energy laser irradiation (LELI), which stimulated the RANK/RANKL system and c‐fms/macrophage colony‐stimulating factor system. However, the effect of LELI on osteogenesis on the tension site is not known clearly. Moreover, the temporal changes in alveolar bone during tooth movement have not been investigated as yet. Therefore, the present study was designed to examine the effects of LELI on alveolar bone remodeling during experimental tooth movement, and observe the temporal bone mineral density (BMD) using micro‐computed tomography (μCT). Materials and methods – To induce experimental tooth movement in rats, 10 g force was applied to the upper right first molar with Nickel titanium closed‐coil. Next, a gallium‐aluminum‐arsenide (Ga‐Al‐As) diode laser was used to irradiate the area around the moved tooth, and BMD and the amount of tooth movement were measured by μCT scanning for 21 days. Histopathological examination was also performed. Results – The amount of tooth movement in the LELI group was significantly greater than in the non‐irradiation group by the end of the experimental period. Further, compared with the non‐irradiation group, the fall of BMD was less in the LELI group. Conclusion – These findings suggest that LELI accelerates the velocity of tooth movement via stimulation of the alveolar bone remodeling.     

Alterations of collagen-I, MMP-1 and TIMP-1 in the periodontal ligament of diabetic rats under mechanical stress

Zhang L, Li X, Bi L‐J. Alterations of collagen‐I, MMP‐1 and TIMP‐1 in the periodontal ligament of diabetic rats under mechanical stress. J Periodont Res 2011; 46: 448–455. ©2011 John Wiley & Sons A/S Background and Objective: The present study assessed effects of hyperglycemia on production of proteins involved in remodeling of the periodontal ligament under mechanical stress. Material and Methods: Forty‐eight Sprague–Dawley rats were randomly divided into the following two groups: nondiabetic (ND) and diabetes induced (DI; n = 24 each group). Diabetes was induced in the DI group by a single dose of streptozotocin, and saline solution was injected in the ND group. Rats were killed 1–14 d after induction of mechanical pressure (50 g) on the first upper left molar. Alterations of collagen type I (Col‐I), MMP‐1 and TIMP‐1 in the upper left periodontal ligament of these rats were measured immunohistochemically and compared with those on the contralateral side of the same rat (control; no force induction). Results: The DI group showed a decrease in Col‐I and an increase in MMP‐1 compared with the ND group. Both Col‐I and MMP‐1 increased in both groups, whereas TIMP‐1 was decreased following mechanical pressure. The DI group exhibited a longer duration of increased MMP‐1 and MMP/TIMP ratio compared with the ND group. Conclusion: Diabetes affects proteins involved in remodeling of periodontal ligament during mechanical pressure. This may delay the reconstruction and remodeling of periodontal ligament in diabetic individuals.     

Orally Administered Liposomal Lactoferrin Inhibits Inflammation‐Related Bone Breakdown Without Interrupting Orthodontic Tooth Movement

Background: Bovine lactoferrin (bLF) modulates the production of tumor necrosis factor‐alpha (TNF‐α) and inhibits alveolar bone breakdown associated with periodontitis. This study is designed to examine the effects of orally administered liposomal bLF (LbLF) on orthodontic force (OF)‐induced alveolar bone remodeling during experimental tooth movement. Methods: Two groups of male Wistar rats were treated with either LbLF or control solution in drinking water 7 days before OF application. Lipopolysaccharide (LPS) was injected into the gingival sulcus in half the rats in each group. Thus, four groups: OF, OF+LbLF, OF+LPS, and OF+LPS+LbLF were established. Results: Orally administered LbLF significantly reduced apical migration of junctional epithelium in the OF and OF+LPS groups. In OF+LPS, osteoclast number in the alveolar crestal area was increased by LPS treatment, whereas osteoclast number was significantly reduced in OF+LPS+LbLF through suppression of TNF‐α production. Osteoclastic induction in the middle part, mainly from OF application, was not affected by LbLF administration. Inhibition of tooth movement was not induced by LbLF. Conclusions: Orally administered LbLF significantly inhibits LPS‐induced alveolar bone resorption but not OF‐induced bone remodeling. LbLF could be a potent therapeutic and preventive agent to control periodontal inflammation in patients undergoing orthodontic treatment.     

