The effects of topical application of bisphosphonates on replanted rat molars

Abstract – The purpose of this study was to evaluate the potential usefulness of two bisphosphonates (BPs) (etidronate and zoledronate), compared with that of alendronate, which is a well‐known drug for delayed replantation, in decreasing or preventing inflammatory root resorption and replacement root resorption in replanted teeth. Eighty‐four Sprague Dawley rat maxillary first molars were extracted, dried for 60 min and then replanted after root treatment. The rats were divided into four groups (control, alendronate, etidronate, zoledronate) as following treatments of avulsed root before replantation. At 7, 14, and 28 days postreplantation, the animals were sacrificed and the samples obtained and process for microscopic analysis. The data were statistically analyzed with the SPSS procedure, anova test and each test was complemented by the Tukey’s post hoc test. The result indicated that topical application of alendronate and zoledronate, both nitrogen containing BPs, prevented inflammatory root resorption and inflammatory cell response in the delayed replantation model. Both drugs were demonstrated similar effects in the delayed tooth replantation model (P = 0.9). Etidronate did not prevent inflammatory root resorption and inflammation in the delayed replantation (P < 0.05). No significant differences in replacement root resorption were observed among all drugs. These results suggest that when teeth are dried and not replanted immediately, zoledronate, like alendronate, may prevent root resorption and facilitates the regeneration of periodontal tissues after replantation.     

Factors related to treatment and outcomes of avulsed teeth

Abstract – Background: The aim of this study was to examine factors associated with avulsion injury and to specify the association between these factors and the treatment, as well as the outcomes of avulsed permanent incisors in children. Materials and methods: The sample consisted of 51 children with 62 avulsed permanent incisors, whose injuries had been managed in the period 1998–2006. The study was prospective, recording the history of the accident, concomitant injuries, age, gender, apical maturity of the root, replantation rate, storage media, extra‐alveolar duration, endodontic treatment, compliance and recall appointments response. Factors were analysed in relation to postoperative outcomes, classified as functional healing (FH), infection‐related (inflammatory) resorption (IRR) and replacement resorption (RR). Results: The average age of patients was 10.7 years (range 7–19). In 16/51 patients, tooth avulsion was caused by a road traffic accident. Avulsion was accompanied by concomitant injuries in all cases. Thirty of 62 avulsed teeth were not replanted and 32 incisors were replanted after dry storage. Time until replantation ranged between 15 min and 9 h (median 60 min). The observation period ranged from 1 to 6 years (median 2 years). FH was observed in 5/32, IRR in 20/32 and RR in 7/32 incisors. Ten teeth were extracted during 5‐years of observation. Immature incisors exhibited significantly more complications compared with mature teeth (P = 0.04). Storage media and extra‐alveolar duration did not significantly affect the survival of replanted teeth (P = 0.253, P = 0.350). Teeth in which endodontic treatment was in temporary phase exhibited significantly more complications in comparison with teeth with completed endodontic treatment (P = 0.0l6). Conclusion: The combination of delayed replantation and unphysiological storage is followed by low survival. Incisors with open apices exhibited lower survival compared with incisors with closed apices. Replanted incisors that required prolonged treatment with calcium hydroxide exhibited more complications compared with incisors with completed root canal treatment.     

Histological and immunohistochemical analyses of the chronology of healing process after immediate tooth replantation in incisor rat teeth

Abstract – Dental tissues have special characteristics, and its regenerative capacity is noteworthy. However, understanding the circumstances that lead to regeneration is challenging. In this study, the chronology of the healing process after immediate replantation of rat incisor teeth was examined by histological and immunohistochemical analyses within a 60‐day period. Thirty‐six male Wistar rats had their maxillary right incisors extracted and replanted after 15 min in saline storage. The rats were sacrificed immediately 3, 7, 15, 28, and 60 days after replantation. The histological analysis showed rupture of the periodontal ligament and formation of a blood clot, which started being replaced by a connective tissue after 3 days. At 7 days, the gingival mucosa epithelium was reinserted and areas of root resorption could be seen. At 15 days, the periodontal ligament was repaired. At 3 days, the pulp presented an absence of the odontoblast layer, which started being replaced by a connective tissue. This tissue suffered gradual calcification, filling the root canal at 28 and 60 days. The root ends were closed. The immunohistochemical analysis revealed greater expression of OP, OPG, and RANK proteins in the initial periods (0 and 3 days), while TRAP expression predominated at 28 and 60 days (P < 0.05). In conclusion, in delayed tooth replantation, there is great new bone formation activity in the earlier periods of the repair process, while a predominance of bone resorption and remodeling is observed in the more advanced periods.     

