Binzhou Medical College, School of Stomatology, Shandong, China.
Central Laboratory of Jinan Stomatological Hospital, Jinan Key Laboratory of Oral Tissue Regeneration, Department of Endodontics, Shandong Province, China.
J Appl Oral Sci. 2022 Jul 8;30:e20220010. doi: 10.1590/1678-7757-2022-0010. eCollection 2022.
Characterizations of rat mandibular second molar extraction socket with significantly different buccal and lingual alveolar ridge width remain unclear.
To observe alterations in the alveolar ridge after extraction of mandibular second molars, and to examine processes of alveolar socket healing in an experimental model of alveolar ridge absorption and preservation.
Eighteen Wistar rats were included and divided into six groups regarding healing time in the study. Bilateral mandibular second molars were extracted. The rats with tooth extraction sockets took 0, 1.5, 2, 3, 4 and 8 weeks of healing. Histological observation, tartrate-resistant acidic phosphatase (TRAP) staining, Masson's trichrome staining, immunohistochemical staining and micro-computed tomography (micro-CT) were applied to estimate alterations in the alveolar ridge.
Different buccal and lingual alveolar ridge width led to different height loss. Lingual wall height (LH) decreased significantly two weeks after tooth extraction. Buccal wall height rarely reduced its higher ridge width. From two to eight weeks after extraction, bone volume (BV/TV), density (BMD), and trabecular thickness (Tb.Th) progressively increased in the alveolar socket, which gradually decreased in Tb.Sp and Tb.N. LH showed no significant change during the same period. Osteogenic marker OCN and OPN increased during bone repair from two to eight weeks. The reduced height of the lingual wall of the tooth extraction socket was rarely repaired in the later repair stage. Osteoclast activity led to absorption of the alveolar ridge of the alveolar bone wall within two weeks after operation. We observed positive expression of EMMPRIN and MMP-9 in osteoclasts that participated in the absorption of the spire region.
Extraction of rat mandibular second molars may help the study of alveolar ridge absorption and preservation. The EMMPRIN-MMP-9 pathway may be a candidate for further study on attenuating bone resorption after tooth extraction.
颊舌侧牙槽嵴宽度明显不同的大鼠下颌第二磨牙拔牙窝的特征仍不清楚。
观察大鼠下颌第二磨牙拔除后牙槽嵴的变化，并在牙槽嵴吸收和保存的实验模型中观察牙槽窝愈合过程。
纳入 18 只 Wistar 大鼠，根据研究中的愈合时间分为 6 组。双侧下颌第二磨牙被拔除。拔牙窝的大鼠接受 0、1.5、2、3、4 和 8 周的愈合。进行组织学观察、抗酒石酸酸性磷酸酶（TRAP）染色、Masson 三色染色、免疫组织化学染色和微计算机断层扫描（micro-CT），以评估牙槽嵴的变化。
不同的颊舌侧牙槽嵴宽度导致不同的高度损失。拔牙后两周，舌侧壁高度（LH）显著下降。颊侧壁高度很少减少其较高的牙槽嵴宽度。拔牙后 2 至 8 周，牙槽窝内骨体积（BV/TV）、密度（BMD）和小梁厚度（Tb.Th）逐渐增加，而 Tb.Sp 和 Tb.N 逐渐减少。同一时期 LH 无明显变化。成骨标志物 OCN 和 OPN 在 2 至 8 周的骨修复过程中增加。拔牙窝舌侧壁的降低高度在后期修复阶段很少得到修复。破骨细胞活性导致术后两周内牙槽骨壁的牙槽嵴吸收。我们观察到参与嵴顶吸收的破骨细胞中 EMMPRIN 和 MMP-9 的阳性表达。
大鼠下颌第二磨牙拔除术有助于牙槽嵴吸收和保存的研究。EMMPRIN-MMP-9 通路可能是进一步研究拔牙后骨吸收抑制的候选途径。
