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

Feasibility and Outcomes of Cell-based Regenerative Endodontic Therapy in Postautogenous Transplantation of a Mature Tooth: A Case Report

Autogenous tooth transplantation (ATT) offers advantages; however, success rates depend on factors like socket formation, donor tooth manipulation, and endodontic treatment. Root canal treatment in a mature post-ATT tooth remains challenging. Cell-based regenerative endodontic therapy (RET) shows promise for regenerating the pulp-dentin complex in mature teeth. However, its application in a post-ATT tooth is unexplored. This case report demonstrates the feasibility and outcomes of cell-based RET in a post-ATT tooth. A 37-year-old male underwent ATT for a missing maxillary left first molar. The maxillary right third molar served as the donor tooth and transplanted with surgical guides. Root canal treatment began two weeks after ATT, confirming no detectable residual bacteria and fungi after 11 weeks. Dental pulp stem cells isolated from the maxillary left third molar were transplanted into the root canal 17 weeks after ATT. The ATT tooth responded positively to the electric pulp test after 1 week. Most of the periodontal ligament of the donor tooth was absent, and the ATT tooth initially showed ankylosis-like signs but regained normal mobility after 28 weeks after RET. Cone-beam computed tomography imaging showed successful outcomes with the presence of the periodontal ligament space and lamina dura, and without root resorption and ankylosis after 52 weeks. Magnetic resonance imaging revealed signal intensity of the regenerated tissue comparable to normal pulp after 60 weeks. This case report suggests the effectiveness of dental pulp stem cells in regenerating dental pulp and periodontal ligament, potentially preventing root resorption and ankylosis in the post-ATT tooth.

Risk of ankylosis of avulsed teeth immediately replanted or stored under favorable storage conditions before replantation: A long-term clinical study

BACKGROUND/AIM

There are few long-term clinical follow-up studies on human teeth replanted immediately or after storage in a suitable storage medium prior to replantation. This study aimed to assess the risk of ankylosis in avulsed human teeth replanted immediately or after storage in physiological media for a short time.

MATERIAL

Data from 116 patients with 145 replanted avulsed permanent teeth were selected from a comprehensive dental trauma database in Copenhagen University Hospital. The following teeth were selected: Group 1 comprised 36 teeth replanted immediately (dry time <6 min; wet time <6 min). Group 2 comprised 61 teeth replanted after physiologic storage media (saliva and saline) (dry time <6 min; wet time >5 min; wet time ranged from 7 to 170 min, and mean wet time was 59 min). Group 3 (control) included 48 teeth replanted after dry storage (dry time > 60 min).

METHOD

Clinical and radiographic registrations were carried out according to a standardized protocol; follow-up ranged from 7 months to 23 years. Ankylosis was diagnosed by percussion test and radiographs and related to the conditions prior to replantation and stage of root development.

RESULTS

The overall risk of ankylosis was 17.2% [95% CI: 4.61; 29.79] for immediately replanted teeth, 55.3% [95% CI: 42.54; 68.00] for teeth stored in physiologic media before replantation, and 85.7% [95% CI: 75.70; 95.73] for teeth stored dry more than 1 h. Mature teeth showed a significantly higher risk of ankylosis than immature teeth.

CONCLUSION

This clinical long-term study has verified earlier experimental studies showing that immediate reimplantation has the lowest risk of ankylosis. Physiologic storage media are good alternatives that also reduce the risk of ankylosis compared to dry storage, where ankylosis is more likely although not always seen. Mature teeth are significantly more likely to develop ankylosis.

Histological effects of photobiomodulation on delayed tooth replantation: a systematic review

