拔牙区牙槽骨改建对牙齿移动的影响

拔牙区牙槽骨改建对牙齿的移动有直接的影响,国内外许多学得对此进行了研究。作者在该文中论述了拔牙区牙槽骨的改过程,牙齿向拔区移动的牙齿的移支方式,以及向拔牙移动对移移动牙和邻牙牙周状况的影响诸多问题,认为充分了解拔牙区牙槽骨的改过程和牙齿了向拔牙区移动的生物学机理,有助于临床医生有效控制牙齿移动,缩短疗程。     

拔牙区骨改建对邻牙移动速度的影响

目的　本研究通过对拔牙创的骨改建进程及矫治力对牙齿移动的影响进行研究,为临床医生选择理想的矫治力和牙齿移动时机,缩短矫治时间提供依据。方法　取SD大鼠36只,随机分为3组,全麻下拔除一侧上颌第一磨牙,3月后拔除另一侧上颌第一磨牙。在拔牙后不同的时间制作口内矫治器,分别以0·30、0·60、1·36 N的力牵上颌第二磨牙向拔牙区移动,分别在施力前及施力后的第1、3、5、7、10、14天拍摄X线片,利用图像处理技术, 测量牙齿移动距离,以置入的拔髓针校正放大率。结果　①牙齿向新鲜拔牙区移动的速度明显大于向已愈合拔牙区移动的速度。②无论向新鲜拔牙区移动还是向已经愈合的拔牙区移动,0·30 N力组牙齿移动的距离在各时间点与0·60 N、1·36 N力组牙齿移动的距离之间存在显著的统计学差异;而0·60 N与1·36 N力组牙齿移动的距离之间基本上从第5天开始差别不大。③加力后牙齿移动周期一般包括三个阶段:瞬时运动;迟滞期;后期移动阶段。大约在第14天时,由于矫治力衰减,牙齿停止移动。结论　①牙齿向新鲜拔牙区移动速度快,而向已经愈合的拔牙区移动速度慢。②在矫治过程中,中等力较为合适;即使使用较大的力,也不一定引起较大的牙齿移动。     

种植体骨结合与拔牙创愈合时间的相关性实验研究

目的：研究拔牙后创口愈合时间对种植体骨结合的影响,探讨拔牙后最佳种植体植入时间。方法：在拔除家犬的下颌双侧第二三前磨牙后不同时间植入种植体,3个月后处死动物观察种植体与拔牙窝之间新骨生成情况及密度并测量骨接触率。结果：0周组与3周组、6周组、9周组比较,差异有统计学意义（P〈0.05）,0周组的骨接触率明显低于3周组、6周组和9周组。3周组与9周组、6周组与9周组之间亦有非常显著性差异（P〈0.05）。6周组的骨接触率略高于3周组,但统计学分析无显著性差异（P〉0.05）。结论：在种植手术3个月时,即刻种植的骨接触率最低,拔牙3周、6周时种植的骨接触率无明显差异,拔牙后3周种植即能在短期内达理想骨结合。     

邻牙向拔牙区移动最佳时机选择的实验研究

目的　研究拔牙创愈合的生理过程和牙齿向拔牙区移动的生物学反应,探讨邻牙向拔牙区移动的最佳时机。方法　30只同源雄性SD大鼠分为5组,拔除上颌第一磨牙,在拔牙后不同的时间制作口内矫治器,牵第二磨牙向拔牙区移动。所有的大鼠分别在矫治器加力前两天和处死前两天给予四环素和钙黄绿素腹腔注射;制备硬组织切片,采用骨硬组织形态测量和计算机图像处理技术,对向处于不同愈合阶段的拔牙区移动牙齿时的骨改建参数进行定量分析。结果　①骨改建同时包括吸收和形成两个过程;②近中牙槽骨面(压力侧)骨吸收较远中 (张力侧)活跃,而远中牙槽骨面(张力侧)骨形成则较近中(压力侧)活跃;③骨形成参数、骨吸收参数均在拔牙后1 周存在一个峰值。结论　①拔牙后宜早期移动牙齿,以便充分利用拔牙创的骨改建优势;②其理想的移动时机为拔牙后1周左右。     

