Effect of longstanding jiggling on experimental marginal periodontitis in the beagle dog

The aim of the present experiment was to study the effect of a prolonged period of jiggling force application on the rate of progression of ligature-induced, plaque-associated marginal periodontitis in the beagle dog. The experiment was performed on eight dogs fed a diet which permitted dental plaque accumulation. On Day 0 a phase of periodontal tissue breakdown was initiated around the mandibular fourth premolars (4P; P4) by the placing of plaque retention ligatures around the neck of the teeth. The ligatures were exchanged once a month throughout the entire study. On Day 60 trauma from occlusion of the jiggling type was produced in the P4 region and maintained for 300 days. The animals were sacrificed on Day 360. Following sacrifice tissue sections comprising 1M, 4P, 3P and P3, P4, M1 were produced and subjected to microscopic analysis. The experiment revealed that in the dog jiggling forces applied to teeth which ae also subjected to ligature-induced and plaque-associated marginal periodontitis, may enhance the rate of destruction of the periodontium.     

Influence of trauma from occlusion on progression of experimental periodontitis in the beagle dog

Abstract The experiments were performed in six beagle dogs fed a soft diet which allowed dental plaque formation. During a pre-experimental period of 7 weeks, periodontitis was induced by (1) surgically creating a bony pocket and (2) adapting a copper band to the exposed tooth surface. Two dogs were sacrificed at the end of this period and tissue sections were prepared for histological examination. In the remaining four dogs, trauma from occlusion was produced on the left mandibular fourth premolar by the installation of a cap splint and a bar device. The contralateral premolar served as a control. At the start of, and at regular intervals during, an experimental period of 180 days, tooth mobility, gingival inflammation and plaque accumulation were assessed. After sacrifice, radiographs were taken of test and control tooth regions and histological sections analysed regarding the width of the marginal periodontal ligament space and the degree of apical downgrowth of the gingival pocket epithelium. Only the test teeth showed a gradually increasing horizontal mobility, but gingival inflammation and Plaque Index scores were similar on test and control sides. Radiographs revealed (1) horizontal bone loss in both test and control areas, and (2) angular bone destruction only in test areas. Histological sections showed that the degree of apical proliferation of the pocket epithelium was more pronounced in test than in control regions.     

大鼠实验性牙周炎对胰岛的影响

目的:通过观测实验性牙周炎大鼠胰岛组织形态、检测外周血胰岛素水平和胰岛环氧化酶(cyclooxygenase,COX-2)表达情况,探讨慢性牙周炎对胰岛的影响。方法:将25只SD大鼠随机分为对照组10只和慢性牙周炎组15只,慢性牙周炎组行双侧上颌磨牙结扎法建立牙周炎模型。基线和12周采集外周血,12周处死大鼠,取颌骨和胰腺组织标本做切片,观察牙周和胰腺的组织学改变,测量牙槽骨吸收高度,并采用免疫组织化学法检测胰岛COX-2表达情况。结果:12周时牙周炎组外周血中肿瘤坏死因子(tumor necrosis factor-α,TNF-α)达(10.02±2.16)pg/mL,较对照组(7.64±1.59)pg/mL有明显升高(P<0.05)。但牙周炎组的血清胰岛素水平、胰岛形态和COX-2的表达水平均未见明显差异。结论:中等程度慢性牙周炎尚不足以造成大鼠胰岛组织形态和功能的改变。     

The effect of secondary hyperparathyroidism and hemodialysis therapy on alveolar bone and periodontium

