Clinical management of the avulsed tooth: present strategies and future directions

Development of clobetasol-loaded biodegradable nanoparticles as an endodontic intracanal medicament

AIM

The aim of current study is the development and optimization of biodegradable polymeric nanoparticles (NPs) to be used in the field of Endodontics as intracanal medication in cases of avulsed teeth with extended extra-oral time, utilizing PLGA polymers loaded with the anti-inflammatory drug clobetasol propionate (CP).

METHODOLOGY

CP-loaded nanoparticles (CP-NPs) were prepared using the solvent displacement method. CP release profile from CP-NPs was assessed for 48 h against free CP. Using extracted human teeth, the degree of infiltration inside the dentinal tubules was studied for both CP-NPs and CP. The anti-inflammatory capacity of CP-NPs was evaluated in vitro measuring their response and reaction against inflammatory cells, in particular against macrophages. The enzyme-linked immunosorbent assay (ELISA) was used to examine the cytokine release of IL-1β and TNF-α.

RESULTS

Optimized CP-NPs displayed an average size below 200 nm and a monomodal population. Additionally, spherical morphology and non-aggregation of CP-NPs were confirmed by transmission electron microscopy. Interaction studies showed that CP was encapsulated inside the NPs and no covalent bonds were formed. Moreover, CP-NPs exhibited a prolonged and steady release with only 21% of the encapsulated CP released after 48 h. Using confocal laser scanning microscopy, it was observed that CP-NPs were able to display enhanced penetration into the dentinal tubules. Neither the release of TNF-α nor IL-1β increased in CP-NPs compared to the LPS control, displaying results similar and even less than the TCP after 48 h. Moreover, IL-1β release in LPS-stimulated cells, decreased when macrophages were treated with CP-NPs.

CONCLUSIONS

In the present work, CP-NPs were prepared, optimized and characterized displaying significant increase in the degree of infiltration inside the dentinal tubules against CP and were able to significantly reduce TNF-α release. Therefore, CP-NPs constitute a promising therapy for the treatment of avulsed teeth with extended extra-oral time.

Effects of Doxycycline-Loaded NO-Releasing Nanomatrix Gel on Delayed Replanted of Rat Molar

BACKGROUND/AIM

Tooth avulsion and delayed replantation may cause inflammatory responses and root resorption of the tooth. The aim of this study is to investigate the effect of a doxycycline-loaded nitric oxide-releasing nanomatrix (DN) gel on the delayed replantation of avulsed rat teeth, with a focus on assessing the gel's potential to promote regeneration and inhibit complications associated with the replantation process.

MATERIALS AND METHODS

Twenty-four right maxillary first molars from male Sprague-Dawley rats were atraumatically extracted using sterile extraction forceps. The molars were dried for 1 h at room temperature (approximately 23 °C) and divided into four groups according to the root conditioning methods after extra-alveolar 60-min drying: Group 1, no root conditioning treatment prior to replantation; Group 2, soaking in 2% NaF solution for 5 min before replantation; Group 3, 5-min soaking in NO gel and injection of the gel into the alveolar socket; Group 4, 5-min soaking in DN gel and injection of the gel into the alveolar socket before replantation. The animals were euthanized four weeks after the operation and the specimens were evaluated histologically.

RESULTS

The use of NO gel alone showed better anti-inflammatory and periodontal effects than the control group, but it did not show a significant effect compared to the group using NaF. When using NO gel loaded with doxycycline, it showed a significant anti-inflammatory effect compared to the control group and showed a similar inhibitory effect to the group using NaF.

CONCLUSIONS

Within the limits of this study, in delayed replantation situations, the control of inflammatory resorption and replacement resorption is an important factor for achieving a better prognosis of replanted teeth. Root surface treatment with DN gel decreased root resorption after delayed replantation.

Knowledge and management of traumatic dental injuries among schoolteachers in Hungary: a cross-sectional study with educational intervention

PURPOSE

This study aimed to evaluate the knowledge of Hungarian schoolteachers in the management of dental trauma injuries (TDI) of children between the ages of 3 and 18 and to illustrate a brief educational intervention on TDI management.

