Pulp revascularization in reimplanted immature monkey incisors – predictability and the effect of antibiotic systemic prophylaxis

Abstract In 32 monkeys 105 immature maxillary incisors were extracted and reimplanted either immediately or after 30 or 60 min wet or dry storage. Of the monkeys, 17 (group I) did not receive and 15 (group II) received prophylactic treatment with 4 mg/kg doxycycline before extraction and 2 mg/kg for 5 d after reimplantation. The observation time varied from 6 to 8 weeks. After being histologically processed, the material was evaluated with respect to the amount of vital tissue and presence of microorganisms in the pulpal lumen. A comparison revealed no difference in the results between the groups. The results were therefore pooled and statistically analysed with respect to the significance of apical foramen width, extra-alveolar time, wet or dry storage and presence of micro-organisms in the pulpal lumen for the occurrence of complete pulp revascularization (CPR). The overall frequency of CPR was 18%. Log-linear analyses (SAS, 1985) of the material as a whole or of separate parameters consistently revealed a relationship between presence of microorganisms and absence of CPR (P= 0.0001). A higher frequency of CPR and a lower frequency of micro-organisms (P= 0.05) was found only for the group of immediately reimplanted teeth. The presence of micro-organisms could be explained for 61 teeth. In 27 of these, blood clots containing bacteria in the apical portion of pulpal lumen indicated contamination during the extra-alveolar time, while in 34, the micro-organisms originated from plaque covered mechanical damage in the cervical part of the root surface.     

Pulp revascularization in reimplanted immature monkey incisors--predictability and the effect of antibiotic systemic prophylaxis.

In 32 monkeys 105 immature maxillary incisors were extracted and reimplanted either immediately or after 30 or 60 min wet or dry storage. Of the monkeys, 17 (group I) did not receive and 15 (group II) received prophylactic treatment with 4 mg/kg doxycycline before extraction and 2 mg/kg for 5 d after reimplantation. The observation time varied from 6 to 8 weeks. After being histologically processed, the material was evaluated with respect to the amount of vital tissue and presence of micro-organisms in the pulpal lumen. A comparison revealed no difference in the results between the groups. The results were therefore pooled and statistically analysed with respect to the significance of apical foramen width, extra-alveolar time, wet or dry storage and presence of micro-organisms in the pulpal lumen for the occurrence of complete pulp revascularization (CPR). The overall frequency of CPR was 18%. Log-linear analyses (SAS, 1985) of the material as a whole or of separate parameters consistently revealed a relationship between presence of micro-organisms and absence of CPR (P = 0.0001). A higher frequency of CPR and a lower frequency of micro-organisms (P = 0.05) was found only for the group of immediately reimplanted teeth. The presence of micro-organisms could be explained for 61 teeth. In 27 of these, blood clots containing bacteria in the apical portion of pulpal lumen indicated contamination during the extra-alveolar time, while in 34, the micro-organisms originated from plaque covered mechanical damage in the cervical part of the root surface.     

牙髓血运重建术用于根尖孔宽大的年轻恒牙临床疗效分析

目的:通过对根尖孔未发育完全的年轻恒牙实施牙髓血运重建治疗,并追踪随访患牙9~24个月,观察牙髓血运重建术的临床疗效。方法:对9例(11颗牙)患牙进行常规开髓,清除坏死的牙髓组织,2.5%的次氯酸钠和17%的EDTA溶液冲洗后封入三联抗生素糊剂。待患牙临床症状消失后,对其进行牙髓血运重建术,严密冠方封闭,定期复诊观察。结果:9例(11颗牙)年轻恒牙经牙髓血运重建术治疗后,临床症状全部消失。其中,6颗牙根尖孔闭合,牙根发育,牙髓电活力测试有反应;4颗牙根尖孔闭合,牙根发育,牙髓电活力测试无反应;1颗牙治疗失败。结论:牙髓血运重建术能使牙根继续发育,为治疗牙髓炎症、坏死和根尖周感染的年轻恒牙提供了可选择的方法。     

Replantation of 400 avulsed permanent incisors. 2. Factors related to pulpal healing