This systematic review evaluated preclinical studies to assess whether PBM has a more favorable histological response than other treatments used before delayed replantation of avulsed teeth. This review followed the PRISMA checklist and was registered in PROSPERO. MEDLINE (PubMed), Embase, Scopus and Web of Science were searched from their inception to July 14, 2022. Data were independently extracted by two reviewers. Data were collected about species, number of animals, number and type of teeth, groups evaluated, extra-alveolar time, parameters for PBM and other study groups, presence and characteristics of containment, observation time points, evaluation methods, characteristics evaluated, and significant results. The ARRIVE and SYRCLE tools were used to assess the methodological quality and risk of bias (RoB) of the studies. After screening, six studies were included in the review synthesis. Three of the four studies that evaluated root resorption as an outcome found that PBM decreases its occurrence after delayed tooth replantation. A meta-analysis was not conducted because some data were missing in the included studies. Half of the studies evaluating ankylosis found an increase in its occurrence after PBM. Two studies evaluated inflammatory responses and found a reduction of inflammation after PBM. In general, studies had high methodological heterogeneity, intermediate reporting quality and high RoB. Despite the methodological quality and RoB limitations of the studies, the histological responses after delayed tooth replantation were more favourable in the PBM groups. Preclinical studies supported by guidelines should define laser parameters for future clinical studies.

The effect of fibroblast growth factor-2 on the outcomes of tooth replantation: A systematic review of animal studies

Background/Aim: The ideal treatment of tooth avulsion is replantation. However, replanting teeth may lead to root resorption. Fibroblast growth factor-2 (FGF-2) is a cytokine that plays an important role in wound repair and tissue regeneration. Recently, FGF-2 has been studied a potential regenerative agent to prevent root resorption and ankylosis. The aim of this review is to analyze and summarize the currently available literature focusing on using FGF-2 based regenerative modalities to improve the outcomes of tooth replantation. Materials and Methods: An electronic search was conducted via PubMed/Medline, Google Scholar and ISI Web of Knowledge, using the Medical Subject Headings (MeSH) terms "Basic fibroblast growth factor," "Fibroblast growth factor-2," "tooth replantation," and "replantation" for studies published between January 2001 and June 2021. Data was extracted and quality assessment was carried using the ARRIVE guidelines. Results: Nine animal studies were included in this review. In six studies, FGF-2 had a favorable effect on the tissue regeneration around roots of replanted teeth when compared to other treatment groups. However, quality assessment of the studies revealed many sources of bias and deficiencies in the studies. Conclusions: Within the limitations of this study, it may be concluded that FGF-2 may improve the outcomes of delayed replantation of avulsed teeth. However, more long-term animal studies, with improved experimental designs, and clinical trials are required to determine the clinical potential of the growth factor in improving the outcomes of delayed tooth replantation.

Bone formation ability of Gli1+ cells in the periodontal ligament after tooth extraction

During the process of socket healing after tooth extraction, osteoblasts appear in the tooth socket and form alveolar bone; however, the source of these osteoblasts is still uncertain. Recently, it has been demonstrated that cells expressing Gli1, a downstream factor of sonic hedgehog signaling, exhibit stem cell properties in the periodontal ligament (PDL). Therefore, in the present study, the differentiation ability of Gli1⁺-PDL cells after tooth extraction was analyzed using Gli1-Cre^ERT2/ROSA26-loxP-stop-loxP-tdTomato (iGli1/Tomato) mice. After the final administration of tamoxifen to iGli1/Tomato mice, Gli1/Tomato⁺ cells were rarely detected in the PDL. One day after the tooth extraction, although inflammatory cells appeared in the tooth socket, Periostin⁺ PDL-like tissues having a few Gli1/Tomato⁺ cells remained near the alveolar bone. Three days after the extraction, the number of Gli1/Tomato⁺ cells increased as evidenced by numerous PCNA⁺ cells in the socket. Some of these Gli1/Tomato⁺ cells expressed BMP4 and Phosphorylated (P)-Smad1/5/8. After seven days, the Osteopontin⁺ bone matrix was formed in the tooth socket apart from the alveolar bone. Many Gli1/Tomato⁺ osteoblasts that were positive for Runx2⁺ were arranged on the surface of the newly formed bone matrix. In the absence of Gli1⁺-PDL cells in Gli1-Cre^ERT2/Rosa26-loxP-stop-loxP-tdDTA (iGli1/DTA) mice, the amount of newly formed bone matrix was significantly reduced in the tooth socket. Therefore, these results collectively suggest that Gli1⁺-PDL cells differentiate into osteoblasts to form the bone matrix in the tooth socket; thus, this differentiation might be regulated, at least in part, by bone morphogenetic protein (BMP) signaling.

