Survival and complication analyses of avulsed and replanted permanent teeth

Effect of intra-alveolar delivery of Frondoside A on inflammatory response of delayed tooth replantation

BACKGROUND/AIM

Frondoside A is a sea cucumber extract which is well known for its anti-inflammatory and immunomodulatory properties. The purpose of this study was to evaluate the effect of Frondoside A application in the alveolar socket on inflammatory responses after delayed replantation in rat teeth.

MATERIALS AND METHODS

Human periodontal ligament cells were cultured and exposed to Frondoside A. Cell-counting kit-8 assay was performed to evaluate the cell viability and nitric oxide assay was performed to assess the anti-inflammatory effect of Frondoside A. Molars were extracted from 32 Sprague-Dawley rats and randomly divided into control and Frondoside A groups. After 30 min of extra-oral dry time, molars were replanted. In the Frondoside A group, Frondoside A solution was applied in the alveolar socket before replantation. The animals were sacrificed after 28 days and histologically and immunohistochemically evaluated.

RESULTS

0.5 μM Frondoside A showed higher cellular viability at 6 h and lower production of nitric oxide compared with other Frondoside A solutions (p < .05). The Frondoside A group demonstrated lower inflammatory resorption scores in both middle 1/3 and apical 1/3 of root compared to the control group (p < .05). The Frondoside A group showed lower levels of expression in both cathepsin K and CD45 compared with the control group (p < .05).

CONCLUSIONS

Within the limits of this study, intra-alveolar delivery of Frondoside A alleviates inflammatory root resorption in delayed replantation of rat teeth.

Controversies in Dental Traumatology

The management of traumatic dental injuries is more a shade of gray than it is black and white because not all treatment procedures used for dental trauma management are fully evidence based. This chapter has highlighted some of the gray areas related to the treatment and outcome of traumatic dental injuries. Significant controversies in the management of luxation and avulsive injuries have been brought out. Adjunctive treatment such as antibiotic usage, tetanus vaccination, and pain management is also addressed.

Effect of icariin surface treatment on the resorption of denuded roots after replantation in rat

AIM

Limiting the incidence of resorption associated with delayed replantation of avulsed teeth is critical for long-term tooth survival. In this study, we assessed whether icariin, a natural product with anti-osteoclastic properties, could reduce root resorption in a rat model of tooth replantation.

METHODOLOGY

Cytocompatibility of icariin (10, 20, 40 and 80 μM) was evaluated by CCK-8 proliferation assay in vitro, and an osteoclastogenesis assay was performed to evaluate the effect of icariin on the differentiation of rat bone marrow macrophages and human peripheral blood monocytes into tartrate-resistant acid phosphatase-stained (TRAP+ ) multinucleated giant cells (MNGCs). Differentiation of human periodontal ligament stem cells (hPDLSCs) treated with icariin (10 μM) was also evaluated at 5, 10 and 21 days of osteogenic induction. The first maxillary molars of five-week-old male Sprague-Dawley rats were extracted, denuded of PDL, then treated either with neutralized collagen solution (Carrier control) or icariin in collagen (3 μg/μL) before replantation into their sockets. The animals were euthanized 2 weeks post-surgery for micro-computed tomography (micro-CT) imaging and histological analyses.

RESULTS

Icariin was cytocompatible and significantly reduced the differentiation of TRAP+ MNGCs in a dose-dependent manner compared to the control. Moreover, icariin enhanced alkaline phosphatase activity, expression of osteogenic marker genes and proteins, and calcium deposition in hPDLSCs. Micro-CT imaging of the replanted samples demonstrated a significantly higher volume of remaining roots in the icariin-treated group than in the control group. Histological analysis revealed a marked number of resorptive lacunae with TRAP activity in the control group, whereas icariin-treated samples showed signs of functional healing and reduced osteoclastic activity.

CONCLUSIONS

Icariin was biocompatible and demonstrated potent anti-osteoclastic and pro-osteogenic properties that reduced resorption and promoted functional healing of denuded roots in a rat maxillary first molar model of replantation. These findings indicate that root surface treatment with icariin may be a clinically relevant and practical method for improving the retention and survival of teeth with compromised PDL after delayed replantation following traumatic avulsion.