Effect of Single and Contiguous Teeth Extractions on Alveolar Bone Remodeling: A Study in Dogs

Background: Tooth extraction is associated with dimensional changes in the alveolar ridge. The aim was to examine the effect of single versus contiguous teeth extractions on the alveolar ridge remodeling. Material and Methods: Five female beagle dogs were randomly divided into three groups on the basis of location (anterior or posterior) and number of teeth extracted – exctraction socket classification: group 1 (one dog): single‐tooth extraction; group 2 (two dogs): extraction of two teeth; and group 3 (two dogs): extraction of three teeth in four anterior sites and four posterior sites in both jaws. The dogs were sacrificed after 4 months. Sagittal sectioning of each extraction site was performed and evaluated using microcomputed tomography. Results: Buccolingual or palatal bone loss was observed 4 months after extraction in all three groups. The mean of the alveolar ridge width loss in group 1 (single‐tooth extraction) was significantly less than those in groups 2 and 3 (p < .001) (multiple teeth extraction). Three‐teeth extraction (group 3) had significantly more alveolar bone loss than two‐teeth extraction (group 2) (p < .001). The three‐teeth extraction group in the upper and lower showed more obvious resorption on the palatal/lingual side especially in the lower group posterior locations. Conclusion: Contiguous teeth extraction caused significantly more alveolar ridge bone loss as compared with when a single tooth is extracted.     

炎症对大鼠牙槽骨骨重建的影响

目的：了解拔牙窝残存炎性组织对拔牙后骨重建过程的影响。方法：健康成年SD大鼠56只,6只用于牙齿折裂炎症感染模型建立的预实验,X线片及病理确定8周为根周存在囊肿或肉芽肿炎症感染的时间点。50只大鼠建立下颌左右第一磨牙根周感染模型,8周后根据X线根尖片取36只根尖部炎症明显的大鼠,根据自身对照原则,左侧实验组牙齿拔除后不刮治,右侧对照组刮除感染组织。术后4周、8周、12周分别进行游标卡尺测量、X线影像学检查和组织学检查,评价拔牙后左右侧牙槽骨骨重建是否有差异。结果：术后4周、8周、12周两组牙槽嵴颊舌侧高度差存在差异,实验组颊舌侧高度差值较大,术后4周、8周实验组新骨形成明显少于对照组。结论：炎症组织使拔牙后颊侧牙槽嵴高度明显下降,拔牙窝的前期修复速度减慢。     

Appliance‐induced osteopenia of dentoalveolar bone in the rat: effect of reduced bone strains on serum bone markers and the multifunctional hormone leptin

To understand, in greater detail, the molecular mechanisms regulating the complex relationship between mechanical strain and alveolar bone metabolism during orthodontic treatment, passive cross‐arch palatal springs were bonded to the maxillary molars of 6‐wk‐old rats, which were killed after 4 and 8 d. Outcome measures included serum assays for markers of bone formation and resorption and for the multifunctional hormone leptin, and histomorphometry of the inter‐radicular bone. The concentration of the bone‐formation marker alkaline phosphatase (ALP) was significantly reduced at both time points in the appliance group, accompanied by a 50% reduction in inter‐radicular bone volume; however, osteocalcin (bone Gla protein) levels remained unaffected. Bone collagen deoxypyridinoline (DPD) crosslinks increased 2.3‐fold at 4 d only, indicating a transient increase in bone resorption; in contrast, the level of the osteoclast‐specific marker, tartrate‐resistant acid phosphatase 5b (TRACP 5b), was unchanged. Leptin levels closely paralleled ALP reductions at both time points, suggesting an important role in the mechanostat negative‐feedback loop required to normalize bone mass. These data suggest that an orthodontic appliance, in addition to remodeling the periodontal ligament (PDL)–bone interface, may exert unexpected side‐effects on the tooth‐supporting alveolar bone, and highlights the importance of recognizing that bone strains can have negative, as well as positive, effects on bone mass.     