METHODS

A 15-item questionnaire on dental injuries was distributed in our observational cross-sectional study to 2720 Hungarian educational institutions to explore and evaluate teachers' knowledge in January 2019. Two years later, targeted information material was made accessible regarding TDI management. In the second post-intervention phase of the study, educator knowledge was re-evaluated using the same questionnaire. Statistical analysis (Mann-Whitney and Chi-square tests) was performed using IBM SPSS Statistics 28.

RESULTS

A total of 1426 answers were collected in the initial survey. Although more than half (51.9%) of the respondents previously witnessed TDIs, 86.5% still did not perceive themselves as adequately informed regarding TDI management. Most teachers submitted appropriate responses to the indicator questions relating to the urgency of referral to dental professionals (71.8%), immediate contact with parents (79.0%) or dentists (13.0%), and the solution for avulsed teeth (81.3%). However, only every second (56.2%) educator responded correctly regarding the proper cleaning method. Following accessibility to our educational material, 622 respondents completed the post-intervention questionnaire in the second phase of the study. The percentage of appropriate responses to the five indicator questions significantly increased by 5-20.6%.

CONCLUSION

Teachers' knowledge of TDI was inadequate yet can improve with online education. Efforts among dental professionals, the media, and targeted interventions will ensure adequate knowledge while also improving children's dental health.

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.

Early revascularization activates quiescent dental pulp stem cells following tooth replantation in mice

Introduction

The intentional perforation of the pulp chamber floor before tooth replantation promotes pulpal healing by facilitating the revascularization of the pulp cavity. This study aimed to elucidate the effects of this method on the dynamics of quiescent dental pulp stem cells (DPSCs).

Methods

The right and left maxillary first molars of Crlj:CD1 mice and TetOP-histone 2B (H2B)-green fluorescent protein (GFP) mice were extracted. The left molars were immediately replanted as the control group (CG), whereas the pulp chamber floor of the right molars were perforated before the tooth was replanted as the experimental group (EG). Immunohistochemistry for Nestin and GFP, and quantitative RT-PCR for Nestin, Opn, CD11c, and Oct3/4 mRNA were performed.

Results

The rate of Nestin-positive perimeter along the pulp-dentin border in the EG tended to be higher than that of the CG at days 5 and 7 and was significantly increased between days 3 and 7. The rate of GFP-positive cells in the EG was significantly higher than that of the CG at days 5 and/or 7 in the mesial and middle coronal pulp. CD11c mRNA in the EG at day 5 was significantly higher than that of the CG and tended to be higher than that of the CG during the observation period. Oct3/4 mRNA expression in the EG was significantly higher than that of the CG at day 7.

Conclusions

The current experimental model demonstrated the promotion of the survival of DPSCs and their differentiation into odontoblast-like cells (OBLCs). Thus, the use of this model is expected to clarify the crosstalk mechanism between immune cells, including macrophages and dendritic cells, and DPSCs with regards to pulpal healing after tooth replantation. It also provides insight into the differentiation process of DPSCs into OBLCs.

Knowledge, Awareness, and Practice Regarding Management of Dental Trauma in Children among Dental Practitioners: A Cross-sectional Survey

AIM

The aim of this study was to determine the current level of knowledge and understanding about dental trauma and its management in children among dental practitioners.

MATERIALS AND METHODS

The study was conducted after obtaining the ethical clearance from the Institutional Review Board (IRB). A structured questionnaire was prepared, which comprised 20 questions and was validated by dental trauma experts. The questionnaire, which covers all aspects of traumatic dental injuries (TDIs) in both primary and permanent dentition, was distributed online to 850 dental practitioners. The questionnaire was open from January 2022 to April 2022, with a 3-month time frame to complete it. The responses were collected and statistical analysis was done using SPSS software.