BACKGROUND: Alveolar bone is particularly sensitive to increased levels of parathyroid hormone (PTH) from either primary or secondary hyperparathyroidism (HPT). The purpose of this study was to examine the effect of secondary HPT on the periodontium of patients on hemodialysis. METHODS: The experimental group consisted of 35 patients with secondary HPT, with chronic renal failure treated by hemodialysis (E group). A control group (C group) was formed from 35 healthy age- and gender-matched subjects attending the maxillofacial outpatient clinic for a variety of reasons. Blood samples were taken from the E group, and the biologically active intact parathormone molecule, PTH(1-84), was assayed using two-site immunoradiometric assay (IRMA). The time of onset and the duration since diagnosis of HPT was also recorded. In addition, for a subgroup of 25 matched pairs of patients, a clinical periodontal examination was performed, and the Ramfjord index teeth were recorded for: Plaque index (PI); Gingival index (GI); Probing depth (PD); and Clinical attachment level (CAL). A standardized panoramic X-ray was taken from all patients and computer-based linear measurements were used to assess alveolar bone loss (BL). Unpaired Student's t-test served to compare the two groups. Pearson's correlation coefficient test was used to study the association between PI, PTH level, disease duration and BL. RESULTS: Demographically, both groups were similar with no statistical difference. PI was also similar in the C and E group (2.03 +/- 0.13 and 1.76 +/- 0.17, respectively). GI, however, was slightly greater in the C group (1.28 +/- 0.09) compared to the E group (0.97 +/- 0.01). PD in the E group (2.92 +/- 0.14 mm) was almost identical to that of the C group (2.90 +/- 0.12 mm). Likewise, CAL in the E group (4.43 +/- 0.29 mm) did not differ from CAL in the C group (4.03 +/- 0.25 mm). Mean BL was also similar in the E and C groups (3.60 +/- 0.23 mm and 3.85 +/- 0.24 mm, respectively). PI showed a positive, significant correlation with BL (r = 0.457, P = 0.0008). CONCLUSION: From this study it can be concluded that secondary HPT does not have an appreciable effect on periodontal indices and radiographic bone height.     

实验性牙周炎动物模型的研究进展

牙周炎动物模型在牙周病病因学、病理学以及防治方面的研究中起着十分重要的作用。本文从实验性牙周炎动物模型建立的机制、方法、实验动物的选择等方面,综述了实验性牙周炎动物模型的研究进展,以期为牙周炎的深入研究提供参考。     

慢性不可预知性应激对大鼠实验性牙周炎预后的影响

目的:探讨慢性不可预知性复合心理应激对大鼠实验性牙周炎模型牙周组织愈合的影响。方法:雄性SD大鼠128只,随机抽取32只作为正常对照组。其余96只大鼠用丝线结扎右上颌第二磨牙颈部,4周后,采用龈沟出血指数和牙周探诊深度验证牙周炎模型。同时将大鼠结扎丝线去除,随机分为牙周炎对照组、牙周炎+应激组、牙周炎+应激+应激对抗药物组,每组32只。实验第5周起,应激组和药物组大鼠每日给予慢性不可预知性应激,同时药物组每日按5 mg/kg腹腔注射氟西汀。于实验第4、5、6、8周进行大鼠体质量测量、行为学测试、血清学检测;采用组织学观察牙周组织炎症反应、牙槽骨丧失、附着丧失以及破骨细胞计数。结果:心理应激大鼠出现体质量增长减慢、行为异常、血清皮质酮与促肾上腺皮质激素浓度升高(P<0.05),心理应激影响下大鼠牙周炎的愈合进程减慢,炎细胞浸润面积、牙槽骨吸收量与破骨细胞计数在实验第6周和8周、附着丧失在第8周高于对照组(P<0.05)。抗应激药物可逆转心理应激对牙周炎愈合过程的影响,该组炎细胞浸润面积与牙槽骨吸收在第6周和8周、破骨细胞计数在第8周明显低于应激组(P<0.05)。结论:慢性不可预知性心理应激能影响牙周组织的愈合,影响牙周炎的预后。而药物对抗应激能够减轻这种影响。     

The effect of progressive tooth mobility on destructive periodontitis in the dog

Abstract. The aim of the present study was to assess the influence of traumatic forces causing a gradually increasing tooth mobility on an ongoing destructive periodontitis.
The experiments were performed in five dogs fed a diet which permitted dental plaque accumulation. Periodontal breakdown was induced around the mandibular third and fourth premolars (₄P, ₃P and P₃, P₄) by the placement of plaque retention ligatures around the neck of the teeth. After 330 days, when approximally 50 % of the supporting tissues had been lost, mucoperiosteal flaps were raised around the four premolars and notches prepared in the buccal root surfaces at the marginal termination of the alveolar bone. The notches served as landmarks for measurements to be made in histological sections. The flaps were resutured and new plaque retention ligatures placed around the roots of all four teeth.
One week later (Day 0), P₃ and P₄ (test teeth) were subjected to jiggling forces in a bucco-lingual direction with the use of an elevator. The jiggling procedure which had a duration of 30 seconds, was repeated on Days 4, 8, 12 and 16, and was guided in such a way that the tooth mobility gradually increased during the experimental period. The animals were sacrificed on Day 26, and sections of ₄P,₃P and P₃, P₄ were prepared for light microscopic examination.
The results of the study demonstrated that jiggling forces, resulting in a progressive increase of tooth mobility, mediated an enhanced rate of destruction of the supporting apparatus in dogs with an ongoing process of periodontal tissue breakdown.     