The Top 100 Most-Cited Articles on Permanent Teeth Avulsion: A Bibliometric Analysis

INTRODUCTION

Knowledge of bibliometric indices on the avulsion of permanent teeth can help researchers to identify gaps in the literature. The aim of this study was to analyze the bibliometric characteristics of the 100 most-cited articles on the avulsion of permanent teeth.

MATERIALS AND METHODS

Two researchers conducted an unfiltered search in the Core Collection section of the Web of Science (WoS-CC) database. The following data were extracted: position in the citation list, total number and density of citations, title, authors, institution, country, year of publication, journal, keywords, study design, tooth storage medium, and other topics of interest. Bibliometric networks were generated and analyzed using the VOSviewer software. Descriptive analysis and a Poisson regression analysis were performed (P < .05).

RESULTS

The number of citations per article varied between 31 and 407. The average was 70.05, and 13 articles received more than 100 citations. J.O. Andreasen (n = 13) and M. Trope (n = 15) were the authors who contributed most often to publications. The United States was the country with the highest number of articles (n = 31). Authors associated with the University of Copenhagen, Denmark (n = 9) and University of North Carolina, USA (n = 10) showed higher productivity. In vitro/animal model studies were the most frequent study designs (n = 50), and the most-discussed topic of interest was prognosis (n = 47). There was strong clustering among 13 research groups.

CONCLUSION

Observational studies, published by authors from Europe and about prognosis or treatment presented more citation ratio in WoS-CC. Clinical studies on permanent tooth avulsion are needed to increase the quality of scientific evidence and provide insights for health professionals and public policy makers.

Intentional replantation and dental autotransplantation of mandibular posterior teeth: Two case reports

BACKGROUND

Intentional replantation and dental autotransplantation are 2 similar techniques both involving atraumatic tooth extraction, visualization of the root, and replantation. They are considered as the last resort for unsalvageable teeth. The author aims to describe 2 mandibular posterior teeth with serious periapical lesions which are resolved by intentional replantation and dental autotransplantation, respectively.

CASE SUMMARY

In case 1, a 45-year-old male patient received root canal treatment because of a cracked mandible right first molar with periapical lesions. An endodontic file was separated in the apical third of the mesiolingual root canal. After conventional canal filling of the other root canals, the molar was atraumatically extracted. The separated instrument was removed, the mesiolingual root received a retrograde filling and the molar was replanted. At the 3-month follow up, the patient was asymptomatic and the X-ray picture showed no detectable root resorption and ankylosis. In case 2, a 29-year-old woman reported discomfort during occlusal loading after a root canal treatment and a coronal restoration of the mandibular right first molar. Radiographs showed a low-density shadow in the mesial apical and in the root furcation area of the mandibular first molar so the patient was diagnosed as chronic periapical periodontitis. After the removal of the affected tooth, the extraction socket was thoroughly debrided and irrigated. The intact mandibular right third molar with similar dimensions was extracted by minimally invasive procedure and transplanted. The donor tooth was fixed by a fiber-splint for 1 month and a root canal treatment was performed 2 weeks after surgery. After 1 year, clinical and radiographical examination revealed functional and periodontal healing.

CONCLUSIONS

These 2 reports present the successful management of intentional replantation and dental autotransplantation. Both procedures are recommended after nonsurgical endodontic treatment, especially when apical microsurgery is not an option, for example because of difficult accessibility or patient preference.

Avulsion of Permanent Mandibular Incisors: A Report of Two Cases with Pertinent Literature

Introduction. This study reports two rare cases of avulsion of permanent mandibular incisors with their sequelae after being reimplanted by two contrary methods. The relevant literature regarding the avulsion of permanent mandibular incisors is also being discussed. Case Presentation. In Case I, a 9-year-old girl reported an avulsion of the permanent mandibular left lateral incisor that was immediately reimplanted within 20 minutes after injury, whereas in Case II, all four permanent mandibular incisors were avulsed and reimplanted after a prolonged extraoral dry time of 36 hours in an 18-year-old female. Both cases missed their scheduled follow-up visits and were reported after 3.5 years and 7 months, respectively, with severe root and alveolar bone resorption that was confirmed by clinical examination and Intra oral periapical radiograph (IOPA) radiographs. Discussion. Avulsion of permanent mandibular incisors is rare. The similar unfavorable outcome of contrary cases at a variable duration of time after missed follow-up illustrates the role of the appropriate treatment protocol and regular follow-up visits for the long-term success of reimplanted teeth.