Abstract Four hundred avulsed and replanted permanent teeth were examined for pulpal healing. In 110 teeth, the apical foramen was either open or half-open. In 16 teeth, the pulps were extirpated prophylactically. Thus, pulpal revascularization was considered possible in 94 teeth. Revascularization occurred in 32 teeth (34%). Pulp necrosis could usually be demonstrated after 3 weeks. Positive pulpal sensibility and radiographis signs of pulp canal obliteration were usually observed after 6 months. The effect of various clinical factors was examined, such as sex, age, type of tooth replanted, stage of root formation, type and length of extra-alveolar storage, clinical contamination of the root surface, type of cleansing procedure of the root surface, type and length of splinting and the use of antibiotics. Finally, the width of the apical foramen and the length of the root canal were measured on radiographs taken at the time of injury. A multivariate statistical analysis revealed that pulpal revascularization was more frequent in teeth with shorter distances from the apical foramen to the pulp horns. Furthermore, that wet storage (saliva and/or saline) for more than 5 min decreased the chance of pulpal revascularization; whereas dry extraalveolar storage had a monotonous effect on pulpal revascularization, i. e. decreasing chance of revascularization with increasing length of the extraalveolar dry storage. Based on these findings, immediate replantation after brief cleansing in either tap water or saline is recommended.     

Effect of topical application of doxycycline on pulp revascularization and periodontal healing in reimplanted monkey incisors.

Maxillary incisors in 47 monkeys, 54 in the experimental group (I) and 117 in the control group (II), were extracted and reimplanted, either immediately or after 30 or 60 min wet or dry storage. Incisors in the experimental group I were additionally kept 5 min in a suspension of 1 mg doxycycline in 20 ml physiologic saline, freshly prepared for each of the 15 animals before reimplantation. The observation time varied from 6 to 8 weeks. The teeth were removed in tissue blocks, histologically processed and evaluated for occurrence of complete pulp revascularization (CPR), presence of the micro-organisms in the pulpal lumen and ankylosis or inflammatory root resorption. Then the results were statistically evaluated, using log-linear analyses and chi-square tests (SAS, 1985) for the comparisons between group I and group II. These analyses revealed that topical application of doxycycline increased the frequency of complete pulp revascularization (P less than 0.002) and decreased the frequency of micro-organisms in the pulpal lumen (P less than 0.001). Furthermore, the frequencies of ankylosis (P less than 0.05) and inflammatory root resorption (P less than 0.001) were also decreased compared with the control group of teeth. It was concluded that the effect of topical treatment with doxycycline was most probably exerted on the micro-organisms that contaminated root surface during the extra-alveolar time; contamination of necrotic pulp tissue from the mechanical damage in the cervical part of the root surface was not affected.     

Effect of topical application of doxycycline on pulp revascularization and periodontal healing in reimplanted monkey incisors

Abstract Maxillary incisors in 47 monkeys, 54 in the experimental group (I) and 117 in the control group (II), were extracted and reimplanted, either immediately or after 30 or 60 min wet or dry storage. Incisors in the experimental group I were additionally kept 5 min in a suspension of 1 mg doxycycline in 20 ml physiologic saline, freshly prepared for each of the 15 animals before reimplantation. The observation time varied from 6 to 8 weeks. The teeth were removed in tissue blocks, histologically processed and evaluated for occurrence of complete pulp revascularization (CPR), presence of the micro-organisms in the pulpal lumen and ankylosis or inflammatory root resorption. Then the results were statistically evaluated, using log-linear analyses and chi-square tests (SAS, 1985) for the comparisons between group I and group II. These analyses revealed that topical application of doxycycline increased the frequency of complete pulp revascularization (P < 0.002) and decreased the frequency of micro-organisms in the pulpal lumen (P < 0.001). Furthermore, the frequencies of ankylosis (P < 0.05) and inflammatory root resorption (P < 0.001) were also decreased compared with the control group of teeth. It was concluded that the effect of topical treatment with doxycycline was most probably exerted on the micro-organisms that contaminated root surface during the extra-alveolar time; contamination of necrotic pulp tissue from the mechanical damage in the cervical part of the root surface was not affected.     