The Effect of Leptin on Rat Maxillary Alveolar Bone under Mechanical Stimuli

Mechanical stress is known to play an important role in bone remodeling and homeostasis, by influencing processes of bone formation and bone resorption. Some hormones have been shown to influence not only bone homeostasis but also mechanical stress-induced bone remodeling. For example, leptin, a hormone secreted by adipocytes that controls mammal's appetite, has been suggested to regulate bone volume. Here, we have investigated the effects of leptin on the remodeling of alveolar bone induced by experimental tooth movement in leptin receptor-defective Wistar fatty rats. Seven days after applying tractive force on a right maxillary first molar, a larger tooth displacement was observed in heterozygous (fa/+) compared to wild-type (+/+) animals. Histomorphometry demonstrated a significantly elevated osteoclast number in the alveolar bone of heterozygous (fa/+) (p<0.05) when compared to that in wild-type (+/+) rats, indicating that leptin receptor deficiency enabled rapid orthodontic tooth movement by accelerated bone resorption. Our findings suggested that leptin could influence mechanical stress-induced bone remodeling.     

牙体硬组织表面电位影响骨改建的实验研究

目的研究牙体硬组织表面电位与骨生长改建的关系。方法将人牙釉质试件、牙釉质-牙本质试件、牙本质-牙骨质试件和多孔羟基磷灰石试件各25个植入25只家兔胫骨中,通过组织病理学、酶组织化学染色和四环素荧光标记方法,在术后不同时间段观察、评价各试件正负极侧的家兔胫骨骨组织改建情况。结果光镜观察各时间段牙体试件的负极侧成骨较正极侧活跃,破骨细胞数量计数正极侧较负极侧多(P<0.01)。四环素荧光标记显示负极侧荧光面积多于正极侧(P<0.05)。结论牙体硬组织表面电位可影响骨改建:荷正电的牙釉质面促进骨的吸收破坏,荷负电的牙骨质面促进成骨。牙齿过萌与无牙颌牙槽骨萎缩可能与此有关。     

N‐acetylcysteine decreases alveolar bone loss on experimental periodontitis in streptozotocin‐induced diabetic rats

Toker H, Ozdemir H, Balc? H, Ozer H. N‐acetylcysteine decreases alveolar bone loss on experimental periodontitis in streptozotocin‐induced diabetic rats. J Periodont Res 2012; 47: 793–799. © 2012 John Wiley & Sons A/S Background and Objective: The purpose of this study was to evaluate the morphometric and histopathological changes associated with experimental periodontitis in diabetic rats in response to systemic administration of N‐acetylcysteine (NAC), a sulfhydryl‐containing thiol antioxidant. Material and methods: Sixty Wistar rats were divided into six experimental groups: nonligated (NL) group; ligature‐only (L) group; streptozotocin‐only (STZ) group; STZ and ligature (STZ + L) group; and systemic administration of NAC and ligature (70 and 100 mg/kg body weight per day, respectively) (NAC70 and NAC100 groups). Diabetes mellitus was induced by 60 mg/kg of streptozotocin. Silk ligatures were placed at the gingival margin of the lower first molars of the mandibular quadrant. The study duration was 30 d and the animals were killed at the end of this period. Changes in alveolar bone levels were clinically measured and tissues were histopathologically examined to assess the differences among the study groups. Results: At the end of the 30‐d study period, alveolar bone loss was significantly higher in the STZ + L group compared with the other groups (p < 0.05). Also, alveolar bone loss in all the NAC groups was significantly lower than in the STZ + L and L groups (p < 0.05). The osteoblastic activity in the NAC100 group was significantly higher than in the other groups (p < 0.05). Conclusion: Within the limits of this study, it can be suggested that NAC, when administered systemically, prevents alveolar bone loss in the diabetic rat model.     