邻近拔牙创植入正畸微种植体骨界面愈合的组织学研究

目的 通过组织形态学观察和定量测定,比较拔牙创对种植体-骨界面愈合进程的影响,并对正畸微种植体骨整合的安全范围进行探讨。方法 12只雄性Beagle犬,按不同愈合时间段（1、3、8、12周）随机分成4组,建立邻近拔牙创植入正畸微种植体实验动物模型。在植入微种植体后愈合的第1、3、8、12周处死各组动物,制备含种植钉的硬组织切片,观察组织学形态,并测定微种植体-骨界面骨接触率（BIC）。结果 实验组和对照组在植入后第3周开始出现组织学变化的明显差异：实验组骨界面骨吸收活跃;对照组骨界面出现新生骨层,周边存在活跃成骨细胞。对照组在植入后前8周,BIC值随着时间的增加而增加。实验组BIC值在植入3周后有所下降,到第8周达到峰值（80.08％）,随后进入平台期。两组BIC的差异表现在植入后第3周：实验组BIC（44.35％）小于对照组（55.46％）,二者差异有统计学意义（P<0.01）。结论 拔牙创对微种植体周围骨重建进程会产生影响,早期表现为加重骨吸收,但在随后的时间里骨形成效应会迅速加强。     

拔牙矫治对牙弓宽度及基骨宽度的影响

目的 :研究拔牙矫治对牙弓宽度和基骨宽度的影响。方法 :在 2 0例AngleⅡ1拔牙病例矫治前后的石膏模型上 ,测量上下颌的牙弓长度、尖牙间牙弓宽度、第二前磨牙间牙弓宽度、第一磨牙间牙弓宽度以及相应的基骨宽度 ,测量结果数据用SPSS 10 .0进行统计学分析。结果 :上颌矫治后尖牙间牙弓宽度和基骨宽度明显增加 (P <0 .0 1) ,前磨牙间牙弓宽度和基骨宽度明显减小 (P <0 .0 1)。下颌矫治后尖牙间牙弓宽度不变而基骨宽度增加 (P <0 .0 5) ,第一磨牙间牙弓宽度不变而基骨宽度减小 (P <0 .0 1) ,前磨牙间牙弓宽度和基骨宽度均减小 (P <0 .0 1)。上下颌牙弓长度均减小 (P <0 .0 1)。结论 :牙弓越向远中移动 ,其牙弓宽度增大 ,越向近中移动 ,牙弓宽度减小 ,相应的基骨宽度也发生同样的变化。牙齿的转矩移动 ,会引起基骨宽度的改变。     

高压氧影响游离植骨种植体骨整合的组织学研究

目的：探讨高压氧能否促进种植体在非血管化新鲜自体游离移植骨上形成骨整合。方法：选用４只杂种成年狗,随机分成２组,每组２只,在狗下颌骨下缘各截取４ｃｍ×１．５ｃｍ大小的方形骨块,完全游离后原位植入,在植骨块上种入２个ＨＡ种植体。实验组动物在术后第 ３天开始进行高压氧（ＨＢＯ）治疗（２４．２ ｋＰａ、１．５ｈ／ｄ、５ｄ／周,共 ４周）,术后１０周处死 ４只动物,取含种植体的骨块,脱钙后腊包埋、切片、ＨＥ染色、组织学观察。结果：ＨＢＯ组种植体在移植骨上形成骨整合,种植体周围的新骨呈连续的骨界面。非ＨＢＯ组种植体界面呈不连续的新骨界面。结论：羟基磷灰石涂层种植体可在非血管化自体游离移植骨上形成骨整合,ＨＢＯ可以促进骨结合的形成。     