Effect of dietary omega-3 polyunsaturated fatty acids on experimental periodontitis in the mouse

Background and Objective:  Periodontitis is an infective disease caused predominantly by gram-negative anerobes. The host inflammatory response to these bacteria causes alveolar bone loss, which characterizes periodontitis. Omega-3 polyunsaturated fatty acids have recognized anti-inflammatory effects; their oxygenated derivatives are key mediators in reducing inflammation. In this study we tested the hypothesis that dietary supplementation with tuna fish oil rich in the n-3 polyunsaturated fatty acid, docosahexaenoic acid, would reduce alveolar bone loss in mice inoculated with periodontopathic bacteria.
Material and Methods:  Adult mice were fed experimental diets containing either 10% tuna oil or Sunola oil for 57 d. After 14 d, 35 mice on each diet were inoculated orally with Porphyromonas gingivalis , with a mixture of P. gingivalis and Fusobacterium nucleatum , with carboxymethylcellulose or remained untreated. The mice were killed, and soft tissue biopsies from the oral cavity of treated mice were used to determine the polyunsaturated fatty acid concentrations. The maxilla was removed, stained and digitally imaged to assess bone loss around the upper molars.
Results:  n-3 polyunsaturated fatty acid levels were significantly higher in oral soft tissues of mice fed tuna oil compared with the control group. Mice fed tuna oil and inoculated with P. gingivalis or with the combination of F. nucleatum and P. gingivalis exhibited 72% and 54% less alveolar bone loss respectively, compared with the treatment control group.
Conclusion:  Alveolar bone loss was inversely related to n-3 polyunsaturated fatty acid tissue levels. In conclusion, fish oil dietary supplementation may have potential benefits as a host modulatory agent in the prevention and/or adjunctive management of periodontitis.     

一氧化碳释放分子对大鼠实验性牙周炎的影响

目的 研究一氧化碳释放分子（CORM）对大鼠实验性牙周炎的影响。方法 将42只健康雄性Wistar大鼠分为正常组（ NL组）、牙周炎组（ LO组）和一氧化碳干预组（ CO组）。NL组不作任何处理;CO及LO组采用牙周丝线结扎法建立牙周炎实验模型;建模当天起 CO组经腹腔注射 CORM-2,每天 10 mg•kg-1,连续 10 d,LO组注射等体积生理盐水。分别于结扎 3、7、10 d后自心脏抽取静脉血,用酶联免疫吸附测定法检测血清中肿瘤坏死因子 -α（TNF-α）和白细胞介素 -1β（IL-1β）的质量浓度。10 d后在体视显微镜下测量牙槽骨的吸收高度,并于光镜下观察牙周组织炎症细胞的浸润情况。结果 丝线结扎10 d后,LO、CO组牙槽骨的吸收高度均明显大于NL组,而CO组明显小于 LO组（ P<0.05）; LO、CO组炎症细胞浸润指数明显高于 NL组,而 CO组明显低于 LO组（ P<0.05）。在同一观察时期内, LO组TNF-α及IL-1β质量浓度均明显高于其他两组,而 CO组虽高于 NL组,但明显低于 LO组（ P<0.05）。结论 CORM-2能有效抑制大鼠实验性牙周炎的炎症细胞浸润和牙槽骨吸收。     

The effect of spironolactone on experimental periodontitis in rats

BACKGROUND: Elevated levels of tumour necrosis factor (TNF) have been found in patients with adult periodontitis. Animal studies have shown that TNF plays an important role in the pathogenesis of periodontitis. New findings suggest that the aldosterone-inhibitor spironolactone possesses an anti-TNF effect. The purpose of the study was to determine the anti-TNF effect of spironolactone in an endotoxic shock rat model and to disclose the effect of oral administration of spironolactone on the development of experimental periodontitis in rats. METHODS: The study was divided in two parts. Part 1: oral administration of spironolactone (100 mg/kg) followed by intravenous lipopolysaccharide (1 mg/kg) infusion 45 min later. Blood samples were taken before and 90 min after lipopolysaccharide infusion to determine the TNF levels in spironolactone treated and non-treated rats. Part 2: oral administration of spironolactone [100 mg/(kg day)] starting 2 days prior to induction of experimental periodontitis established by peridental ligatures. Morphometrical and radiographical registrations of alveolar bone destruction were carried out to determine the effect of spironolactone on the progression of experimental periodontitis. RESULTS: In part 1 the endotoxic shock model showed a significant reduction in TNF levels in the spironolactone-treated group compared to the non-treated group, suggesting that spironolactone acts as a TNF inhibitor. In part 2 spironolactone-treated rats did not demonstrate significantly less alveolar bone destruction compared to non-treated rats. CONCLUSIONS: The insignificant effect of spironolactone treatment could be explained by the fast metabolism of spironolactone and that spironolactone does not completely inhibit TNF production in rats. Moreover, many other cytokines and mediators involved in alveolar bone destruction may account for the lacking response to spironolactone.     

