Effect of ELVAX polymer subgingival implants with echistatin on extracted and reimplanted rats' teeth.

To investigate the effect of ELVAX polymer subgingival implants incorporated with echistatin peptide on incisor reimplanted tooth in rats. Forty-two male Wistars rats were divided into two groups: echistatin-treated rats (E) and control rats (C). The animals had their right maxillary incisors extracted and treated according to the International Association of Dental Traumatology replantation protocol. The extra-alveolar dry period was 30 and 60 min, and the post-surgical experimental periods were 15, 60, and 90 days. The samples were stained with H&E and analyzed for the presence of an inflammatory response, incidence of resorptions, and dental ankylosis. Results were statistically analyzed (p < 0.05). The presence of inflammatory resorption was significantly higher in group C at 30 and 60 min extra-alveolar time, in the 15-day postoperative period as compared with the E group (p < 0.05). Dental ankylosis was significantly more prevalent in group E in 30 min extra-alveolar time and 15 days postoperative period (p < 0.05). However, in 60 min extra-alveolar time and 60 days postoperative period, dental ankylosis was more prevalent in C group (p < 0.05). The use of ELVAX subgingival implants with echistatin demonstrated therapeutic potential in preventing the experimental resorption process after replantation of maxillary incisors in rats.

Analysis of the cells isolated from epithelial cell rests of Malassez through single-cell limiting dilution.

The epithelial cell rests of Malassez (ERM) are essential in preventing ankylosis between the alveolar bone and the tooth (dentoalveolar ankylosis). Despite extensive research, the mechanism by which ERM cells suppress ankylosis remains uncertain; perhaps its varied population is to reason. Therefore, in this study, eighteen unique clones of ERM (CRUDE) were isolated using the single-cell limiting dilution and designated as ERM 1-18. qRT-PCR, ELISA, and western blot analyses revealed that ERM-2 and -3 had the highest and lowest amelogenin expression, respectively. Mineralization of human periodontal ligament fibroblasts (HPDLF) was reduced in vitro co-culture with CRUDE ERM, ERM-2, and -3 cells, but recovered when an anti-amelogenin antibody was introduced. Transplanted rat molars grown in ERM-2 cell supernatants produced substantially less bone than those cultured in other cell supernatants; inhibition was rescued when an anti-amelogenin antibody was added to the supernatants. Anti-Osterix antibody staining was used to confirm the development of new bones. In addition, next-generation sequencing (NGS) data were analysed to discover genes related to the distinct roles of CRUDE ERM, ERM-2, and ERM-3. According to this study, amelogenin produced by ERM cells helps to prevent dentoalveolar ankylosis and maintain periodontal ligament (PDL) space, depending on their clonal diversity.

Periodontal ligament repair after active splinting of replanted dogs' teeth.

BACKGROUND/AIM: The high rate of root resorption resulting from tooth replantation represents a serious clinical problem. In order to prevent ankylosis and replacement resorption, the contemporary literature highlights the importance of using a flexible stabilization for traumatized teeth. For this purpose, orthodontic devices may be promising for obtaining a better prognosis and periodontal repair. The aim of this study was to evaluate the effect of an active splinting protocol with controlled force in dog's teeth following replantation. MATERIAL AND METHODS: Sixty premolar roots from three dogs were used. They were submitted to endodontic treatment, hemisected, atraumatically extracted and subsequently replanted. They were divided into four groups: Passive Stabilization (n = 20)-after 20 min in a dry medium; Active Stabilization (n = 20)-after 20 min in a dry medium; Negative control (n = 10)-immediate replantation and passive Stabilization; and Positive control (n = 10)-90 min of extra-alveolar time and passive Stabilization. The samples were collected and submitted to histologic processing. They were then evaluated for the count of inflammatory cells, expression of neurotrophin 4, osteoclasts, apoptotic cells and collagen fibres. The results were submitted to ANOVA or Kruskal-Wallis statistical tests followed by Tukey or Dunn post-tests (α = 5%). RESULTS: Passive Stabilization with orthodontic brackets without traction used after replantation had the highest number of inflammatory cells (p = .0122), osteoclasts (p = .0013) and percentage of collagen fibres in the periodontal ligament (p < .0001) when compared to Active Stabilization with orthodontic brackets applying amild tensile force. Neurotrophin 4 had no statistically significant difference (p = .05), regardless of the treatment. The apoptotic cells count revealed statistical differences (p < .0001) between Active Stabilization (189.70 ± 47.99) and Positive Control (198.90 ± 88.92) when compared to Passive Stabilization (21.19 ± 32.94). CONCLUSION: The active splinting protocol using orthodontic appliances generating a light and controlled force favoured periodontal ligament repair of replanted teeth.