Retrospective analysis of survival of avulsed and replanted permanent teeth according to 2012 or 2020 IADT Guidelines

This study aimed to compare the survival of replanted teeth that followed the 2012 or the 2020 International Association of Dental Traumatology (IADT) guidelines. Sixty-two permanent replanted teeth were retrospectively assessed (IADT 2012, n = 45; IADT 2020, n = 17). Five years after replantation (from January 2017 to December 2021), clinical and radiographic examinations were performed. A significance level of 95% was considered to evaluate the outcomes. Thirty-one teeth (50.0%) remained in their sockets and 31 (50.0%) were lost due to external root resorption. Of the 25 (40.3%) teeth replanted within one hour, 16 (64.0%) remained in their sockets, and 9 (36.0%) were lost. Twenty-two (71.0%) of all 31 lost teeth had an extra-alveolar time of more than one hour. Twelve teeth remained in their sockets without resorption: 8 (66.7%) were replanted within one hour, 2 (16.7%) followed the 2012 IADT, and 2 (16.7%) the 2020 IADT guidelines for late replantation. There was a significant difference (p <0.05) in the extra-alveolar time (< one hour), but without difference between the guidelines in late replantation (p > 0.05). Replanted teeth following both, 2012 or 2020 IADT guidelines, have similar clinical outcomes. The extra-alveolar time of less than one hour was demonstrated to be important to keep the permanent tooth in its socket.

Effects of erythropoietin on osteoblast in the tooth extraction socket in mice periodontitis model

Periodontitis is an excessive inflammatory event in tooth-supporting tissues and can cause tooth loss. We used erythropoietin (EPO), which has been reported to play an important role in bone healing and modulation of angiogenesis, as a therapeutic agent in vivo and in vitro experimental models to analyze its effect on periodontitis. First, EPO was applied to in vitro MC3T3-E1 cells and human periodontal ligament fibroblast (hPDLF) cells to examine its function in altered cellular events and gene expression patterns. In vitro cultivation of MC3T3-E1 and hPDLF cells with 10 IU/ml EPO at 24 and 48 h showed an obvious increase in cell proliferation. Interestingly, EPO treatment altered the expression of osteogenesis-related molecules, including alkaline phosphatase (ALP), bone morphogenetic protein-2 (BMP-2), and osteocalcin (OC) in MC3T3-E1 cells but not in hPDLF cells. In particular, MC3T3-E1 cells showed increased expression of ALP, BMP-2, and OC on day 5, while hPDLF cells showed increased expression of BMP-2, and OC on day 14. Based on the in vitro examination, we evaluated the effect of EPO on bone formation using an experimentally-induced animal periodontitis model. After the induction of periodontitis in the maxillary left second M, 10 IU/ml of EPO was locally applied to the extraction tooth sockets. Histomorphological examination using Masson’s trichrome (MTC) staining showed facilitated bone formation in the EPO-treated groups after 14 days. Similarly, stronger positive reactions against vascular endothelial growth factor (VEGF), cluster of differentiation 31 (CD31), runt-related transcription factor 2 (RUNX2), and osteocalcin (OC) were detected in the EPO-treated group compared to the control. Meanwhile, myeloperoxidase, an inflammatory marker, was decreased in the EPO-treated group on days 1 and 5. Overall, EPO facilitates bone healing and regeneration through altered signaling regulation and modulation of inflammation in the osteoblast cell lineage and to a lesser extent in hPDLF cells.

Fibrillin protein, a candidate for creating a suitable scaffold in PDL regeneration while avoiding ankylosis

The tooth is stabilized by fiber-rich tissue called the periodontal ligament (PDL). The narrow space of the PDL does not calcify in the physiological state even thought it exists between two calcified tissues, namely, the cementum of the root and alveolar bone. Two situations that require PDL regeneration are periodontitis and dental trauma. Periodontitis induces the loss of PDL and alveolar bone due to inflammation related to infection. Conversely, in PDLs damaged by dental trauma, accelerating bone formation as an overreaction of the healing process is induced, thereby inducing dentoalveolar ankylosis at the tooth root surface. PDL regeneration following dental trauma must therefore be considered separately from periodontitis. Therefore, PDL regeneration in dental trauma must be considered separately from periodontitis. This review focuses on the components involved in avoiding dentoalveolar ankylosis, including oxytalan fibers, aggregated microfibrils, epithelial cell rests of Malassez (ERM), and TGF-β signaling. During root development, oxytalan fibers produced by PDL cells work in collaboration with the epithelial components in the PDL (e.g., Hertwig's root sheath [HERS] and ERM). We herein describe the functions of oxytalan fibers, ERM, and TGF-β signals which are involved in the avoidance of bone formation.