Comparative gene expression analysis of stemness between periodontal ligament and umbilical cord tissues in humans

Background/purpose

Due to their regenerative potential, periodontal ligament (PDL) and umbilical cord (UBC) tissues are an attractive potential mesenchymal stem cells (MSCs) source. This study compared the expression patterns of genes related to stemness between fresh PDL and UBC tissues.

Materials and methods

PDL tissues were collected from 38 permanent premolars extracted for orthodontic purposes, and UBC tissues were obtained from three newborns. Each sample was immediately frozen to prevent RNA degradation. cDNA microarray analysis, quantitative real-time polymerase chain reaction (PCR), and immunohistochemical staining were performed. Gene expression patterns associated with dental stemness (DS) and induced pluripotent stemness (iPS) were compared between PDL and UBC tissues.

Results

In the cDNA microarray analyses, the expressions of most iPS genes were greater in the PDL than in the UBC. Meanwhile, the expressions of most DS genes were greater in the UBC than in the PDL. Quantitative real-time PCR analyses showed that the expression levels of matrix metallopeptidase 13 (MMP13), ADAM metallopeptidase domain 22 (ADAM22), vascular cell adhesion protein 1 (VCAM1), and kruppel-like factor 4 (KLF4) genes were greater in the PDL than in the UBC, while the expressions of melanoma cell adhesion molecule (MCAM) and activated leukocyte cell adhesion molecule (ALCAM) were greater in the UBC than in the PDL.

Conclusion

These results suggest that UBC and PDL tissues showed slightly different expression patterns of genes related to stemness, which warrants further investigation to use these tissues for future regeneration and implantation therapies.

Tooth transplantation and replantation: Biological insights towards therapeutic improvements

Transplantation and replantation of teeth are effective therapeutic approaches for tooth repositioning and avulsion, respectively. Transplantation involves transplanting an extracted tooth from the original site into another site, regenerating tissue including the periodontal ligament (PDL) and alveolar bone, around the transplanted tooth. Replantation places the avulsed tooth back to its original site, regenerating functional periodontal tissue. In clinical settings, transplantation and replantation result in favorable outcomes with regenerated PDL tissue in many cases. However, they often result in poor outcomes with two major complications: tooth ankylosis and root resorption. In tooth ankylosis, the root surface and alveolar bone are fused, reducing the PDL tissue between them. The root is subjected to remodeling processes and is partially replaced by bone. In severe cases, the resorbed root is completely replaced by bone tissue, which is called as "replacement resorption." Resorption is sometimes accompanied by infection-mediated inflammation. The molecular mechanisms of ankylosis and root resorption remain unclear, although some signaling mechanisms have been proposed. In this mini-review, we summarized the biological basis of repair mechanisms of tissues in transplantation and replantation and the pathogenesis of their healing failure. We also discussed possible therapeutic interventions to improve treatment success rates.

Management of 3 Avulsed Permanent Teeth: Case Report of a 3-Year Follow-up

Dental avulsion is one of the most serious dental injuries. When the tooth is knocked out, the blood supply to the pulp is interrupted and the periodontal ligament cells are exposed to injuries caused by the external environment. In recent years, research findings have shown the possibility of complete healing under favorable conditions: replanting the tooth according to the criteria required by the guideline such as the extra oral time which should be very short, the time of pulp removal after replantation, and the appropriate storage medium. This set of criteria may lead to a slower progression of the phenomenon of resorption with a better prognosis over time; however, there is a high risk of complications such as external root resorption which lies in late replantation. The research results of many research-groups around the world have given us a better understanding of healing and complications. Nowadays, even teeth that are replanted after a delay can be saved. The dentist remains the key person in the case of dental trauma, namely, dental avulsion as his role is the management of the emergency situations. The objective of this case study is to present a successful management of 3 avulsed permanent incisors, replanted and remained with no complications for over a period of 3 years.