Delayed replantation of rat teeth after use of reconstituted powdered milk as a storage medium

Abstract – Minimal extraoral dry storage period and moist storage for the avulsed tooth are identified as key steps for the treatment protocol of tooth replantation. Among the possible moist storage media, bovine milk has stood out because of its capacity of preserving the integrity of the periodontal ligament (PDL) fibers. This condition has attracted the attention to investigate the use of powdered milk, which is one of the presentation forms of bovine milk, as a feasible storage medium in cases of delayed tooth replantation. The aim of this study was to evaluate the healing process after delayed replantation of rat teeth stored in reconstituted powdered milk and long shelf‐life (ultra high temperature) whole milk. Forty maxillary right rat incisors were assigned to four groups (n = 10): group I – the teeth were extracted and immediately replanted into theirs sockets; group II – the teeth were stored for 60 min in 200 ml of freshly reconstituted powdered milk; group III – the teeth were stored for 60 min in 200 ml of long shelf‐life whole milk; group IV – the teeth were kept dry for the same time. All procedures were performed at room temperature. Next, the root canals of teeth in groups II, III, and IV were instrumented, filled with a calcium hydroxide‐based paste, and replanted into their sockets. All animals received systemic antibiotic therapy and were killed by anesthetic overdose 60 days after replantation. The pieces containing the replanted teeth were removed, fixed, decalcified, and paraffin‐embedded. Semi‐serial 6‐μm‐thick sections were obtained and stained with hematoxylin and eosin for histomorphological analysis. There was statistically significant difference (P < 0.05) between groups I and IV regarding the presence of replacement resorption and PDL remnants on root surface. The powdered milk and long shelf‐life whole milk presented similar results to each other and may be indicated as storage media for avulsed teeth.     

Effect of dexamethasone on root resorption after delayed replantation of rat tooth

The purpose of this study was to evaluate the effect of dexamethasone after delayed tooth replantation with specific regard to root resorption and ankylosis. In addition, the study was planned to elucidate further the usefulness of the model. Fifty-two maxillary first molar teeth were extracted from 26 Sprague-Dawley white female rats fed 0.4% beta-aminoproprionitrile for 3 days to facilitate the extraction. After extraction, the mesiobuccal root canals were endodontically treated under a microscope to prevent subsequent inflammatory resorption of pulpal origin and were assigned to three groups. Teeth in group 1, the dexamethasone group (n = 22), were demineralized in citric acid (1 min), washed, soaked in 1000 nM dexamethasone solution (3 min), air-dried, and replanted in the original sockets. Total extraoral treatment time for each tooth was controlled to 30 min. Teeth in group 2, the dried-only group (n = 22), were air-dried for 30 min after obturation without any surface treatment and replanted. Teeth in group 3, the immediate group (n = 8), were extracted, not root-filled and replanted immediately into their sockets. All experimental animals were killed at 3 weeks after replantation and evaluated histologically. Forty-three of the 52 teeth were available for histological interpretation. They consisted of six immediate, 18 dried-only, and 19 dexamethasone-treated teeth. The degree of progressive root resorption was significantly less in the dexamethasone-treated group than in the dried-only group (p < 0.05). The dexamethasone-treated group exhibited significantly more bone ankylosis than the dried-only group (p < 0.05). These results indicate that the topical use of dexamethasone may be of value in reducing the degree or rate of progressive root resorption secondary to traumatic avulsion and that the rat is a reasonable model for tooth replantation.     

Delayed tooth replantation in rats: effect of systemic antibiotic therapy with amoxicillin and tetracycline

Systemic antibiotic therapy (SAT) has usually been recommended after tooth replantation, but its actual value has been questioned. As there are no reports in the literature about its influence on tooth replantation, the aim of this study was to evaluate the influence of systemic administration of antibiotics (amoxicillin and tetracycline) at the different phases of the repair process (7, 15, 30 days) in delayed rat tooth replantation. Ninety Wistar rats (Rattus norvegicus albinus) had their maxillary right incisors extracted and bench‐dried for 60 min. The dental papilla, enamel organ, pulp tissue, and root surface‐adhered periodontal ligament were removed, and the teeth were replanted. The animals received no antibiotics (n = 30) or were medicated systemically with amoxicillin (n = 30) and tetracycline (n = 30), and were euthanized after 7, 15, and 30 days. Regardless of the evaluation period, the acute inflammatory infiltrate was less intense and root resorption presented smaller extent and depth in the group treated with amoxicillin. The results suggest that SAT has a positive influence on the repair process in delayed tooth replantation and that amoxicillin is an excellent treatment option.     