The Impact of Autologous Platelet Concentrates on the Periapical Tissues and Root Development of Replanted Teeth: A Systematic Review

Introduction: In many cases, the replanted teeth may undergo resorption or ankyloses. Recent studies show that autologous platelet concentrates (APCs) may improve the outcomes of tooth replantation. The aim of this systematic review was to summarize and critically appraise the currently available literature on the use of APCs before tooth replantation. Methodology: An electronic search was conducted on the following research databases: PubMed/MEDLINE, ISI Web of Science, EMBASE and Scopus. The following medical subject heading (MeSH) keywords used were: ((tooth replantation) OR (replanted tooth) OR (teeth replantation) OR (replanted teeth)) AND ((autologous platelet concentrate) OR (platelet-rich plasma) OR (platelet-rich fibrin) OR (autologous platelet)). The studies’ data was extracted, and the research’ quality was rated using the CARE and ARRIVE protocols. Results: Ten case reports and three animal studies, one cell study and one study, which included both animal and in vitro experiments, were included in this review. In majority of the studies, APCs improved the outcomes of tooth replantation. However, there were various sources of bias in the most of the research, which may have influenced the results. Conclusions: Although majority of the studies indicate that APCs may improve outcomes of tooth replantation, majority of the studies contained numerous sources of bias. Additionally, the sample size of the included subjects is inadequate to predict the clinical efficacy of APCs in management of replanted teeth. Large-scale, multi-center and long-term studies are required to ascertain the efficacy of APCs in improve the outcomes of tooth replantation.

Effect of tetracyclines on pulpal and periodontal healing after tooth replantation: a systematic review of human and animal studies

Background

Pulpal and periodontal healing are two main concerns of delayed replantation of avulsed teeth. The objective of this review was to evaluate the effectiveness of topical and systemic application of tetracyclines on pulpal and periodontal healing after tooth replantation.

Methods

A comprehensive electronic search was conducted in six databases. This systematic review was carried out according to Cochrane Handbook and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

Results

After exclusion of 246 irrelevant papers, 14 animal studies and one human study were included in this review. The human study showed that avulsed permanent teeth treated with doxycycline did not show a better clinical outcome for pulp and periodontal healing compared with treatment with normal saline. As for animal studies, significant more pulpal healing was observed in immature teeth treated with topical doxycycline in two researches, while another one study showed that there is no difference between teeth treated with normal saline and teeth treated with doxycycline. Systemic doxycycline exerted no significant effect on pulpal revascularization illustrated by one research. Only one out of four articles illustrated the positive effect of systemic tetracyclines on periodontal healing. One paper reported that intracanal application of demeclocycline promoted favorable periodontal healing. Two articles showed topical doxycycline contributed to favorable periodontal healing, while five studies showed no significant effect of topical tetracyclines on periodontal healing.

Conclusions

As a result of data heterogeneity and limitations of the studies, the effect of topical or systemic application of tetracyclines on pulpal and periodontal healing is inconclusive. More studies are required to get more clinically significant conclusions.

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.

The impact of platelet-rich fibrin (PRF) on delayed tooth replantation: A preliminary animal study

The aim of this study was to evaluate the effect of platelet-rich fibrin (PRF) placed in delayed replantation of mature extracted teeth. Sixteen intentionally extracted teeth in two mature beagle dogs were selected. In one quadrant of each jaw, the extraction sockets were filled with PRF prior to replantation, and the other quadrant served as control without PRF. All extracted teeth underwent endodontic treatment and dried for 60 min. Thereafter, they were replanted with a flexible splint. After 8 weeks, the animals were euthanised, and the histological sections examined. Less inflammatory root resorption was noted in the PRF group compared to the control (P = 0.031). However, there was no significant difference between the two groups with regard to new bone formation, inflammatory status, connective tissue healing and replacement resorption (P > 0.05). Using PRF in the extracted socket before delayed replantation did not provide any significant benefit other than reduced inflammatory root resorption.