A new direction in managing avulsed teeth: stem cell-based de novo PDL regeneration

Management of avulsed teeth after replantation often leads to an unfavorable outcome. Damage to the thin and vulnerable periodontal ligament is the key reason for failure. Cell- or stem cell-based regenerative medicine has emerged in the past two decades as a promising clinical treatment modality to improve treatment outcomes. This concept has also been tested for the management of avulsed teeth in animal models. This review focuses on the discussion of limitation of current management protocols for avulsed teeth, cell-based therapy for periodontal ligament (PDL) regeneration in small and large animals, the challenges of de novo regeneration of PDL on denuded root in the edentulous region using a mini-swine model, and establishing a prospective new clinical protocol to manage avulsed teeth based on the current progress of cell-based PDL regeneration studies.

Regenerative Endodontic Treatment of Maxillary Incisors with a History of Severe Traumatic Injury

The treatment objective for children with avulsed anterior teeth should concentrate on preserving the alveolar bone volume and contour. Posttraumatic external inflammatory root resorption (EIRR) is also a high-risk complication often observed in children. Regenerative endodontic procedure (REP) has been considered a successful treatment to arrest EIRR, especially in posttraumatic cases. This case report presents clinical outcomes of REP in two teeth of an 8-year-old systemically healthy patient with a history of severe dentoalveolar traumatic injury, one with a history of avulsion, and the other with an EIRR. The treatment consisted of REP on both teeth #8 and #9. The results showed some evidence of maturation in the apical third of tooth #9 and resolution of signs and symptoms on tooth #8.

Management of Inflammatory Root Resorption of Maxillary Central Incisors following Traumatic Avulsion

Background

Avulsion is among the most severe types of dental trauma, which often occurs at young ages and can compromise the long-term prognosis of the traumatized tooth. Case Report. Herein, we report replantation of two avulsed teeth. Our patient was an 11-year-old boy with two avulsed maxillary central incisors due to a bicycle fall 2 months earlier. The patient was referred to us after rigid splinting of his teeth by a surgeon. Long-term calcium hydroxide (CH) therapy was performed for the patient, and after healing of periodontal ligament (PDL), apexification was performed for both teeth followed by root canal therapy. During the 2-year follow-up, both teeth were functional and had no radiographic or clinical evidence of resorption or ankylosis.

Conclusion

The reported case highlights the favorably high tissue healing potential following severe dental trauma, given that appropriate treatment is performed. Correct endodontic management can guarantee the long-term prognosis of teeth following severe dental trauma.

Biomechanical Analysis of a Custom-Made Mouthguard Reinforced With Different Elastic Modulus Laminates During a Simulated Maxillofacial Trauma

Background/Aims

There is a lack of data regarding the influence of different laminates for mouthguard reinforcement in the mechanical response during an impact in the orofacial region. The aim of this study was to verify the influence of the laminate framework on the stresses and strains of the anterior teeth and displacement of ethylene-vinyl acetate (EVA) custom-made mouthguards during a simulated impact. The null hypotheses was that the different laminates reinforcement would present the similar effect in maxillary structures, regardless the elastic modulus.

Methods

A finite element model of human maxillary central incisors with an antagonist contact was used. A linear quasi-static analysis was used to simulate the force exerted during an impact. A total of 5 different layers were simulated inside the mouthguard at the labial portion according to the Elastic Modulus 1 MPa (Extremely flexible), 9 GPa (Low modulus reinforcement), 18 GPa (Without reinforcement), 50 GPa (Flexible alloy), 100 GPa (Titanium alloy) and 200 GPa (Hard material). The results were evaluated by means of Maximum Principal Stress (in the tooth and bone), Microstrain (periodontal ligament) and Displacement (mouthguard) criteria.