使用钙化人类异体骨增高拔牙窝的组织学评价

在牙齿拔除时实施拔牙窝增高术已被许多学者所推荐．因为成功的拔牙窝增高术可能会减少或避免将来进行牙槽嵴顶骨手术的需要。本文在此介绍一种拔牙窝增高术的操作过程．并描述其组织学、组织形态学的研究发现。5名患者（3名男性,2名女性;平均56岁）参加本研究．包括7个研究位点。应用可溶性多孔钙化的同种异体骨充填拔牙窝至骨嵴顶（位于软组织表面下2mm）,并应用生物可吸收性胶原伤口敷料覆盖创口表面。术后5～6个月．从拔牙窝中心提取活体组织进行检查。活检的组织学评价显示多孔钙化的同种异体骨移植区内．存在骨小梁的形成与重建,且无炎症征象。样本的组织形态学分析显示平均68．5％为新生骨,3．8％为剩余植入骨材料颗粒．27．7％为结缔组织或骨髓。此外．新生骨和结缔组织被观察到与剩余的植入骨材料紧密结合。这些数据显示人类钙化骨和可吸收性胶原伤口敷料的联合应用适用于拔牙窝增高术。然而,仍需要大样本量的临床对照研究进一步证实该发现。     

甘草锌对拔牙创临床愈合影响的研究

对上下颌第一、二磨牙拔除后分别采用甘草锌、硫酸锌及安慰剂口服,观察测量拔牙创的愈合情况。并于术后4d取拔牙创内组织,以光镜和电镜观察。研究结果提示:甘草锌和硫酸锌在含量相同的条件下对创伤愈合的促进作用前者优于后者;甘草锌对成纤维细胞有促进分裂增殖,合成纤维的作用,并有减轻炎症反应的免疫功能。     

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。     

Dynamics of bone tissue formation in tooth extraction sites. An experimental study in dogs

OBJECTIVES: The aim of the present experiment was to study events involved in the healing of marginal, central and apical compartments of an extraction socket, from the formation of a blood clot, to bone tissue formation and remodeling of the newly formed hard tissue. MATERIAL AND METHODS: Nine mongrel dogs were used for the experiment. The fourth mandibular premolars were selected for study and were divided into one mesial and one distal portion. The distal root was removed and the socket with surrounding soft and mineralized tissue was denoted "experimental unit". The dogs were killed 1, 3, 7, 14, 30, 60, 90, 120 and 180 days after the root extractions. Biopsies including the experimental units were demineralized in EDTA, dehydrated in ethanol and embedded in paraffin. Serial sections 7 microm thick were cut in a mesio-distal plane. From each biopsy, three sections representing the central part of the socket were selected for histological examination. Morphometric measurements were performed to determine the volume occupied by different types of tissues in the marginal, central and apical compartments of the extraction socket at different intervals. RESULTS: During the first 3 days of healing, a blood clot was found to occupy most of the extraction site. After seven days this clot was in part replaced with a provisional matrix (PCT). On day 14, the tissue of the socket was comprised of PM and woven bone. On day 30, mineralized bone occupied 88% of the socket volume. This tissue had decreased to 15% on day 180. The portion occupied by bone marrow (BM) in the day 60 specimens was about 75%, but had increased to 85% on day 180. CONCLUSION: The healing of an extraction socket involved a series of events including the formation of a coagulum that was replaced by (i) a provisional connective tissue matrix, (ii) woven bone, and (iii) lamellar bone and BM. During the healing process a hard tissue bridge--cortical bone--formed, which "closed" the socket.     