Effect of periodontal ligament removal with gauze prior to delayed replantation in rabbit incisors on rate of replacement resorption.

BACKGROUND/AIM: Delayed (dry storage > 60 minutes) replantation results in ankylosis and replacement resorption. It has been suggested to remove the non-viable periodontal ligament before replantation to possibly reduce the rate of replacement resorption. However there has been no study on the rate of replacement resorption after such measures. The aim of this study was to investigate if there was any difference in the rate of replacement resorption by either removing the periodontal ligament (PDL) with gauze or not removing PDL in teeth subjected to delayed replantation followed by healing for 2 or 6 weeks. MATERIALS AND METHODS: Maxillary central incisors were extracted in 8 rabbits. In the right central incisors, the necrotic PDL was removed by dry gauze over the root surface. In the left eight extracted teeth PDL was left on the root surface. All extracted teeth were left to dry for 60 minutes. Extra-oral root canal treatment was performed before replantation. The rabbits were sacrificed after 2 weeks and 6 weeks respectively. Histologic processing and evaluation was done. RESULTS: In the 2 weeks group, all teeth showed ankylosis. The cementum was intact, and fusion of the bone and root was generally seen without resorption of the root, whereas in the 6 weeks group regardless of whether PDL had been kept or not, ankylosis and osseous replacement of the dentin was seen. There was no evidence of inflammatory infiltrate in the sections examined. CONCLUSION: Removal of PDL prior to delayed replantation may result in some initial protection of the cementum during the first few weeks. However, over longer times there seems to be neither protection of the dentin from ankylosis and osseous replacement, nor any influence on the rate of replacement resorption.

Etiology, Classification and Management of Ectopic Eruption of Permanent First Molars.

Ectopic eruption of a permanent tooth involves abnormal resorption of a portion or all of the adjacent primary tooth. Among the most commonly ectopically erupted teeth are the permanent first molars. Ectopically erupting molars may require intervention to allow for full eruption, or they may spontaneously self-correct and erupt into occlusion. Decisions regarding the necessity of intervention, its ideal timing, and intervention type are multifactorial. Treatment options for the ectopically erupting permanent first molar include the elastomeric separator, brass wire, pre-fabricated clip separator, custom made appliances (Humphrey appliance, Halterman appliance), or extraction of the primary molar. Early intervention when indicated can ensure proper full eruption of the permanent first molar and prevent mesial angulation, arch perimeter loss, tooth impaction and ankylosis. Two cases are described that manage ectopic eruption of the permanent first molar.

Effect of fibroblast growth factor and enamel matrix derivative treatment on root resorption after delayed replantation.