牙髓血运重建术治疗年轻恒牙牙髓坏死伴根尖周病变临床疗效及锥形束CT影像定量评价

目的　探讨运用牙髓血运重建术治疗年轻恒牙牙髓坏死伴根尖周病变的临床疗效并进行影像学定量评价。方法    选择2018年1—11月于上海市口腔医院牙体牙髓病科就诊的18例年轻恒牙牙髓坏死伴根尖周病变患者的18颗患牙（均为单根管的下颌前磨牙）,行牙髓血运重建术。术后随访18个月,期间收集临床及影像学数据,分析临床疗效并对牙根影像面积、根尖孔直径以及牙根长度变化进行CBCT影像定量评估,分析可能影响术后牙根发育的因素。结果　所有18颗经过治疗的患牙临床症状均消失,无叩痛、松动及窦道,有效率为100%,其中成功15例（83.3%）、好转3例（16.7%）。以术前为基准,术后18个月牙根影像面积平均增加83.78%,根尖孔直径平均减少50.78%,牙根长度平均增加24.61%;年龄（是否大于17岁）与牙根是否继续发育相关,性别及根尖孔大小与牙根是否继续发育无明显相关性。结论    对于牙髓坏死伴根尖周病变的年轻恒牙,采用牙髓血运重建术可使牙根得到持续发育,年龄可影响术后牙根发育水平。     

牙髓血运重建治疗年轻恒牙根尖周病变的临床观察

目的 观察年轻恒牙进行牙髓血运重建术后牙根发育及根尖周病变愈合情况.方法 选取慢性根尖周炎或慢性根尖周炎急性发作的单根管年轻恒牙16例,要求牙根发育Nolla分期7～9期.行牙髓血运重建术治疗,随访观察2年,定期进行临床检查并拍摄X线片观察牙根发育及根尖周病变的愈合情况.结果 16例单根管年轻恒牙牙髓血运重建术后12例牙根继续发育.其中13例在定期复查时牙髓电活力测试结果表现为阳性;16例术后根尖周病变均完全愈合,愈合时间因病变大小而不同,平均愈合时间为4.1个月.疗效评价为成功12例,好转4例,失败0例.结论 牙髓血运重建术治疗年轻恒牙根尖周病变,取得良好的治疗效果.     

Relationship between pulp dimensions and development of pulp necrosis after luxation injuries in the permanent dentition

Abstract A relationship between type of luxation injury, stage of root development and development of pulp necrosis after injury has been demonstrated. It was therefore decided to delve more deeply into the relationship between stage of root development and the later development of pulp necrosis after injury in a material of luxated permanent teeth. In this context, the diameter of the apical foramen and the distance from the apical foramen to the pulp horn, as measured on radiographs taken at the time of injury, were used as indicators of root development. In order to justify this approach, the precision of the measuring technique and the accuracy of the radiographic technique were studied. Regarding precision of the measuring technique, it was found that there was a 1% to 4.3% error of the means of all measurements for the various parameters and exposure techniques employed. With respect to accuracy of the radiographic technique, it was found that there was a systematic error in the radio-graphic technique which resulted in a median relative distortion of between 3.5% and 8% image magnification for the various parameters and the exposure techniques employed. These findings indicated that the measuring technique employed in the present investigation was reliable for studying the parameters in question. In a material of 226 extruded, intruded and laterally luxated maxillary permanent incisors, observed for up to 10 years, it was found that the development of pulp necrosis after injury was significantly related to the diameter of the apical foramen. For extruded and laterally luxated teeth, the smaller the diameter, the greater the probability of pulp necrosis. Intruded teeth with incomplete root development (i.e. radiographic diameters ≥1.2 mm) were associated with a much higher probability of pulp survival than teeth with complete root development (i.e. radiographic diameters ≤0.7 mm). The distance from the apical foramen to the pulp horn did not appear to be of importance in predicting pulp survival when diameter of the apical foramen was taken into account. Pulp survival after luxation injuries with displacement thus appears to be dependent upon the size of apical contact between the pulp and the periodontium.     

Revascularization of immature permanent incisors after severe extrusive luxation injury

Pulp necrosis is an uncommon sequel to extrusive luxation in immature teeth with incomplete apical closure. In this report, we describe the management of severely extruded immature maxillary incisors and the outcome of revascularization to treat subsequent pulp necrosis. An 8.5-year-old boy with severe dentoalveolar trauma to the anterior maxillary region as a result of a fall was provided emergency treatment consisting of reduction of the dislodged labial cortical bone and repositioning of the central incisors, which had suffered extrusive luxation. When he presented with spontaneous pain involving the traumatized incisors a week later, the teeth were treated via a revascularization protocol using sodium hypochlorite irrigation followed by 3 weeks of intracanal calcium hydroxide, then a coronal seal of mineral trioxide aggregate and resin composite. Complete periradicular healing was observed after 3 months, followed by progressive thickening of the root walls and apical closure. Follow-up observations confirmed the efficacy of the regenerative treatment as a viable alternative to conventional apexification in endodontically involved, traumatized immature teeth.     