Permanent tooth avulsion in children and adults: Therapeutic options for longer survival

Introduction: Permanent tooth avulsions (traumatic extraction; total luxation) are one ofthe most severe permanent tooth injuries and can occur as single injuries or associated with other dental injuries or injuries to the face and jaws region. They are defined as the luxation of teeth from the alveoli with complete rupture of periodontal fibres, or with one part attached to the rootcementum and the other to the alveolar bone, thus compromising the dental pulp, root cementum,and alveolar bone. The high prevalence and numerous negative consequences on the stomatognathic systems they have suggest permanent tooth avulsions should be regarded as an important public health problem. The aim: is to point out the therapeutic possibilities of permanent tooth avulsion that can ensure their longer survival in the oral cavity. Conclusion: The treatment strategy for avulsed permanent teeth is always based on limiting root canal infection and periradicular inflammation, shifting the balance from unfavourable (replacement resorption) to favourable (periodontal) healing. The success of therapy and periodontal healing depend on the duration and conditions of extraoral tooth preservation, the degree of damage to the periodontal ligament, and the condition of the pulp.

[Decoronation management of the replacement resorption after delayed replantation of avulsed teeth-case report with 4-year follow-up]

Replacement resorption is the most frequent complication after delayed replantation of avulsed teeth. The resorption can interfere with the development of the alveolar ridge and lead to tilt of the adjacent teeth in growing patients. However, there is no means of arresting or reversing the process. Recently decoronation is recommended by International Assocaition of Dental Traumatology as the optimal choice to manage it. This paper demonstrates the procedure and effectiveness of the decoronation by literature review and a case report with 4-year follow-up.

Efficacy of Hank's balanced salt solution compared to other solutions in the preservation of the periodontal ligament. A systematic review and meta-analysis

This systematic review and meta-analysis (MA) aimed to verify the capacity of different storage media to preserve viability of periodontal ligament cells in comparison to Hank’s Balanced Salt Solution. The searches, selection process, data extraction and Risk of Bias control were conducted according to Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Five MA were conducted to compare the cell viability between milk versus Hank's balanced salt solution (HBSS) in a dichotomous (1) or continuous (2) data model; tap water versus HBSS (3); medicinal herbals versus HBSS (4); and saline solution versus HBSS (5). 693 potentially studies were identified, with 18 studies included in the qualitative and 8 studies included in the quantitative analysis. Most of the articles presented a low risk of bias. HBSS medium showed a superior ratio of cell viability compared to tap water (RR 0.26; 95% CI [0.21, 0.32]; p < 0.00001; I2 = 96%) and saline solution (RR 0.76; 95% CI [0.69, 0.84]; p < 0.0001; I2 = 99%). Herbal medicines showed a similar ratio of cell viability when compared to HBSS (RR 0.97; 95% CI [0.94, 1.00]; p = 0.08; I² = 50%). Mixed results were observed between milk and HBSS: a superior ratio of HBSS was observed in an overall evaluation (RR 0.26; 95% CI [0.21, 0.32]; p < 0.00001; I² = 96%), and a similar ratio was achieved when periodontal ligament (PDL) cells were removed prior to immersion in the solution (RR 0.94; 95% CI [0.87, 1.01]; p = 0.10; I2 = 0%) or rinsed in tap water or maintained in open air prior to immersion (RR 0.63; 95% CI [0.35, 1.12]; p = 0.11; I2 = not applicable). This systematic review and MA suggests that milk and herbal medicines could represent an alternative to HBSS. However, more studies are necessary to obtain a reliable conclusion.

The effect of cathepsin K inhibitor surface treatment on delayed tooth replantation in dogs

BACKGROUND/AIM

Continuous research efforts have been focusing on promoting healing of delayed replantation of avulsed teeth. The aim of this in vivo study was to assess the effect of cathepsin K inhibitor surface treatment on delayed tooth replantation.