完全脱位牙即刻与延迟再植根吸收的动态观察

目的：动态观察实验大鼠再植牙牙根吸收及愈合过程,辅助临床治疗及预防再植牙牙根吸收。方法：30只6周龄SPF级Wistar雄性大鼠,分为6组,每组5只,其中一组为空白对照组。实验组大鼠双侧上颌第一磨牙脱位后再植,每只大鼠随机选取一侧脱位牙齿即刻再植,对侧同名牙则于体外干燥保存30min后再植回牙槽窝。分别于术后1、3、7、14、21d处死,分离上颌骨,拍摄x线片,应用IPP软件测量上颌第一磨牙近中根根周透影面积。标本脱钙后制作切片、HE染色,进行组织学观察。结果：再植牙根尖周透影面积随时间延长而增大,干燥组表现尤其明显;组织学上表现为初期炎症反应较明显,随着炎症发展,牙根表面吸收陷窝逐渐增多、增大,后期即刻组牙髓及牙周膜修复反应明显,干燥组牙槽骨修复反应强烈,牙根、牙周膜逐渐被类骨质样组织替代。结论：再植牙初期以炎症反应为主,后期主要表现为修复反应,即刻与延迟再植导致牙周膜细胞活性不同决定了再植牙根吸收的进展。     

全脱出牙延期再植的处理策略

全脱出是牙外伤中最严重的一种类型,及时进行再植非常重要,但临床上常处理的是延期再植的全脱出牙。牙再植的过程包括牙根及牙槽窝的处理、牙齿复位固定、牙髓处理及正确应对牙再植后的并发症。延期再植的牙预后较差,如何通过合适的处理尽量延长再植牙的寿命,是儿童口腔科医生临床工作的难点。文章就全脱出牙延期再植的处理策略做一阐述。     

Immunolocalization of RANK and RANKL along the root surface and in the periodontal membrane of human primary and permanent teeth

Abstract

Objective. Root resorption, impaired tooth eruption and early tooth loss have been described in relation to diseases that involve defects in the RANK-RANKL-OPG-expression. The aim of the present immunhistochemical study was to localize and compare the reactions for RANK and membrane-bound RANKL along root surfaces and in the periodontal membrane in close proximity to the root surface of human primary and permanent teeth. Materials and methods. The material comprised extracted human teeth (11 primary teeth and six permanent teeth) from 10 different patients. Paraffin sections were prepared of each tooth and sections of each tooth were immunohistochemically stained with antibodies specific for membrane-bound RANKL and RANK. Results. The root surface and the periodontal membrane in close proximity to the root surface did not show immunoreactivity for RANKL. RANKL was only located in odontoblasts and in cells along denticles in one primary tooth. RANK was located in mononuclear cells in the pulp and in multinucleated odontoclasts along resorbed root surfaces and along resorbed dentin surfaces in the pulp in primary teeth and one permanent tooth. Conclusions. This study demonstrated RANK positivity in resorption areas in primary and permanent teeth. RANKL was positive in the pulp of one primary tooth. RANK expression in odontoclasts and RANKL expression in the pulp may indicate that RANK/RANKL play a role during resorption.     

促进撕脱性损伤牙延期再植后牙周愈合的研究进展#br#

牙撕脱性损伤是牙外伤中预后较差的一种,目前对于恒牙撕脱性损伤的治疗一般采用牙再植术,再植时根面牙周组织活性对其预后至关重要。临床调查显示,撕脱性损伤牙再植多为延期再植,离体牙根面牙周膜在干燥状态下脱水坏死是导致术后病理性牙根吸收的主要原因。国际牙外伤协会建议在延期再植时采取适当措施,促进再植牙的牙周愈合再生,减少病理性吸收,延长再植牙使用寿命。文章结合2020版国际牙外伤协会撕脱性损伤牙治疗指南对现有促进撕脱性损伤牙延期再植后牙周愈合相关研究做一综述,包括根面处理、药物及干细胞治疗在牙再植术中的应用。     