BACKGROUND: Periodontal ligament (PDL) healing and long term prognosis of replanted avulsed teeth should rely on several factors including length of extra-oral dry time and type of the storage medium. The status of periodontal ligament is critical for the healing of replanted teeth. Different substances have been used for root surface treatment to promote formation of PDL and increase the survival of avulsed teeth submitted to replantation. AIM: The purpose of this study was to assess the effect of recombinant basic fibroblast growth factor 2 (bFGF) and enamel matrix derivative (EMD) on root resorption after delayed replantation. DESIGN: 18 freshly extracted single-rooted incisor and premolar teeth were extracted from the beagle dogs and immersed in whole bovine milk for 45 and 60 min (n = 3 each). Following storage period, sockets washed and teeth were treated with bFGF and EMD and replanted into the sockets. After 8 weeks, dogs were sacrificed, specimens processed to 4-µm thick serial sections for histopathologic examination and morphometric assessments. Thus, the proportions of the roots that exhibited signs of surface resorption, inflammatory resorption, and replacement resorption, that is, ankylosis and normal PDL were noted. RESULTS: The percentage of root resorption was in the following order: EMD>milk>bFGF for 45 min and milk>EMD>bFGF for 60 min. For all groups, teeth stored 60 min showed significantly higher incidence of PDL resorption than those stored for 45 min (P < 0.01). The highest incidence of replacement resorption was observed in teeth treated with EMD for 60 min. After 8 weeks, the least resorption was found in bFGF-treated group (P < 0.01). CONCLUSIONS: The findings of this study suggest that use of bFGF favored the formation of new periodontal ligament; prevent ankylosis and resorption process following delayed replantation of teeth while EMD shows replacement resorption, which may turn to ankylosis.

Delayed tooth replantation: MTA as root canal filling.

MTA has been investigated as a root-end filling material. Its mechanism of action has some similarities to that of Ca(OH)2. The purpose of this study was to evaluate the repair process taking place in the delayed replantation of monkey teeth using calcium hydroxide and MTA as root canal filling materials. Five monkeys had their lateral incisors extracted and bench-dried for 60 minutes. After root canal preparation, the teeth were assigned to two groups according to root canal filling material: I, calcium hydroxide; and II, MTA. The same treatment sequence was followed for both groups: coronal seal, periodontal ligament removal, immersion of the tooth in 2% acidulated-phosphate sodium fluoride, irrigation of the socket with saline and replantation. Both groups exhibited replacement resorption, areas of ankylosis and absence of inflammatory root resorption. Statistically similar results (p > 0.05) were observed for both groups regarding replacement root resorption, but the groups differed significantly (p < 0.05) regarding the occurrence of ankylosis. MTA may be a viable clinical option for filling teeth submitted to delayed replantation, and is an acceptable option for treating replanted permanent teeth in order to prevent tooth resorption, particularly when dressing changes are not possible.

A histological and micro-CT investigation in to the effect of NGF and EGF on the periodontal, alveolar bone, root and pulpal healing of replanted molars in a rat model - a pilot study.

BACKGROUND: This study aims to investigate, utilising micro-computed tomography (micro-CT) and histology, whether the topical application of nerve growth factor (NGF) and/or epidermal growth factor (EGF) can enhance periodontal, alveolar bone, root and pulpal tissue regeneration while minimising the risk of pulpal necrosis, root resorption and ankylosis of replanted molars in a rat model. METHODS: Twelve four-week-old male Sprague-Dawley rats were divided into four groups: sham, collagen, EGF and NGF. The maxillary right first molar was elevated and replanted with or without a collagen membrane impregnated with either the growth factors EGF or NGF, or a saline solution. Four weeks after replantation, the animals were sacrificed and the posterior maxilla was assessed using histological and micro-CT analysis. The maxillary left first molar served as the control for the corresponding right first molar. RESULTS: Micro-CT analysis revealed a tendency for all replanted molars to have reduced root length, root volume, alveolar bone height and inter-radicular alveolar bone volume. It appears that the use of the collagen membrane had a negative effect while no positive effect was noted with the incorporation of EGF or NGF. Histologically, the incorporation of the collagen membrane was found to negatively affect pulpal, root, periodontal and alveolar bone healing with pulpal inflammation and hard tissue formation, extensive root resorption and alveolar bone fragmentation. The incorporation of EGF and NGF did not improve root, periodontal or alveolar bone healing. However, EGF was found to improve pulp vascularisation while NGF-improved pulpal architecture and cell organisation, although not to the level of the control group. CONCLUSIONS: Results indicate a possible benefit on pulpal vascularisation and pulpal cell organisation following the incorporation of EGF and NGF, respectively, into the alveolar socket of replanted molars in the rat model. No potential benefit of EGF and NGF was detected in periodontal or root healing, while the use of a collagen membrane carrier was found to have a negative effect on the healing response.