RESULTS

The mean age of the participants were 22-30 years. Furthermore, 515 participants were females and 263 were males. In this survey among 784 responses, 449 dentists were trained in dental trauma and 618 participants had personal experience in managing dental trauma. All other questions about knowledge and awareness of dental trauma management received fewer correct answers.

CONCLUSION

According to the present study, dental practitioners have only mild-to-moderate knowledge and awareness about dental trauma. From the latest the International Association for Dental Traumatology guidelines, dentists need to consistently update their knowledge through dental trauma conferences, workshops, trainings, and symposiums.

CLINICAL SIGNIFICANCE

This study informs us about the existing level of dental knowledge about dental trauma, which is significantly low. This will considerably boost dental practitioners' interest in TDIs. As a result, practitioners' expertise will grow, allowing them to better care for their patients.

Regenerative endodontic therapy for external inflammatory lateral resorption following traumatic dental injuries: Evidence assessment of best practices

BACKGROUND

External inflammatory lateral resorption (EILR) following dental trauma is a severe complication that can lead to significant root loss and tooth extraction.

OBJECTIVE

The aim of this project was to review current evidence in the literature on regenerative endodontic therapy (RET) for EILR following traumatic injuries and assess the best treatment practices.

METHODS

Publications appearing in PubMed, from January 1, 2001 to January 9, 2022 were studied. Inclusion criteria were: (a) Publications in English; (b) Publications on RET and EILR; (c) Teeth subjected to dental trauma; and (d) Presence of intracanal bleeding and blood clots. Exclusion criteria were: (a) Conference proceedings; (b) Lectures; (c) Abstracts; and (d) Letters to editor; (e) Non-English publications.

RESULTS

355 publications were analysed. Nine met all inclusion criteria. In 10 (58.8%) teeth, triple antibiotic paste was used for an average of 26 days. Double antibiotic paste was used in 3 (17.6%) teeth for an average of 14 days. In 3 (17.6%) cases, calcium hydroxide (Ca(OH)₂ ) was used for 14 days and negative pressure irrigation was applied once on 1 (6%) tooth.

DISCUSSION

Using RET to treat EILR has some advantages compared to long term CA(OH)₂ dressing. RET requires shorter dressing time compared to CA(OH)₂ . This can significantly improve patient compliance. Additionally, in immature teeth, RET helps to arrest root resorption leading to continued root maturogenesis and revascularization. It is recommended that a meticulous follow-up should be conducted when RET is performed to assure early detection of treatment failure.

CONCLUSIONS

RET appears to be a good treatment modality producing biologic repair and improving prognosis in cases of EILR in post-traumatic tooth/pulp injuries. The key limitation of this study is that all publications included were either case reports or case series that usually tend to report successful outcome.

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.

Effect of Photobiomodulation on Periodontal Ligament Cells Under Inflamed and Nutrient-Deficient Conditions Simulating Damaged Cells of Avulsed Teeth: An In Vitro Study

Background: The prognosis of replanted teeth is depended on the vitality of periodontal ligament cells residual on the root surface. Photobiomodulation has photobiological effects that can promote cell vitality. The study aimed to explore the effect of photobiomodulation on the periodontal ligament cells under inflamed or starved conditions mimicking clinically damaged periodontal ligament cells of avulsed teeth and provide the adjuvant procedure for tooth replantation. Materials and methods: Normal, starved, or inflamed periodontal ligament cells were irradiated with an 808 nm laser at densities of 0, 1, 3, 5, or 10 J/cm². The cell counting kit-8 (CCK-8) assay and scratch test were applied to determine the effects on the proliferation and migration of cells. Anti-inflammatory effects were assessed according to the mRNA expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) measured by reverse-transcription polymerase chain reaction. Osteogenic capacity was evaluated by alkaline phosphatase (ALP) staining, ALP activity assay, Alizarin Red S staining, and ALP and osteocalcin (OCN) mRNA expression. Results: The CCK-8 assay and scratch test demonstrated that the 808 nm laser significantly promoted proliferation and migration of normal condition periodontal ligament cells at a density of 3 J/cm² versus 5 J/cm² under the starved and inflamed conditions. Moreover, the 808 nm laser had anti-inflammatory effects and promoted osteogenesis of periodontal ligament cells at 3 J/cm² under normal conditions, while photobiomodulation at 5 J/cm² upregulated the osteogenesis of periodontal ligament cells under starved and inflamed conditions. Conclusions: The photobiomodulation of 808 nm laser reduced inflammation and improved the proliferation, migration, and osteogenesis of normal, starved, and inflamed periodontal ligament cells. These effects required a higher energy density under starved or inflamed conditions compared with normal conditions. The photobiomodulation of 808 nm has a potential application in root surface treatment for replanted teeth.