Histomorphometric study on the effects of age on orthodontic tooth movement and alveolar bone turnover in rats

The aim of this study was to investigate, in a rat model, the effects of age on the amount of tooth movement and concomitant changes in alveolar bone turnover activity adjacent to orthodontically treated tooth roots. Rats (n = 48) of four different age groups (10, 30, 50, and 80 wk of age) were used in the experiment. Maxillary first molars were tipped mesially with a nickel titanium alloy coil-spring for 2 wk by a continuous force of 10 cN. Forty-eight age-matched untreated rats were used as controls. The changes in alveolar bone turnover were assessed histomorphometrically. Two weeks after the start of tooth movement, the amount of tooth movement was found to decrease with age and was significantly different among the four age groups. The histomorphometric study demonstrated that, in all experimental groups, turnover of alveolar bone increased significantly compared with that of each age-matched untreated group. However, the rate of increase decreased in an age-related manner. These results suggest that the age-dependent decrease in alveolar bone turnover activity, in response to mechanical forces, may negatively affect the amount of tooth movement.     

羟基磷灰石人工骨微粒植入牙槽窝的临床应用研究

目的 :研究拔牙后即刻植入羟基磷灰石微粒人工骨预防术后并发症及牙槽骨吸收的临床疗效。方法 :3 1例患者拔牙后牙槽窝内即刻植入羟基磷灰石微粒人工骨 ,术后对患者拔牙创出血、干槽症、牙槽嵴高度等项进行观察并于术后、术后 4周、12周复诊进行临床及X线片检查。结果 :3 1例患者创口愈合良好 ,术后无出血、无干槽症发生 ,X线片见牙槽窝内羟基磷灰石存在 ,牙槽高度恢复良好。结论 :拔牙创内即刻植入羟基磷灰石人工骨不影响创口愈合 ,能很好地维持牙槽嵴高度 ,为人工义齿的修复创造条件     

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目的比较微创拔牙技术与传统凿骨劈冠法拔除下颌低位埋伏阻生智齿的临床疗效。方法选择2012年8月至2013年10月河南省濮阳市油田总医院口腔颌面外科门诊300例下颌低位埋伏阻生智齿患者,按就诊顺序分为微创组与锤凿组各150例。微创组采用微创拔牙器械及微创拔牙技术拔除下颌低位埋伏阻生智齿;锤凿组采用传统的拔牙器械及凿骨劈冠法拔除下颌低位埋伏阻生智齿。对两组手术时间及术中、术后并发症进行比较观察和统计学分析。结果微创组手术时间[（18．0±6.3）min]比锤凿组[（37．0±8．2）min]显著缩短,差异有统计学意义（P〈0．05）;微创组术后疼痛、肿胀、张口受限、干槽症等并发症发生率明显低于锤凿组,差异有统计学意义（P〈0．05）。结论使用微创拔牙技术拔除下颌低位埋伏阻生智齿,手术时间短,创伤小,可明显减少术后并发症,临床疗效优于传统凿骨劈冠拔除法。     

Comparative study of gene expression during tooth eruption and orthodontic tooth movement in mice

Objective:  The aim of this study was to understand tooth eruption by comparing the gene expression during tooth eruption and orthodontic tooth movement (OTM).
Materials and methods:  Orthodontic force was applied on maxillary molars for 2, 4, 7 and 14 days to study tooth movement. Mice at PN 0, 7, 10, 15 and 21 were fixed to observe tooth eruption. Comparative study of two procedures was assessed by haematoxylin and eosin, tartrate-resistant acid phosphatase staining and in situ hybridization for matrix metalloproteinase ( Mmp ) 2 , 13 , bone sialoprotein ( Bsp ) and osteocalcin ( Ocn ).
Results:  Tartrate-resistant acid phosphatase activity and expression of Mmp2 , 13 were obviously detectable in the compression region during OTM. They were also identified in the occlusal and apical region of alveolar bone during tooth eruption. Strong expression of Bsp and Ocn was detectable at the tension side during OTM. These genes were also expressed in the inner lateral region of alveolar bone adjacent to the tooth, but absent in the inner surface of the occlusal and root apical regions during tooth eruption.
Conclusion:  The process of alveolar bone metabolism during developmental eruption and OTM shares the same mechanism. Internal force, as the orthodontic force for OTM, may be initiating factor for tooth eruption.     