Compensatory bone formation in young and old rats during tooth movement

The aim of this study was to investigate compensatory lingual alveolar bone formation during tooth movement in young and old rats, using the vital bone marker tetracycline. Wistar male rats were separated into the following groups: 13-week-old rats without appliances (13C: control, n = 5), 60-week-old rats without appliances (60C: control, n = 5), 13-week-old rats with appliances (13E: experimental, n = 10), and 60-week-old rats with appliances (60E: experimental, n = 10). The upper first molars of the 13E and 60E groups were moved lingually using fixed appliances. On the third day of tooth movement, tetracycline (TC) was intra-peritoneally injected in all animals including the controls. On the 21st day of tooth movement, the animals were killed and unfixed, and undecalcified, 5-microm frozen frontal sections of the rat first molar areas in both control and experimental groups were examined under light and fluorescent microscopes. In the 13C group without tooth movement, tetracycline labelling lines were obvious in the alveolar crest, apical areas, and interradicular septum, indicating vertical alveolar bone growth. However, in the 60C control group, tetracycline labelling was almost undetectable throughout the alveolar bone. Although the lingual alveolar crest was resorbed from the periodontal side after lingual tooth movement, the sharp, bright labelling lines were still present from the crest to the lingual periosteal alveolar bone in the 13E group. In the 60E group the lines appeared in the lingual periosteal alveolar bone containing the crest, indicating considerable new bone formation. The results indicate that compensatory bone formation occurs in the alveolar crest area and, consequently, alveolar bone height is maintained, even in aged rats.     

糖尿病大鼠牙槽骨骨密度与全身骨密度变化的相关实验研究

目的比较雌、雄性糖尿病大鼠牙槽骨骨密度的改变以及雄性糖尿病大鼠全身骨密度的改变。方法将40只Wistar大鼠分为糖尿病组（雌、雄性大鼠各15只）和对照组（雌、雄性大鼠各5只）。腹腔注射链脲佐菌素（STZ）制备糖尿病大鼠模型,检测糖尿病组和对照组大鼠血糖、血清胰岛素和骨代谢指标,检测下颌牙槽骨、股骨和腰椎的骨密度。结果对照组和糖尿病组雄性大鼠下颌牙槽骨骨密度均高于雌性大鼠（P<0.05）;糖尿病组雌、雄性大鼠下颌牙槽骨骨密度分别低于对照组雌、雄性大鼠（P<0.05）。对照组雄性大鼠的骨密度由高至低依次为股骨、下颌牙槽骨、腰椎;糖尿病组雄性大鼠的骨密度由高至低依次为下颌牙槽骨、股骨、腰椎。结论糖尿病雌、雄性大鼠下颌牙槽骨发生了糖尿病性骨质疏松,且雌性大鼠骨质疏松更严重;雄性糖尿病大鼠下颌牙槽骨、股骨和腰椎骨密度较对照组低,下颌牙槽骨骨密度变化与股骨和腰椎的变化相一致,或是糖尿病组大鼠下颌牙槽骨骨密度变化滞后于股骨和腰椎骨密度的变化。     

Effect of socket preservation therapies following tooth extraction in non-molar regions in humans: a systematic review