Results

The elastic modulus of the material inside the MG influenced the stress distribution on the enamel buccal face. However, it did not affect the bone tissue stress, periodontal ligament strain or root dentin tissue stress. Conclusion: The use of reinforcement inside the custom-made mouthguard can modify the stress generated in the enamel buccal surface without improvement to the root dentin, periodontal ligament or bone tissue.

Deferoxamine Reduces Inflammation and Osteoclastogenesis in Avulsed Teeth

Replacement and inflammatory resorption are serious complications associated with the delayed replantation of avulsed teeth. In this study, we aimed to assess whether deferoxamine (DFO) can suppress inflammation and osteoclastogenesis in vitro and attenuate inflammation and bone resorption in a replanted rat tooth model. Cell viability and inflammation were evaluated in RAW264.7 cells. Osteoclastogenesis was confirmed by tartrate-resistant acid phosphatase staining, reactive oxygen species (ROS) measurement, and quantitative reverse transcriptase–polymerase chain reaction in teeth exposed to different concentrations of DFO. In vivo, molars of 31 six-week-old male Sprague–Dawley rats were extracted and stored in saline (n = 10) or DFO solution (n = 21) before replantation. Micro-computed tomography (micro-CT) imaging and histological analysis were performed to evaluate inflammation and root and alveolar bone resorption. DFO downregulated the genes related to inflammation and osteoclastogenesis. DFO also reduced ROS production and regulated specific pathways. Furthermore, the results of the micro-CT and histological analyses provided evidence of the decrease in inflammation and hard tissue resorption in the DFO group. Overall, these results suggest that DFO reduces inflammation and osteoclastogenesis in a tooth replantation model, and thus, it has to be further investigated as a root surface treatment option for an avulsed tooth.

Management and Follow-Up of Complicated Crown Fractures with Intrusive Luxation of Maxillary Incisors in an 8-Year-Old Boy

Intrusive luxation is a severe form of dental injury which causes damage to the pulp and supporting structures of a tooth because of its dislocation into the alveolar process. This paper shows the case of the reeruption of maxillary incisors accompanied by complicated crown fractures after 3 months. An 8-year-old boy patient was referred to the Department of Pedodontic Dentistry of Tehran University of Medical Science, Tehran, Iran, 18 hours after a fall at school. Clinical and radiographic examinations revealed intrusive luxation of both incisors with complicated crown fractures. Cervical pulpotomy is the treatment of choice for traumatized immature intruded teeth with pulp exposure. Two months later, the right central incisor teeth reerupted to a normal position and the final aesthetic restorations were done. The left central incisor was spontaneously repositioned with external root resorption, and the team decided to use interim medication (calcium hydroxide) in the root canal for stopping the process of resorption, and by the 9-month follow-up, the process of resorption had been stopped. An MTA plug was placed into the canal, and the final esthetic restorations were done.

Cell-Based Therapy for Tooth Replantation Following Avulsion: A Systematic Review

The management of avulsed teeth undergoing delayed replantation remains a clinical challenge as there are currently no effective interventions that can improve periodontal healing and prevent replacement root resorption. While several preclinical studies have reported varied success using cell-based tissue engineering to improve periodontal healing, a consensus is required before further clinical translation. Therefore, this systematic review seeks to evaluate the efficacy of cell-based therapy in promoting periodontal healing following delayed replantation in animal models. MEDLINE (PubMed) and Embase were searched on September 27, 2020. Ten studies involving rodent and dog models met the inclusion criteria. Cell sources included gingiva, periodontal ligament (PDL), bone marrow, and adipose tissues. Generally, cell-based therapy had increased the proportion of root surfaces displaying periodontal healing and concomitantly reduced the proportion presenting with replacement root resorption and ankylosis. The best outcomes were observed following treatment with PDL-derived cells of various potency. Future preclinical studies will benefit from adopting measures to minimize bias during the conduct of animal experiments and the standardization of the outcome measures reporting. This will facilitate future reviews with possible pooling of results in the form of meta-analyses, allowing a consensus to be obtained from the literature. In addition, further research will be required to shed light on the implications of using allogeneic cells as well as the optimization of cell delivery protocols. The findings of this systematic review demonstrated the therapeutic potential of certain cell-based therapies in promoting periodontal healing following delayed replantation, thus highlighting their prospective clinical benefits and translational value.