Analysis of the pattern of the alveolar ridge remodelling following single tooth extraction

Introduction: Tooth extraction is followed by marked osseous changes of the residual alveolar ridge including severe bone alterations both in height and in width. However, such remodelling could jeopardize the subsequent implant insertion for two main reasons. Firstly, the absence of adequate bone levels makes implant placement impossible; secondly, aesthetic problems in the fabrication of implanto‐supported restoration could be caused by serious bone re‐absorption. Thus, it is of crucial importance that the dental surgeon knows how the alveolar crest changes when a single tooth has been removed. The aim of this study was to evaluate the pattern of alveolar crest remodelling observed in a single intercalated area of tooth extraction after at least a period of 6 months of healing, using standardized photos of model casts. Material and methods: Among the patients who were treated for a single intercalated tooth extraction during the last 2 years at the department of dentistry at Versilia Hospital, Lido di Camaiore (Lucca), Italy, we selected 50 patients. The amount of alveolar crest remodelling was assessed on standardized photos of study models. All measurement were recorded on an Excel sheet (Excel, Windows XP^®) and each value was multiplied by the enlargement index so that true values of re‐absorption could be obtained. Finally, we have calculated the percentage of amount of alveolar crest remodelling and shifting of alveolar crest. Results: We calculated the percentage of buccal remodelling and alveolar crest shift. The buccal re‐absorption was 19.4±9.4% at mesial point, 39.1±10.4% at midpoint and 20.3±10.7% at distal level. Moreover, the shift of the alveolar crest was 59.1±11.2% at mesial point, 64.8±10.5% at the midpoint and 56±12.5% at distal point. Conclusions: This study confirmed that buccal wall tends to re‐absorb after the extraction according to a specific pattern. Thus, the re‐absorption at the midpoint represent the double of bone loss at the distal and the mesial points. Furthermore, we have observed first how the alveolar crest shifts placing along the more lingual/palatal line which divides the original alveolar crest into three parts. To cite this article:
Covani U, Ricci M, Bozzolo G, Mangano F, Zini A, Barone A. Analysis of the pattern of the alveolar ridge remodelling following single tooth extraction.
Clin. Oral Impl. Res. 22 , 2011; 820–825
doi: 10.1111/j.1600‐0501.2010.02060.x     

Modeling and remodeling of human extraction sockets

Introduction: The available studies on extraction wound repair in humans are affected by significant limitations and have failed to evaluate tissue alterations occurring in all compartments of the hard tissue defect.
Aim: To monitor during a 6-month period the healing of human extraction sockets and include a semi-quantitative analysis of tissues and cell populations involved in various stages of the processes of modeling/remodeling.
Material and Methods: Twenty-seven biopsies, representative of the early (2–4 weeks, n =10), intermediate (6–8 weeks, n =6), and late phase (12–24 weeks, n =11) of healing, were collected and analysed.
Results: Granulation tissue that was present in comparatively large amounts in the early healing phase of socket healing, was in the interval between the early and intermediate observation phase replaced with provisional matrix and woven bone. The density of vascular structures and macrophages slowly decreased from 2 to 4 weeks over time. The presence of osteoblasts peaked at 6–8 weeks and remained almost stable thereafter; a small number of osteoclasts were present in a few specimens at each observation interval.
Conclusions: The present findings demonstrated that great variability exists in man with respect to hard tissue formation within extraction sockets. Thus, whereas a provisional connective tissue consistently forms within the first weeks of healing, the interval during which mineralized bone is laid down is much less predictable.     

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提要：拔牙的微创技术开启了拔牙的新时代,使拔牙这一古老的手术更加走向标准化、微创化、舒适化和个性化。目前,微创拔牙的理念和技术在国内的应用和推广亟待提高。本文对微创拔牙的发展、微创拔牙器械的进步、微创拔牙技术的应用等做一述评,为进一步在国内推广微创拔牙的理念和应用微创拔牙的技术抛砖引玉。