Objective: To assess, based on the existing literature, the benefit of socket preservation therapies in patients with a tooth extraction in the anterior or premolar region as compared with no additional treatment with respect to bone level. Material and methods: MEDLINE‐PubMed and the Cochrane Central Register of controlled trials (CENTRAL) were searched till June 2010 for appropriate studies, which reported data concerning the dimensional changes in alveolar height and width after tooth extraction with or without additional treatment like bonefillers, collagen, growth factors or membranes. Results: Independent screening of the titles and abstracts of 1918 MEDLINE‐PubMed and 163 Cochrane papers resulted in nine publications that met the eligibility criteria. In natural healing after extraction, a reduction in width ranging between 2.6 and 4.6 mm and in height between 0.4 and 3.9 mm was observed. With respect to socket preservation, the freeze‐dried bone allograft group performed best with a gain in height, however, concurrent with a loss in width of 1.2 mm. Conclusion: Data concerning socket preservation therapies in humans are scarce, which does not allow any firm conclusions. Socket preservation may aid in reducing the bone dimensional changes following tooth extraction. However, they do not prevent bone resorption because, depending on the technique, on the basis of the included papers one may still expect a loss in width and in height. To cite this article:
Ten Heggeler JMAG, Slot DE, Van der Weijden GA. Effect of socket preservation therapies following tooth extraction in non‐molar regions in humans: a systematic review.
Clin. Oral Impl. Res. 22 , 2011; 779–788
doi: 10.1111/j.1600‐0501.2010.02064.x.
     

新型硅磷酸钙用于大鼠拔牙位点保存的早期成骨性能研究

目的    通过SD大鼠拔牙窝模型研究硅磷酸钙（CPS）骨粉的体内成骨性能。方法    选择45只6周龄SD大鼠,全麻下拔除右侧上颌2颗磨牙后按照拔牙窝充填材料随机分为3组,每组15只。CPS组：拔牙后于拔牙窝内放入CPS骨粉,用Bio-Gide膜覆盖拔牙窝并缝合;Bio-Oss组：拔牙后于拔牙窝内放入Bio-Oss骨粉,用Bio-Gide膜覆盖拔牙窝并缝合;对照组：拔牙后不放置充填材料,直接用Bio-Gide膜覆盖拔牙窝并缝合。于术后2、4、8周分别处死每组大鼠5只并取材上颌骨,采用影像学和组织学检测方法测量并评价拔牙窝牙槽骨愈合情况。结果  所有大鼠样本在术后2、4、8周这3个时间点的拔牙位点骨体积分数、骨密度及骨小梁厚度均随着术后时间延长而增大。术后4周时,Bio-Oss组拔牙位点骨体积分数、骨小梁厚度大于CPS组和对照组（P < 0.05）。术后8周时,CPS组的拔牙位点骨体积分数、牙槽骨宽度、牙槽骨高度及骨密度略高于Bio-Oss组和对照组, CPS组的骨小梁厚度介于Bio-Oss组和对照组之间,但3组间各指标的差异均无统计学意义（均P > 0.05）。组织学观察发现,术后8周CPS组和Bio-Oss组仅可见少量的未降解材料,周围有较多新骨形成,骨质较致密。结论    CPS在体内具有良好的促成骨能力和降解性能,可有效减少拔牙后牙槽骨萎缩,具有作为位点保存充填材料的潜力。     

成骨诱导剂对拔牙创愈合的影响

目的 探讨以明胶海绵为载体,地塞米松、维生素C和β-甘油磷酸钠组成的成骨诱导剂对拔牙创愈合和牙槽嵴形态改建的影响。方法选用50只家兔,拔除双侧上颌第一前磨牙,右侧拔牙创内填入载有成骨诱导剂的明胶海绵,作为实验侧;左侧填入空载明胶海绵,作为对照侧。拔牙后第1、2、4、8、12周各处死10只动物,取双侧牙槽骨标本,拍摄X线片,并测量骨缺损区新骨密度;用组织学方法评价拔牙创愈合情况;并于12周时,测量拔牙区牙槽嵴高度吸收值。结果X线片骨密度测量显示：术后2、4、8、12周,实验侧骨密度值均高于对照侧,差异有统计学意义（P<0.01）。组织学检查显示：实验侧拔牙创内成骨现象较对照侧早,成骨细胞分化和增殖更活跃。
12周时实验侧牙槽嵴高度吸收值小于对照侧,差异有统计学意义（P<0.01）。结论 由地塞米松、β-甘油磷酸钠和维生素C组成的成骨诱导剂能促进拔牙创愈合,加速成骨和骨改建。