Pathophysiological mechanisms of root resorption after dental trauma: a systematic scoping review

Background

The objective of this scoping review was to systematically explore the current knowledge of cellular and molecular processes that drive and control trauma-associated root resorption, to identify research gaps and to provide a basis for improved prevention and therapy.

Methods

Four major bibliographic databases were searched according to the research question up to February 2021 and supplemented manually. Reports on physiologic, histologic, anatomic and clinical aspects of root resorption following dental trauma were included. Duplicates were removed, the collected material was screened by title/abstract and assessed for eligibility based on the full text. Relevant aspects were extracted, organized and summarized.

Results

846 papers were identified as relevant for a qualitative summary. Consideration of pathophysiological mechanisms concerning trauma-related root resorption in the literature is sparse. Whereas some forms of resorption have been explored thoroughly, the etiology of others, particularly invasive cervical resorption, is still under debate, resulting in inadequate diagnostics and heterogeneous clinical recommendations. Effective therapies for progressive replacement resorptions have not been established. Whereas the discovery of the RANKL/RANK/OPG system is essential to our understanding of resorptive processes, many questions regarding the functional regulation of osteo-/odontoclasts remain unanswered.

Conclusions

This scoping review provides an overview of existing evidence, but also identifies knowledge gaps that need to be addressed by continued laboratory and clinical research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01510-6.

Geomorphologic study of human tooth root surfaces following simulated avulsion by scanning electron microscopy

BACKGROUND/AIMS

Tooth avulsion is the most severe traumatic tooth injury. Immediate replantation after avulsion provides the highest success rate, whereas delayed replantation with dehydration for >1 h always results in ankylosis, replacement resorption, and eventual tooth loss. The aim of this study was to investigate the geomorphologic change of ultrastructure on tooth root surfaces due to dehydration.

MATERIAL AND METHODS

Twenty-four sound human premolars and fully developed third molars without periodontitis were selected for the experiment. Roots were separated into 6-7 pieces with an intact root surface area (3 × 3 mm² ) and then divided into the following groups: fresh group, prolonged dehydration groups (air drying for 1, 2, 4, 12, or 24 h), and dehydrated teeth (air drying for 2 h) treated with acid (Tris-HCl buffer or citric acid buffer). More than six pieces of root from each group were subjected to scanning electron microscopy (SEM) observation. Captured images were exported to ImageJ software to quantitatively analyze the areas covered with fibers. Statistical significance was determined by comparing the means of the different groups using t-testing or one-way analysis of variance followed by post hoc testing.

RESULTS

Fibrous "vegetation" covering the cementum was observed on the fresh root surface by SEM. This was destroyed by dehydration (>1 h), resulting in a root surface resembling the "Gobi Desert." The difference was statistically significant (p < .001). Root surface deteriorated by dehydration could be recovered by the re-use of the fibers embedded in the cementum as acid demineralization of the outer layer of cementum exposed the embedded fibers to simulate the geomorphology of fresh root surface.

CONCLUSIONS

Dehydrated teeth had deteriorated geomorphology of the root surface, which could be reversed by the re-use of the fibers embedded in the cementum using citric acid. Direct evidence from SEM gives new insights into the replantation of dehydrated avulsed teeth.

Severe Case of Delayed Replantation of Avulsed Permanent Central Incisor: A Case Report with Four-Year Follow-Up

Avulsion is one of the most serious dental traumatic injuries with a reserved prognosis. This case report describes multiple trauma lesions in permanent central incisors of an eight-year-old girl and a four-year follow-up. The right upper incisor suffered avulsion, remained 16 h extraorally, and was replanted after extraoral endodontic therapy. The left maxillary central incisor suffered a noncomplicated crown fracture with concomitant subluxation. The present case adds to the literature a rare occurrence of success in a severe case with poor prognosis. For this reason, the International Association for Dental Traumatology (IADT) guidelines should be followed and, even in extreme situations, replantation should always be considered.