The effect of extra-alveolar root filling with calcium hydroxide on periodontal healing after replantation of permanent incisors in monkeys

The effect of calcium hydroxide, used as an extra-alveolar root filling material, on periodontal healing was examined in green vervet monkeys (Cercopithecus aethiopa). Incisors were extracted and a root canal filling of calcium hydroxide paste was processed. Control teeth were replanted after either pulp extirpation or root filling with gutta-percha. In the experimental groups, the extra-alveolar period was either 18 or 120 minutes. The animals were killed eight weeks after replantation, and the replanted teeth were examined histologically. The histologic parameters recorded for each tooth were surface resorption, inflammatory resorption, replacement resorption (ankylosis), periapical inflammatory changes, and downgrowth of pocket epithelium. Teeth with canals filled with calcium hydroxide that had an extra-alveolar time period of 18 minutes, showed noticeably more replacement resorption than either the teeth with canals filled with gutta-percha or those with extirpated pulps. Calcium hydroxide paste may diffuse through the apical foramen, thus injuring the periodontal ligament in the apical region. Consequently, the use of calcium hydroxide does not seem justified in the initial treatment of avulsed teeth, but it can be used after some weeks when periodontal ligament healing has progressed.     

Periodontal and pulpal healing of monkey incisors preserved in tissue culture before replantation.

The effect of delayed replantation and tissue culture as a prevention against root resorption was examined in green Vervet monkeys (Cercopithecus aethiops). Extracted incisors were kept in tissue culture medium (Eagle's medium) for 5--14 days before replantation. The extra-alveolar dry period before tissue culture ranged from to 0 to 60 min. Incisors not subjected to tissue culture served as controls. The animals were sacrificed 8 weeks after replantation. The following histologic parameters were registered for each tooth: surface resorption, inflammatory resorption, replacement resorption (ankylosis), downgrowth of pocket epithelium, and periapical inflammatory changes. The evaluation of the pulp included the extent, recorded in mm, of pulp survival. Histometric evaluation showed that teeth immediately placed in tissue culture medium for 5--14 days showed improved periodontal healing, exhibiting significantly less inflammatory resorption than control teeth immediately replanted. Also the extent of pulp survival was significantly increased in teeth replanted after tissue culture. Teeth bench-dried for 60 min and thereafter placed in tissue culture medium also showed a significant reduction in the amount of inflammatory resorption and increased amount of pulp survival compared with control teeth replanted after the 60-min dry extra-alveolar period. Replacement resorption (ankylosis) was found in all teeth in both groups.     

A retrospective clinical and radiologic study of teeth re-implanted following traumatic avulsion

Abstract Re-implantation is the recommended therapeutic procedure following traumatic exarticulation of teeth though its long-term prognosis remains controversial. The purpose of the following study was to evaluate the periodontal healing of 33 reimplanted incisors lost after trauma. The sample, which included 24 upper and 9 lower incisors, was divided in two groups: 15 teeth were reimplanted within 1 hour (=Group A) and 21 teeth after 3 hours or more (=Group B). The reimplanted teeth were followed for different radiographic evaluation periods up to 5 years (mean = 2–9 years). The results showed a high rate of periodontal healing in Group A (66.7%), while Group B demonstrated a high percentage (83.3%) of both inflammatory and replacement resorption. Thus, even if the whole sample was prevented from drying before reimplantation, the teeth were affected by different rates of root resorption. Among the various prognostic factors suggested by the literature, bacterial contamination during extra-alveolar storage seemed the most critical.     

Effect of Residual Dental Pulp Tissue on Regeneration of Dentin-pulp Complex: An In Vivo Investigation

Introduction

Current pulp revascularization procedures in teeth with necrotic pulps and open apices have produced histologic evidence of connective tissue growth, cementum, and bone within the root canals of experimental animals. This study aims to investigate the effect of maintaining uninflamed residual apical pulp tissue on the histologic outcome of pulp-dentin complex regeneration after a revascularization procedure in immature ferret cuspid teeth.