MATERIALS AND METHODS

Thirty-four premolar roots of 4 beagle dogs were extracted, and conventional root canal treatment was performed. The canals were filled with gutta-percha and cement. All extracted teeth were air-dried for 1 hour. Teeth were divided into 2 groups according to the root surface treatment prior to replantation: control (n = 13) and cathepsin K inhibitor (n = 21). Treated teeth were replanted in their original sockets and stabilized with a resin-wire splint for 1 week. After 12 weeks, the dogs were euthanized and micro-computed tomography was performed. Tissues were then further processed as resin-embedded specimens stained with hematoxylin and eosin. In each evaluation, data were analyzed using the Mann-Whitney U test (P < .05).

RESULTS

In the micro-computed tomography evaluation, inflammation scores of both groups were not statistically different (P > .05). In the histological evaluation, the mean proportions of inflammatory resorption and replacement resorption in the control group were similar to those in the cathepsin K inhibitor group (P > .05).

CONCLUSIONS

Cathepsin K inhibitor did not demonstrate significant inhibitory effects on root resorption after delayed replantation in vivo.

The effects of three modified Hank's balanced salt solutions on root resorption of late replanted teeth: A pilot study

PURPOSE

The purpose of this study was to evaluate the effects of replanted rats' teeth that had been soaked in one of three modified Hank's balanced salt solutions (HBSSs) before replantation and after extended extra-oral dry time.

MATERIALS AND METHODS

Maxillary right incisors were extracted from 55 Wistar rats and kept dry for 30 or 60 min (n = 5 each). Afterwards, the pulp was extirpated and both the papilla and enamel organ were removed with a scalpel. Each group of teeth was soaked in one of three modified HBSSs or HBSS alone. After 30 min of immersion in solutions, the root canals were dried and filled with calcium hydroxide paste, and the teeth were replanted. After 8 weeks, animals were euthanized; then, specimens were processed as 5 μm-thick serial sections for histological examination and morphometric assessments.

RESULTS

The percentages of root resorption for the groups were found to be in the following order: HBSS3 (the bFGF group) > the HBSS only group > HBSS2 (the GSH group) > no soaking (the positive control group) > HBSS1 (the ALN group) for 30 min and the positive control group > the HBSS only group > HBSS2 > HBSS3 > HBSS1 for 60 min. The lowest incidence of resorption was observed in immediately replanted teeth (negative control).

CONCLUSIONS

The findings of this study suggest that soaking for 30 min in HBSS containing 1 mM alendronate can significantly inhibit root resorption for avulsed teeth that have been dried for 60 min.

Effect of EMD on the orthodontically induced root resorption repair process in rats

BACKGROUND

While different levels of root resorption may occur in orthodontic treatment, several preventive approaches have been reported. Nevertheless, little is known about the effect of enamel matrix derivative (EMD) on root repair during orthodontic tooth movement.

OBJECTIVE

To evaluate the effect of EMD on root resorption repair following the application of orthodontic force.

MATERIALS AND METHODS

A force of 100 g was exerted for 14 days on the left maxillary first molars of twenty 10-week-old Sprague-Dawley rats divided into the EMD and control groups (n = 10 per group). In the EMD group, repeatedly injection of Emdogain® was administered after the appliance was removed, while phosphate-buffered saline was administered in the control group. In vivo microcomputed tomography (CT), haematoxylin and eosin (H&E) staining, and immunohistochemistry were then used to evaluate the effect of EMD on the process of root repair.

RESULTS

In the EMD group, the observed decrease in root resorption crater volume and increase in both the bone volume fraction and trabecular thickness were significantly greater than those in the control group. H&E staining showed that the periodontal fibres were relatively regular in arrangement and that the surface of the cementum was smooth in the EMD group. Immunohistochemical analysis showed higher bone morphogenetic protein 2 (BMP-2) and bone sialoprotein (BSP) expression levels in the EMD group than in the control group. In addition, the osteoprotegerin (OPG) and receptor activator of NF-κB ligand (RANKL) expression levels were similar in both groups.