Ankylosis of impacted canines: a retrospective post-surgical study.

Ankylosis is generally discovered following resistance to orthodontic displacement of an impacted canine. This retrospective study, drawing on direct perioperative observation of impacted teeth and of their sites, is intended, among other things, to analyze the causes of resistance to orthodontic movement and to report on the therapeutic interest of the surgical tooth displacement technique in this type of clinical situation. We demonstrate that primary coronal ankylosis can be detected by the orthodontic practitioner using radiographic records, that cervical ankylosis consequent to operative trauma during release is necessarily unpredictable and that it should be suspected when the tooth resists traction for more than 3 months in the absence of any other obvious cause of resistance. Hence, the risk of ankylosis linked to the level of surgical difficulty increases with the depth of coronal submergence within the bone. Moreover, the immediate placement of traction following release reduces the risk of ankylosis. In addition, temporarily suspending traction is a risk factor for secondary apical ankylosis. Finally, surgical positioning should be borne in mind as the final effective option when faced with any form of dental retention.

Effect of basic fibroblast growth factor on root resorption after delayed autotransplantation of tooth in dogs.

OBJECTIVES: The aim of this study was to investigate the effect of basic fibroblast growth factor (FGF-2) on root resorption after delayed autotransplantation in dogs. STUDY DESIGN: Mandibular second and third premolars of beagle dogs were extracted to create sites for autotransplantation. After 2 months, in the experimental sites the first and fourth mandibular premolars were extracted and air dried before autotransplantation with the application of recombinant FGF-2; the control sites received teeth without FGF-2. At 2, 4, or 8 weeks after surgery, the animals were killed and specimens collected and processed for histologic examination. RESULTS: Autotransplantation with FGF-2 yielded formation of new periodontal ligament-like tissues with inserting collagen fibers, associated cementum, and bone. The occurrence of replacement resorption in the FGF-2 treated group was significantly lower than in the control group (P < .01). CONCLUSIONS: It was demonstrated that topical application of FGF-2 reduced the occurrence of ankylosis and root resorption after delayed autotransplantation in this experimental model.

Periodontal healing following avulsion and replantation of teeth: a multi-centre randomized controlled trial to compare two root canal medicaments.

BACKGROUND: Non-setting calcium hydroxide (Ultracal XS(®) ) is recommended by the International Association of Dental Traumatology as the initial medicament following avulsion and replantation for mature teeth. There is experimental evidence to suggest Ledermix(®) , placed as an alternative inter-visit dressing may improve periodontal healing. AIM: This study investigated, using a multi-centre randomized controlled trial, the effect of two root canal medicaments, Ledermix(®) and Ultracal XS(®) , on periodontal healing of avulsed and replanted teeth. MATERIAL AND METHODS: Children were recruited if they fulfilled all inclusion criteria. Treatment followed a standardized protocol. Assessment of periodontal healing or ankylosis was made clinically and radiographically by an experienced, 'blinded', clinician at 12months. RESULTS: Over 200 patients were assessed for eligibility at five centres. Twenty-nine patients were eligible for inclusion. Final analysis involved 22 patients with 27 teeth. Ankylosis was detected in four of the 12 teeth in the Ledermix(®) group and nine of 15 in the Ultracal XS(®) group. No significant difference between medicaments was found in the proportion of teeth or patients showing periodontal healing. DISCUSSION: There was no significant difference in periodontal healing between the two medicaments at either a tooth or patient level. The numbers recruited fell short of an estimated power calculation. For patients meeting the inclusion criteria and completing the trial, periodontal healing was seen in 52% of teeth at the 12-month assessment between both groups. The only factor found to significantly influence the periodontal outcome was dry time.