Pulp revascularization for immature replanted teeth: a case report

Immature avulsed teeth are not usually treated with pulp revascularization because of the possibility of complications. However, this therapy has shown success in the treatment of immature teeth with periapical lesions. This report describes the case of an immature replanted tooth that was successfully treated by pulp revascularization. An 8‐year‐old boy suffered avulsion on his maxillary left lateral incisor. The tooth showed incomplete root development and was replanted after 30 minutes. After diagnosis, revascularization therapy was performed by irrigating the root canal and applying a calcium hydroxide paste and 2% chlorhexidine gel for 21 days. In the second session, the intracanal dressing was removed and a blood clot was stimulated up to the cervical third of the root canal. Mineral trioxide aggregate was placed as a cervical barrier at the entrance of the root canal and the crown was restored. During the follow‐up period, periapical repair, apical closure and calcification in the apical 4 mm of the root canal was observed. An avulsed immature tooth replanted after a brief extra‐alveolar period and maintained in a viable storage medium may be treated with revascularization.     

Comparative evaluation of Platelet Rich Plasma (PRP) versus Platelet Rich Fibrin (PRF) scaffolds in regenerative endodontic treatment of immature necrotic permanent maxillary central incisors: A double blinded randomized controlled trial

ObjectivesThe research aims to assess the regenerative potential of Platelet Rich Plasma (PRP) versus Platelet Rich Fibrin (PRF) scaffolds in immature permanent maxillary central incisors with necrotic pulps, clinically and radiographically.Trial designDouble blinded parallel randomized controlled trial was implemented to identify the results.Subject & methodsThe proposed study was conducted among 30 patients with maxillary necrotic permanent immature central incisors but only 26 patients fulfilled the study requirements. Group I was treated with PRP and Group II with PRF scaffolds. Follow up has been done every 3 months for one year. Primary outcomes were measured clinically: Pain, Mobility, Swelling, and Sinus/fistula. Radiographically: increase root length and width. Secondary outcomes were clinically: Discoloration and Sensibility test. Radiographically: increase in bone density measurements and decrease in apical diameter. Standardized radiographs were collected during the follow up period, and radiographic changes were measured by using Image J software. Statistical analysis was performed on 25 patients who had completed the study.ResultsAll 25 patients' teeth were survived during the 12-month follow-up period. PRP showed marginal increase in radiographic root length and width, periapical bone density and a decrease in apical diameter. No statistical significant differences were observed when it was compared with PRF. The teeth which were treated did not respond to sensibility test at the end of the study. PRF displayed statistical significant higher amount of crown discoloration when compared to PRP group.ConclusionsFor necrotic immature teeth, revascularization using PRP is an appropriate alternative to PRF and showed excellent 12-months prognosis.     

Effect of extra-alveolar period and storage media upon periodontal and pulpal healing after replantation of mature permanent incisors in monkeys

The effect of extra-alveolar period and storage media upon periodontal and pulpal healing after replantation was studied in green Vervet monkeys (Cercopithecus aethiops). Mandibular lateral incisors were extracted. The extra-alveolar period before replantation was 0, 18, 30, 60, 90, and 120 min. The storage media for the extracted teeth were tap water, physiologic saline, saliva or dry storage. The animals were sacrificed 8 weeks after replantation and the replanted teeth were examined histometrically. The following histologic parameters were registered for each tooth: surface resorption, inflammatory resorption, replacement resorption (ankylosis), periapical inflammatory changes, the extent of vital pulp and downgrowth of pocket epithelium. A significant relationship was found between the frequency of root resorption, extra-alveolar period and storage medium. This was especially evident after dry storage. Surface resorption was found with approximately the same frequency irrespective of extra-alveolar period and storage media. Inflammatory root resorption was especially common after dry storage and was related to the length of the extra-alveolar period. Already after 30 min dry storage, this resorption type was very prominent. Teeth stored in tap water, saline or saliva showed about the same frequency of inflammatory resorption, which increased slightly with increased extra-alveolar periods. Replacement resorption showed a strong relationship to dry storage and became very prominent after 60 min. Replacement resorption was rarely found among teeth stored in saline or saliva; whereas it was significantly increased among teeth stored in tap water. It is concluded that saline and saliva offer good protection against root resorption during the extra-alveolar period.     