CONCLUSION

EMD enhanced the repair process following orthodontically induced root resorption in rats.

Analysis of the association of clinical factors and IL4 gene polymorphisms with root resorption in avulsed teeth after 1 year of replantation

AIM

To investigate the association of clinical variables and polymorphisms (tag SNPs) in the interleukin 4 (IL4) gene, with the prognosis of avulsed and replanted teeth.

METHODOLOGY

Ninety-four patients who suffered avulsion and had their teeth replanted and endodontically treated were included. Periapical radiographs were obtained soon after tooth replantation and after 1 year. For genotypic IL4 gene analysis, the DNA from oral mucosa cells was collected, and polymorphisms were investigated by real-time PCR. Univariate and multivariate analyses were performed to verify the association of clinical and genetic variables and the outcome of the replanted teeth (P < 0.05).

RESULTS

After multivariate analysis, extra-alveolar time longer than 1 h was significantly associated with external root resorption. No significant association was observed between IL4 gene polymorphisms and root resorption.

CONCLUSION

No association between root resorption and IL4 gene polymorphisms was observed. An extra-alveolar time of more than 1 h was associated with a susceptibility for external root resorption. Replanting the tooth in its socket immediately is the most important factor to maintain a healthy root surface.

Effect of bisphosphonates on root resorption after tooth replantation - a systematic review

BACKGROUND/AIM

Replantation of avulsed teeth may lead to root resorption. Bisphosphonates (BPs), a class of drugs of used to treat resorptive diseases of the bone such as osteoporosis and Paget's disease, have been observed to exert an antiresorptive effect on periodontal bone as well. The antiresorptive properties of BPs could prove them useful in preventing root resorption of replanted avulsed teeth. The aim of this systematic review was to analyze and summarize the currently available literature concerning the use of BPs in preventing root resorption of avulsed teeth.

MATERIALS AND METHODS

PubMed/MEDLINE, Google Scholar, ISI Web of Knowledge, and Embase databases were searched using keywords 'bisphosphonate', 'replantation', and 'tooth'. Quality assessment of each study was carried out. In addition, general characteristics and outcomes of each study were summarized.

RESULTS

After exclusion of 116 irrelevant articles, 10 animal studies were included in this review. The majority of the studies suggest that surface application of zoledronate or alendronate reduces root resorption of replanted teeth in animal models. Surface treatment with etidronate had no significant effect on root resorption, and intracanal etidronate accelerated resorption.

CONCLUSION

Surface application of zoledronate and alendronate reduces root resorption of replanted teeth in animal models. However, the efficacy of intracanal usage of BPs is still debatable.

Effects of diode laser irradiation and fibroblast growth factor on periodontal healing of replanted teeth after extended extra-oral dry time

AIM

The search for effective protocols to reduce the incidence of root resorption and allow periodontal ligament repair is still challenging, given the unpredictable outcome of late tooth replantation. The aim of this study was to assess the effects of both high-power diode laser irradiation (DL) and basic fibroblast growth factor (FGF) on the periodontal healing of replanted teeth after extended extra-oral dry time.

METHODS

Maxillary incisors of 50 male rats were extracted and assigned to three experimental and two control groups (n = 10). DL: root surfaces treated with DL (810 nm, continuous mode, 1.0 W, 30 s), FGF: topical application of FGF gel to the root surface and in the alveolar wound, DL + FGF: DL and topical application of FGF gel, C+: no treatment after extraction and immediate replantation and C-: no treatment after extraction and replantation after 60 min. In the experimental groups, the specimens were kept dry for 60 min, the pulps were removed and the canals were filled with calcium hydroxide paste prior to tooth replantation. The animals were euthanized after 60 days. The specimens were processed for radiographic, histological and immunohistochemical analyses.

RESULTS

The radiographic analysis showed fewer resorptive areas in DL + FGF (P < 0.05). The histological and immunohistochemical analyses showed that the DL group had lower mean values of ankylosis, replacement and inflammatory resorption when compared to C-, not differing statistically from C+. DL + FGF produced significantly more collagen fibers (type I and type III) than C-, not differing from C+ in the case of type I fibers (P < 0.05).