Histopathological evaluation of the effects of variable extraoral dry times and enamel matrix proteins (enamel matrix derivatives) application on replanted dogs' teeth

The extra‐alveolar dry period and storage medium in which the tooth was kept prior to replantation remain the critical factors affecting the survival and regeneration of the damaged periodontium. When the replantation is delayed, replacement root resorption is the most common complication following replantation of an avulsed tooth. The aim of this histological study was to evaluate the periodontal healing of replanted dogs' teeth after 20 min (short) and 60 min (long) extraoral dry time with and without the application of enamel matrix proteins. Eighty mature premolar roots (40 teeth) maxillary and mandibular premolars were extracted, the root canals were accessed, instrumented, and filled using a lateral condensation technique, and the access cavity was restored with amalgam. Each root was randomly assigned to one of experimental groups: Groups I and II: Roots were replanted after an extraoral dry time of 20 min. In group II, Emdogain^® (Biora, Malmo, Sweden) was applied directly to the external root surface with complete coverage. Groups III and IV: Roots were replanted after an extraoral dry time of 60 min. In group IV, Emdogain^® was applied to the whole external root surface before replantation. Roots that replanted within a total extraoral dry time of 10 min were used as negative controls, while those replanted after 90 min of extraoral dry time were assigned as positive controls. After 4 months, the dogs were euthanized, and the maxillary and mandibular processes were processed for histology and microscopically evaluated. Statistical analysis showed no significant differences (P = 0.1075) among the experimental groups. The results of this study show that 20 min of extraoral dry time is as detrimental to the PDL cells as 60 or 90 min of extraoral dry time, with avulsed dogs' teeth, even when replanted with an inductive material such as EMD. This study provides strong evidence in relation to the threshold of the extraoral dry time of avulsed teeth, suggesting that the extraoral dry time threshold of PDL cell viability is significantly less than that which current guidelines promote.     

Effect of root surface treatment with propolis and fluoride in delayed tooth replantation in rats

Abstract – Replantation is an acceptable option for treatment of an avulsed permanent tooth. Nevertheless, an extended extraoral period damages the periodontal ligament and results in external root resorption. The purpose of this study was to assess by histologic and histometric analysis, the influence of propolis 15% (natural resinous substance collected by Apis mellifera bees from various plants) and the fluoride solution used as root surface treatment on the healing process after delayed tooth replantation. Thirty Wistar (Rattus norvegicus albinus) rats were submitted to extraction of their upper right incisor. The teeth were maintained in a dry environment for 60 min. After this, the pulp was extirpated and the papilla, enamel organ and periodontal ligament were removed with scalpel. The teeth were divided into three experimental groups: Group I – teeth immersed in 20 ml of physiologic saline; Group II – teeth immersed in 20 ml of 2% acidulated phosphate sodium fluoride; Group III – teeth immersed in 20 ml of 15% propolis. After 10 min of immersion in the solutions, the root canals were dried and filled with calcium hydroxide paste and the teeth were replanted. The animals were euthanized 60 days after replantation. The results showed that similar external root resorption was seen in the propolis and fluoride groups. Teeth treated with physiologic saline tended to have more inflammatory root resorption compared with those treated with fluoride or propolis. However, the comparative analysis did not reveal statistically significant differences (P > 0.05) between the treatment modalities when used for delayed tooth replantation.     

The effect of intracanal Ledermix on root resorption of delayed-replanted monkey teeth

Abstract – Progressive root resorption is one of the common sequelae in replanted teeth, which is detrimental to their long‐term prognosis. Ledermix paste, with its composition of triamcinolone acetonide and demethylclortetracycline, has been shown to inhibit inflammation and the associated hard tissue resorption. This study evaluated the effect of immediate intracanal Ledermix on root resorption of delayed‐replanted monkey teeth. A total of 36 roots were root canal treated. For the experimental group, intracanal Ledermix was placed prior to extraction and replantation after 1‐h bench dry. The positive control group was root filled and replanted after 1 h while the negative control group was root filled and replanted immediately. The monkeys were sacrificed after 12 weeks. The H&E histological tissue specimens were prepared and evaluated using a method modified from that of Andreasen's morphometric analysis, as favorable or complete healing and unfavorable healing, comprising inflammatory root resorption and replacement resorption. The results were analyzed using Kruskal–Wallis and Mann–Whitney U‐tests as well as Wilcoxon signed ranks test. The negative control group produced highly significant favorable healing and unfavorable healing as compared to the Ledermix group (P = 0.000). The Ledermix group only showed significantly higher occurrence of complete healing (35.46%) compared to the positive control group (16.58%) (P = 0.037) but there were no significant differences in the inflammatory root resorption and replacement resorption. Nevertheless, when the latter two unfavorable healing patterns were combined, there was a significantly lower overall unfavorable healing in the Ledermix group (64.54%) when compared to the positive control group (83.43%) (P = 0.037). This unfavorable healing outcome in the Ledermix group, however, was not significantly different from the favorable healing outcome with the same treatment modality (P = 0.110).     