年轻恒前牙感染根管内血管再生的动物实验研究

目的通过建立根尖周炎模型观察年轻恒前牙根管内血管再生的组织学状况。方法选择4个半月龄杂种犬1只,建立上颌未发育完成的恒前牙根尖周炎模型,将6颗上颌恒前牙随机分组,对照组3颗采用根尖诱导成形术,实验组3颗采用根管内血管再生术。将术后1、4、8周的X线片分别与术前X线片进行对比,观察牙根继续发育及根尖炎症的愈合情况。术后8周处死动物,利用苏木精-伊红（HE）染色观察根尖闭合情况及根管内容物的构成。结果X线观察,术后1、4周,2组牙根的根尖孔大小及根尖透射区范围未见明显改变。术后8周,实验组根尖透射区范围缩窄较明显,并出现根尖孔缩窄的趋势,但管壁厚度无明显变化;而对照组根尖透射区变化不一。组织学检查,实验组管腔内可见肉芽组织,其中包含有大量的不规则的类牙本质、类牙骨质和类骨质样钙化物,钙化物以根尖部和管腔内侧壁尤为明显。对照组管腔未见软组织,根尖部有少量的硬组织沉积。结论血管再生术可促使年轻无髓恒前牙的慢性根尖周炎症消退,根管内再生的肉芽组织中有硬组织沉积。     

冠折年轻恒前牙活髓切断术后临床及X线研究

目的观察冠折年轻恒前牙活髓切断术后的X线表现并进行测量，为行活髓切断术治疗的牙齿在牙根形成后是否需要及时改做根管治疗提供依据。方法回顾分析25例（31颗牙）曾行活髓切断术、牙根已形成的冠折年轻恒前牙的病例资料，并对其中的12例仅单侧上中切牙冠折病例（对侧上中切牙正常，无外伤史）和50名志愿者的100颗正常上中切牙分别进行了X线片的测量。结果活髓切断术后牙根继续发育，根长及根尖形态均与正常牙相似，但部分患牙根管可明显缩窄，甚至几乎根尖闭锁。测量结果显示正常双侧上中切牙距根尖为根长1／4、1／2、3／4处根管径的宽度[右上切牙分别为（0．67±0．14）mm，（1．05±0．19）mm，（1．78±0．34）mm，左上切牙分别为（0．66±0．12）mm，（1．04±0．17）mm，（1．76±0．30）mm]差异无统计学意义（P〉0．05），而活髓切断术后的冠折牙齿与其对侧正常中切牙相比距根尖为根长1／4、1／2、3／4处根管径的宽度明显缩窄[活髓切断中切牙分别为（0．70±0．23）mm，（1．16±0．24）mm，（1．96±0．34）mm，对侧正常中切牙分别为（0．99±0．17）mm，（1．51±0．25）mm，（2．24±0．36）mm]，差异有统计学意义（P〈0．05）。结论活髓切断术后的冠折牙齿其根管有缩窄、钙化趋势，当牙根形成时，尤其是需利用髓腔和根管固位进行修复者，不宜观察时间过长，最终应打通钙化桥进行根管治疗。     

The effect of apicoectomy before replantation on periodontal and pulpal healing in teeth in monkeys

The effect of resection of the apical part of the root before replantation upon periodontal and pulpal healing was studied in 7 green Vervet monkeys (Cercopithecus aethiops) using teeth with incomplete and complete root formation. Maxillary central incisors, mandibular lateral incisors and first and second mandibular molars were used in this experiment. On one side, the tooth was extracted and replanted with an intact root while the contralateral tooth had 2 mm of the apex resected for the purpose of facilitating pulpal repair and eliminating resorption in the resorption-prone region of the root. The replanted teeth were examined histologically 8 weeks after replantation. The histometric analysis revealed no significant difference in periodontal healing between teeth with or without apical resection. With regard to pulpal healing, apical resection was found to lead to significantly less vital pulp tissue in teeth with immature root formation. A similar, but not significant difference was found for mature teeth. Based on these findings, it could not be recommended that apices be resected prior to replantation in order to improve pulpal repair.