CONCLUSIONS

DL, with or without FGF, reduced the occurrence of external root resorption and ankylosis. Periodontal healing was favored and some fiber reinsertion occurred only when FGF was used.

Influence of enamel matrix derivative on healing of root surfaces after bonding treatment and intentional replantation of vertically fractured roots

BACKGROUND/AIM

The objectives of this study were to histopathologically evaluate cementum regeneration on root surfaces when an enamel matrix derivative (EMD) was used to bond a vertically fractured root and to evaluate the effectiveness of EMD in inhibiting root resorption.

MATERIAL AND METHODS

A total of 40 roots from 24 maxillary premolars in beagles were used. The root was vertically fractured using a chisel and mallet. Super-Bond was then used to bond the fractured root. In the experimental group, the root surface was treated with ethylenediaminetetraacetic acid and an EMD. The control group received no treatment. The root was then replanted in its original location. Histopathological observation and measurement using image-analyzing software were carried out after 8 weeks.

RESULTS

In the experimental group, shallow resorption cavities developed on the root planed surfaces with new acellular cementum appearing over them. In the control group, no new cementum was seen on the planed surfaces, and there was connective tissue joining the roots. In some of the samples, resorption and multinucleated giant cells were seen. The experimental group showed a significantly larger volume of cementum formation (P < 0.001), and the volume of root resorption was significantly smaller (P = 0.004).

CONCLUSION

When bonding and replanting tooth roots after a vertical fracture, the application of EMD was effective in regenerating cementum on root surfaces from which periodontal ligament had been lost in the area around the fracture line and in reducing the incidence of root resorption.

In vitro studies on human periodontal ligament stem cell sheets enhanced by enamel matrix derivative

Numerous preclinical and clinical studies have focused on the periodontal regenerative functions of enamel matrix derivative (EMD), a heat-treated preparation derived from enamel matrix proteins (EMPs) of developing porcine teeth. In this study, periodontal ligament (PDL) stem cells (PDLSCs) were isolated, and the effects of EMD on the extracorporeal induction process and the characteristics of PDLSC sheets were investigated for their potential as a more effective stem-cell therapy. EMD-enhanced cell sheets could be induced by complete medium supplemented with 50 μg/mL vitamin C and 100 μg/mL EMD. The EMD-enhanced cell sheets appeared thicker and more compact than the normal PDLSC sheets, demonstrated more layers of cells (3-7 layers), secreted richer extracellular matrix (ECM), showed varying degrees of increases in mRNA expression of periodontal tissue-specific genes (COL I, POSTN), calcification-related genes (RUNX2, OPN, OCN) and a cementum tissue-specific gene (CAP), and possessed a better mineralization ability in terms of osteogenic differentiation in vitro. These EMD-enhanced cell sheets may represent a potential option for stem-cell therapy for PDL regeneration.

What is the Best Root Surface Treatment for Avulsed Teeth?

Dental avulsion is the most severe type of traumatic tooth injuries since it causes damage to several structures and results in avulsion of the tooth from its socket. Management protocols for avulsed teeth should include management of the pulp and periodontal ligament (PDL) cells in order to improve the long-term prognosis and survival of these teeth. The prognosis of the treatment as well as the survival of an avulsed tooth depends on intrinsic and extrinsic factors, such as the duration of the tooth's extra-alveolar period, replantation time, the type of storage medium, PDL status and duration of splinting. Recent research has led to the development of storage media. However, there is not yet a single solution that fulfills all requirements to be considered as the ideal medium for temporary storage of avulsed teeth, and research on this field should carry on. On the other hand in case of delayed replantation, due to the great risk of tooth loss after avulsion, different root surface treatments have been proposed to prevent and delay root resorption before replantation. For this purpose, researchers have applied some different root surface treatment modalities in delayed replantation of avulsed teeth. Several protocols have been used to maintain PDL viability; some involve fluorides, steroids, sodium alendronate, enamel matrix derivatives (EMD) and basic fibroblast growth factor (bFGF, FGF-2). Among these applications, bFGF shows promising results in the regeneration of natural tooth structures and tissues. Better understanding of mechanism of bFGF may help to improve new technologies of regeneration of tooth structures.