The effect of topical metronidazole therapy on experimentally-induced periodontitis in the beagle dog

Abstract. The present study was performed to assess the effect of topical metronidazole therapy on ligature-induced periodontitis in beagle dogs. 6 beagle dogs with experimentally-induced periodontitis on the mandibular 2nd, 3rd and 4th premolars were treated with metronidazole 10% dental paste 2 × daily for 4 weeks in an open placebo-controlled study using a split-mouth design. Recordings of probing pocket depth, bleeding on probing and gingival index were performed before commencement of treatment and repeated weekly during the 4-weeks treatment period. Concurrently, samples for microbiological analysis were collected from 2 of the dogs. The results demonstrated that probing pocket depth, bleeding on probing and gingival index had improved significantly in the metronidazoletreated side compared with the placebo-treated side. Black pigmented Bacteroides spp. and Spirochetes, present in all samples before treatment, were eliminated from the metronidazole-treated side after the 1st week of treatment and throughout the treatment period, whereas they were present in all samples from the placebo-treated side. The result of the present study demonstrates that topical application of metronidazole in a dental paste, improves the clinical features of the experimentally-induced periodontitis and eliminates some of the micro-organisms associated with the disease.     

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目的观察局部注射人白细胞介素-10(hIL-10)质粒对去卵巢大鼠实验性牙周炎牙槽骨吸收的影响及其机制。方法本研究于2009年1月至2011年3月在福建医科大学口腔医学院完成。将24只3月龄雌性SD大鼠随机分成4组,分别为假手术+hIL-10(SHAM+hIL-10)组、假手术+空载体(SHAM+VECTOR)组、去卵巢+hIL-10(OVX+hIL-10)组和去卵巢+空载体(OVX+VECTOR)组,每组6只。前两组大鼠实施卵巢切除假手术后12周,丝线结扎左侧上颌第二磨牙,制造实验性牙周炎模型(即形成SHAM+hIL-10+EP和SHAM+VECTOR+EP亚组),右侧不结扎作为对照牙(即形成SHAM+hIL-10+C和SHAM+VECTOR+C亚组)。后两组大鼠实施切除双侧卵巢手术后12周,丝线结扎左侧上颌第二磨牙,制造实验性牙周炎模型(即形成OVX+hIL-10+EP和OVX+VECTOR+EP亚组)。同时,在SHAM+hIL-10组大鼠的双侧上颌第二磨牙腭侧牙龈黏膜下和OVX+hIL-10组大鼠左侧上颌第二磨牙腭侧牙龈黏膜下注射hIL-10质粒(5μg)-脂质体(5μL)复合物;在SHAM+VECTOR组大鼠的双侧上颌第二磨牙腭侧牙龈黏膜下和OVX+VECTOR组大鼠的左侧上颌第二磨牙腭侧牙龈黏膜下注射空载体质粒(5μg)-脂质体(5μL)复合物。隔天注射1次,第7次注射后的48h,处死大鼠。观察各组大鼠骨密度、血清生化指标、牙槽骨吸收和牙周组织细胞因子的变化。结果转染hIL-10质粒后,SHAM+hIL-10+C组、SHAM+hIL-10+EP组和OVX+hIL-10+EP组根分叉区牙周膜IL-10阳性细胞数目分别显著高于SHAM+VECTOR+C组、SHAM+VECTOR+EP组和OVX+VECTOR+EP组(均P<0.05)。同SHAM+VECTOR+C组比较,SHAM+hIL-10+C组牙周膜IL-1β阳性细胞数目显著减少(P<0.05),RANKL阳性细胞数目显著增加(P<0.05)。同SHAM+VECTOR+EP组比较,SHAM+hIL-10+EP组牙周膜的IL-1β、IL-6、TNF-α和RANKL阳性细胞数目均显著减少(P<0.05)。同OVX+VECTOR+EP组比较,OVX+hIL-10+EP组牙周膜的IL-1β、IL-6、RANKL和MMP-8阳性细胞数目均显著减少(P<0.05)。结论局部注射hIL-10质粒可抑制去卵巢大鼠实验性牙周炎的牙槽骨吸收,可能与牙周组织促炎因子的表达下降有关。     