Effect of early orthodontic force on periodontal healing after autotransplantation of permanent incisors in beagle dogs.

BACKGROUND: Masticatory stimulation during the healing period may promote periodontal ligament healing. The aim of the present study is to investigate the effect of orthodontic force on the periodontal healing of autotransplanted teeth. METHODS: A total of 30 teeth from four dogs were endodontically treated to prevent subsequent inflammatory root resorption. The teeth were atraumatically extracted and autotransplanted to the other side of the same jaw. A continuous 50-g orthodontic force was applied during the first, second, and fourth weeks after autotransplantation. After 8 weeks, the animals were sacrificed using vital perfusion fixation, and the teeth were histologically prepared and evaluated following the Andreasen method. RESULTS: The application of force in the first, second, and fourth weeks after autotransplantation resulted in a lower occurrence of ankylosis. The first- and second-week loading groups differed significantly from the control group (P <0.05); however, significantly more resorption and less complete healing were observed in the first-week loading group than in the other groups (P <0.05). CONCLUSION: The results of this study demonstrate that orthodontic force promotes periodontal ligament healing and that early force loading may prevent dentoalveolar ankylosis; however, a period of rest of ≥2 weeks is recommended for the autotransplants before loading.

Propolis as storage media for avulsed teeth: microscopic and morphometric analysis in rats.

The maintenance of the avulsed teeth in appropriate media for preserving the cellular viability has been important for repairing the periodontal ligament and preventing the root resorption after tooth reimplantation. Propolis is a substance capable of preserving cellular viability. This study aimed to analyze the propolis substance as a storage media for maintaining the avulsed teeth, besides to determine the ideal time period for keeping the tooth inside it. Thus, 60 maxillary right central incisors of rats were extracted and divided into five groups. In groups I and II, teeth were kept in propolis for 60 min and 6 h, respectively; in group III, teeth were kept in milk for 6 h; in group IV, teeth were kept dry for 60 min; and in group V, they were immediately reimplanted. All teeth had their root canals filled with calcium hydroxide paste. Following, teeth were reimplanted in their sockets. After 15 and 60 days, animals were killed and the obtained samples were processed in laboratory for microscopic and morphometric analyzing. The results showed that the occurrence of inflammatory resorption, dental ankylosis and the formation of the connective tissue parallel to the root surface were similar among groups. It could be verified a greater occurrence of replacement resorption in group IV when comparing to other groups. In groups I and IV, the presence of periodontal ligament-like connective tissue was substantially smaller than the other groups. Regarding to the cementum amount over the root, it could be observed that this was present in smaller amount in groups I and IV. Group II was similar to groups III and IV. Therefore, according to the results of this study, the use of propolis as a storage media for maintaining avulsed teeth could be highlighted, and the 6-h period was more appropriate than the 60-min period.

Effect of recombinant basic fibroblast growth factor on reimplanted teeth in beagle dogs.

OBJECTIVES: This study assessed the effect of recombinant fibroblast growth factor (FGF-2) on reimplanted teeth. STUDY DESIGN: Premolars were reimplanted in dogs. Roots on the left side of the mandible were treated with FGF-2, whereas roots on right side served as controls. At 2, 4, or 8 weeks after treatment, animals were humanely killed and specimens collected and processed for histopathologic examination. RESULTS: After 2 weeks, proliferating cell nuclear antigen-positive cell ratios in the experimental group were significantly greater than those in the control group (P < .01). After 4 and 8 weeks, the experimental group showed formation of new cementum. Moreover, incidence of replacement resorption in the experimental group was significantly lower than that in the control group (P < .01). CONCLUSION: The results indicate that FGF-2 promotes formation of new periodontal ligament and prevents ankylosis and root resorption following reimplantation of teeth.