Short-term vs long-term calcium hydroxide therapy after immediate tooth replantation: a histomorphometric study in monkey's teeth

Abstract – Endodontic treatment is an important step of tooth replantation protocols, but the ideal moment for definitive obturation of replanted teeth has not yet been established. In this study, a histomorphometric analysis was undertaken to evaluate the repair process on immediate replantation of monkey’s teeth after calcium hydroxide (CH) therapy for 1 and 6 months followed by root canal filling with a CH‐based sealer (Sealapex^®). The maxillary and mandibular lateral incisors of five female Cebus apella monkeys were extracted, kept in sterile saline for 15 min, replanted and splinted with stainless steel orthodontic wire and composite resin for 10 days. In Group I (control), definitive root canal filling was performed before tooth extraction. In Groups II and III, CH therapy started after removal of splint, and definitive root canal filling was performed 1 and 6 months later, respectively. The animals were euthanized 9 months after replantation, and specimens were processed for histomorphometric analysis. In all groups, epithelial attachment occurred at the cementoenamel junction or very close to this region; the areas of resorption on root surface had small extension and depth and were repaired by newly formed cementum; and the periodontal ligament was organized. Statistical analysis of the scores obtained for the histomorphometric parameters did not show any statistically significant difference (P = 0.1221) among the groups. The results suggests that when endodontic treatment is initiated 10 days after immediate replantation and an antibiotic regimen is associated, definitive root canal filling can be performed after a short‐term CH therapy.     

脱位再植牙牙髓不同处理方法对比研究

目的 探讨脱位再植牙牙髓治疗的最佳方法。方法 61例67颗再植牙随机分为四组，A组：术前不做牙髓治疗直接再植，出现牙髓病变时常规根充，B组：术前去髓，根充碘仿氢氧化钙，（Metapaste)半年后常规根充，C组；术前去髓，根充氢氧化钙，半年后常规根充，D组；术前去髓常规根充，结果 当牙脱位时间超过30分钟后，术前牙髓治疗组的疗效显著优于术后牙髓治疗组。术前去髓充入根管过渡性药物氢氧化钙或碘仿氢氧化钙组的疗效显著优于即刻常规根管治疗组，单纯使用氢氧化钙与使用Metapaste做根管过渡性药物，二者间疗效无显著性差异。结论 牙脱位时间大于30分钟后，术前去髓，先充入氢氧化钙类根管过渡性药物，半年后行根充糊剂加牙胶尖永久充填为较理想的牙髓治疗方法。     

Long‐term retention of avulsed maxillary permanent incisors replanted after prolonged non‐physiological storage

Ankylosis and external replacement resorption (ERR) are two typical biological responses to delayed replantation of avulsed teeth in cases where adequate root canal treatment is performed. The patient's growth stage affects the progression of root resorption and the long‐term outcome of the affected teeth. This case report describes the long‐term outcome of an 18.5‐year‐old patient following an accident in which both of his maxillary central incisors were avulsed and replanted after four hours of non‐physiological storage. ERR and ankylosis of teeth 11 and 21 were detected clinically and radiographically during the second year of follow‐up. Sixteen years after replantation, replacement resorption was progressing very slowly, enabling functional tooth retention with favorable esthetics. Young adults, with delayed replantation of avulsed teeth, may benefit from tooth retention with slow ERR.     