Effects of hippocampal lesioning on experimental periodontitis in Wistar rats

The hippocampus, which is a brain structure involved in learning and memory processes, plays a key role in the feedback regulation of the hypothalamic-pituitary-adrenal (HPA) axis and autonomic sympathetic nervous system, and the subsequent secretion of immuno-modulatory hormones in response to pathogenic microorganisms. Dysregulation of these brain-neuroendocrine-immune regulatory networks, which act in concert to maintain homeostasis, is found to be of critical importance to the host defence against pathogens, as well as susceptibility to diseases, including periodontal disease. The present study was designed to determine the effects of hippocampal lesioning on the progression of periodontitis. Experimental ligature-induced periodontitis was induced in 16 Wistar rats, which were bilaterally lesioned in their hippocampal region with an aspiration technique that is well documented to impair learning and memory, as well as in 15 sham-operated control rats. The disease progression was evaluated radiographically and histometrically. The results revealed that the hippocampal lesioned rats developed significantly more destruction of the periodontium than did the sham-operated controls. This finding supports recent studies that indicate that inappropriate brain-neuroendocrine regulation of inflammatory responses to infectious agents may play an important role in disease susceptibility and progression.     

Ameliorative effect of quercetin on the destruction caused by experimental periodontitis in rats

Cheng W‐C, Huang R‐Y, Chiang C‐Y, Chen J‐K, Liu C‐H, Chu C‐L, Fu E. Ameliorative effect of quercetin on the destruction caused by experimental periodontitis in rats. J Periodont Res 2010; 45: 788–795. © 2010 John Wiley & Sons A/S Background and Objective: The purpose of this study was to evaluate the effect of quercetin, a flavonol that exhibits anti‐inflammatory properties, on experimental periodontal destruction in rats. Material and Methods: Osteoclast formation on maxillary palatal alveolus was induced with daily lipopolysaccharide (LPS) injections (0, 1 or 5 mg/mL) for 3 d. Five days later, the osteoclasts on bony surfaces were counted after histochemical staining for tartrate‐resistant acid phosphatase. The effect of intragastric quercetin on the osteoclast formation was evaluated in the following three groups: quercetin (75 mg/kg/d by oral feeding); LPS (5 mg/mL); and quercetin plus LPS. Moreover, the effect of quercetin on the ligature‐induced periodontitis around maxillary second and mandibular first molars was further evaluated by microcomputerized tomography (on days 0, 4, 8 and 12) and by histometry (on day 8). Results: A dose‐dependent increase in osteoclasts occurred after LPS injections. However, quercetin (75 mg/kg) reduced the 5 mg/mL LPS‐induced osteoclasts. Using microcomputerized tomography, the bone crest levels at ligation sites were found to be significantly more apical than at the control sites on days 8 and 12; however, the apically located bone crests rebounded in rats from the quercetin‐plus‐ligation group. Histometry demonstrated significantly more coronal alveolar crest bone levels, less inflammatory cell‐infiltrated connective tissue areas and less connective tissue attachments in the ligation‐plus‐quercetin group compared with those in the ligation group. Conclusion: As the quercetin could reduce the LPS‐induced osteoclast formation and the ligature‐enhanced periodontal inflammation and bone loss, we suggest that it may have an ameliorative effect on periodontal destruction.     

实验性糖尿病牙周炎诱导成骨细胞凋亡的研究

目的观察糖尿病牙周炎条件下成骨细胞的凋亡情况。方法选用SD大鼠62只,随机分为糖尿病牙周炎组（DP）、单纯牙周炎组（P）以及空白对照组（N）。采用一次性腹腔注射链脲佐菌素（STZ）的方法诱导大鼠糖尿病模型,采用丝线结扎联合口内接种细菌的方法建立牙周炎模型。各组动物分别于DP组、P组丝线结扎后第3、6周时分批处死,取标本进行组织学检测,并计算各组成骨细胞凋亡百分率。结果丝线结扎后3、6周时,成骨细胞凋亡百分率由高至低依次为DP组、P组、N组,组间两两比较均有统计学意义（P＜0.05）。在丝线结扎后3周和6周时,DP组成骨细胞凋亡百分率均达到P组的2倍。结论糖尿病可促进牙周炎条件下牙周组织中成骨细胞的凋亡。