Intracanal bisphosphonate does not inhibit replacement resorption associated with delayed replantation of monkey incisors.

Progressive replacement resorption following delayed replantation of avulsed teeth has proved to be an intractable clinical problem. A wide variety of therapeutic approaches have failed to result in the predictable arrest of resorption, with a good long-term prognosis for tooth survival. Bisphosphonates are used in the medical management of a range of bone disorders and topically applied bisphosphonate has been reported to inhibit root resorption in dogs. This study evaluated the effectiveness of a bisphosphonate (etidronate disodium) as an intracanal medicament in the root canals of avulsed monkey teeth, placed before replantation after 1 h of extraoral dry storage. Incisors of six Macaca fascicularis monkeys were extracted and stored dry for 1 h. Teeth were then replanted after canal contamination with dental plaque (negative control) or after root canal debridement and placement of etidronate sealed in the canal space. A positive control of calcium hydroxide placed 8-9 days after replantation was also included. All monkeys were sacrificed 8 weeks later and block sections were prepared for histomorphometric assessment of root resorption and periodontal ligament status. Untreated teeth showed the greatest extent of root resorption (46% of the root surface), which was predominantly inflammatory in nature. Calcium hydroxide treated teeth showed the lowest overall level of resorption (<30% of the root surface), while the bisphosphonate-treated group was intermediate (39%). Ankylosis, defined as the extent of the root surface demonstrating direct bony union to both intact and resorbed root surface, was the lowest in the untreated control group (15% of the root surface), intermediate in the calcium hydroxide group (27%) and the highest in the bisphosphonate group (41%). Bony attachment to the tooth root was divided approximately equally between attachment to intact cementum and to previously resorbed dentin. Overall, bisphosphonate resulted in a worse outcome than calcium hydroxide in terms of both root resorption and ankylosis.

Transplantation of human tooth with proliferating periodontal tissue--long-term clinical follow-up study--.

A case report is presented on transplantation of a left third molar to replace a right second molar lost due to large furcation perforation. Two weeks after surgery, a reentry surgical procedure was performed on the furcation defect of the second molar to remove membrane and retrieve proliferating periodontal tissue. The left third molar and proliferating periodontal tissue were then transplanted into the bone defect of the right second molar. Radiographically, the transplanted tooth showed no root resorption over a 3-year period. The results indicate that teeth replanted with proliferating periodontal tissue have a favorable long-term prognosis.

The influence of occlusal stimuli on basic fibroblast growth factor expression in the periodontal healing of replanted teeth.

Occlusal stimuli and the periodontal healing of replanted teeth have been reported to be related. However, the mechanism for preventing dentoalveolar ankylosis remains unclear. Basic fibroblast growth factor (bFGF/FGF-2) is considered as a key factor in wound healing. The purpose of this study was to evaluate the relationship between occlusal stimuli, bFGF, and the periodontal healing after tooth replantation. Five-week-old male rats were divided into non-occluded, occluded, and recovery groups. The right maxillary first molars were replanted in all groups, and the left maxillary first molars in the 2-week occluded group without replantation were served as nontreated. An anterior bite plate was attached to the maxillary and mandibular incisors to produce occlusal hypofunction in the non-occluded group and was then removed after 1 week in the recovery group. Histological observations were performed after 1 and 2 weeks of the experimental period. After 2 weeks, the non-occluded group had detectable ankylosis and obvious periodontal tissue stricture. Meanwhile, the occluded and recovery groups showed enlarged and thickened periodontia without ankylosis. The number of bFGF-positive cells in the occluded and recovery groups significantly increased as compared to in the non-occluded group. These results suggest that occlusal stimuli enhance the production of bFGF in the periodontal healing of replanted teeth and prevent dentoalveolar ankylosis.

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

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-microm-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.