Characteristics of avulsed permanent teeth treated at Beijing Stomatological Hospital

Abstract – Prevention of dental injury is considered to be more important than its treatment. A study was established to reduce the prevalence and the complications of tooth avulsion. Aim: The aim of this study was to investigate the characteristics of tooth avulsion of permanent teeth among patients that visited the Emergency Department of Beijing Stomatological Hospital in China. Materials and methods: A retrospective analysis was performed of the dental records of 88 patients with 120 avulsed permanent teeth between 7 and 75 years old who had attended the Emergency Department of Beijing Stomatological Hospital in China during the period 1 July 2008 until 30 June 2009. Results: In 88 examined patients, the number of avulsed permanent teeth was 120. In 63 (71.6%) patients, in total 85 avulsed teeth were treated with replantation. In 18 (28.6%) patients, the avulsed teeth were stored in dry media. In only eight cases (12.7%), the avulsed teeth were replanted within 30 min. In approximately half of the cases (49.2%), the replanted teeth were fixed with stainless steel splint and a composite resin. Conclusions: It was evident from this study that there were delayed tooth replantations in many tooth avulsion cases. Thus, educational programs should be conducted to create awareness about the importance of immediate replantation, which will entail better prognosis of traumatic avulsed permanent tooth.     

Influence of enamel matrix derivative (Emdogain®) and sodium fluoride on the healing process in delayed tooth replantation: histologic and histometric analysis in rats

Abstract – Although it has already been shown that enamel matrix derivative (Emdogain^®) promotes periodontal regeneration in the treatment of intrabony periodontal defects, there is little information concerning its regenerative capacity in cases of delayed tooth replantation. To evaluate the alterations in the periodontal healing of replanted teeth after use of Emdogain^®, the central incisors of 24 Wistar rats (Rattus norvegicus albinus) were extracted and left on the bench for 6 h. Thereafter, the dental papilla and the enamel organ of each tooth were sectioned for pulp removal by a retrograde way and the canal was irrigated with 1% sodium hypochlorite. The teeth were assigned to two groups:in group I, root surface was treated with 1% sodium hypochlorite for 10 min (changing the solution every 5 min), rinsed with saline for 10 min and immersed in 2% acidulated‐phosphate sodium fluoride for 10 min; in group II, root surfaces were treated in the same way as described above, except for the application of Emdogain^® instead of sodium fluoride. The teeth were filled with calcium hydroxide (in group II right before Emdogain^® was applied) and replanted. All animals received antibiotic therapy. The rats were killed by anesthetic overdose 10 and 60 days after replantation. The pieces containing the replanted teeth were removed, fixated, decalcified and paraffin‐embedded. Semi‐serial 6‐μm‐thick sections were obtained and stained with hematoxylin and eosin for histologic and histometric analyses. The use of 2% acidulated‐phosphate sodium fluoride provided more areas of replacement resorption. The use of Emdogain^® resulted in more areas of ankylosis and was therefore not able to avoid dentoalveolar ankylosis. It may be concluded that neither 2% acidulated‐phosphate sodium fluoride nor Emdogain^® were able to prevent root resorption in delayed tooth replantation in rats.     

Root surface treatment using diode laser in delayed tooth replantation: radiographic and histomorphometric analyses in rats

Abstract – Background aim: The aim of this study was to evaluate, by radiographic and histomorphometric analyses, the effects of high‐power diode laser irradiation on the root surfaces of delayed replanted rat teeth. Material and methods: Maxillary right incisors were extracted from 60 Wistar rats and kept dry for 60 min. Subsequently, the root canals were prepared and filled with calcium hydroxide paste. According to the root surface treatment before the replantation, the teeth were assigned to four groups (n = 15): G1 (negative control) – no root surface treatment; G2 (positive control) – treated with 2% sodium fluoride solution; G3 – irradiated with a high‐power diode laser (810 nm, continuous mode, 1.0 W, 30 s); and G4 – irradiated with a diode laser using the same parameters as those used for G3 but in pulsed mode. The rats were euthanized after 15, 30, and 60 days of replantation. The specimens were digitally radiographed and processed for histomorphometric analysis to determine the average root resorption areas and to evaluate the histological events. Results: The percentage of root resorption was in the following order: G1 > G2 > G4 > G3. Both histomorphometric and radiographic analyses showed significantly lower means (P < 0.05) of the occurrence of root resorption in the irradiated groups (G3 and G4) when compared to the control groups (G1 and G2). Replacement resorption and ankylosis were observed in histological sections only after 30 and 60 days; however, such events were not observed in G3. Conclusion: Root surface treatments with high‐powered diode laser irradiation prior to delayed replantation reduced the occurrence of external root resorption compared to no treatment or sodium fluoride treatment at up to 60 days.