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.

Knowledge and attitudes of emergency medicine physicians and nurses regarding emergency management of dentofacial trauma in pediatric patients

OBJECTIVES

Considering that the first visit for dentofacial trauma is generally in emergency departments, the awareness and knowledge of the emergency medicine staff regarding the treatment of dentofacial injuries is very important for the prognosis. The aim of this study was to investigate the knowledge, education, and self-confidence levels of emergency medicine physicians and nurses concerning the diagnosis and treatment of dentofacial traumatic injuries in pediatric patients.

METHODS

This questionnaire-based, cross-sectional study included emergency medicine physicians and emergency medicine nurses. The survey contained questions and three sections on participants' general data, attitudes, basic knowledge, and confidence levels in managing dentofacial trauma.

RESULTS

A total of 407 participants (250 emergency medicine physicians and 157 emergency medicine nurses) were included in this study. There was a significant difference between the groups regarding the correct answers to the questions about trauma management and emergency management of crown fractures and avulsed permanent teeth (p <0.05).

CONCLUSION

Our findings show that there is a lack of information on dentofacial trauma for emergency medicine physicians and nurses. In order to increase knowledge in this area and to improve the diagnosis and management of dentofacial trauma, interdisciplinary seminars, case discussions, and continuing education programs should be held for emergency medicine staff.

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.

Sport and Dental Traumatology: Surgical Solutions and Prevention

Trauma is a worldwide cause of millions of deaths and severe injuries every year, all over the world. Despite the limited extension of the oral region compared to the whole body, dental and oral injuries account for a fairly high percentage of all body traumas. Among head and neck traumas, dental and facial injuries are highly correlated to sport activities, and their management can be a real challenge for practitioners of any specialty. In case of trauma directed to periodontal structures, restorative and endodontic solutions may not be sufficient to achieve a definitive and long-lasting treatment. This article aims to illustrate surgical options and appliances to prevent dental injuries that may be available to the clinicians treating dental trauma involving oral soft and hard tissues.

[Modern approach to the treatment of children with constant teeth avulsion]

THE AIM OF THE STUDY

Was to analyze treatment outcomes in children with constant teeth avulsion treated in Central Research Institute of Dentistry and Maxillofacial Surgery (CRIDMS).

MATERIALS AND METHODS

The study comprised 39 children aged 7-16 years treated in CRIDMS in 2015-2020. In 38 cases from 39 replantation was performed more than 24 hours after trauma. Because of delayed replantation endodontic treatment was needed in 35 cases from 38 (in one case the avulsed tooth was missing). In all 38 cases replantation was followed by splinting with either resin splint made according to original technique proposed by the authors or semi-flexible splints from orthodontic wire fixed with resin composite.

RESULTS

In one case from 39 the avulsed tooth was missing because a dentist the child first consulted was unaware of the possibility of replantation. In 38 children followed-up for 6-57 months the replanted teeth survived and were clinically asymptomatic. There were, however, obvious radiological signs of replacement resorption in 27 (71.1%) cases. Inflammatory resorption was detected in two cases (5.2%) with immature teeth undergoing apexification with calcium hydroxide.

CONCLUSION

Replacement root resorption after tooth avulsion may be seen as relatively favorable outcome preserving more bone tissue than early tooth removal. The rate of replacement resorption, however, would be less in less delayed replantation. The study results proved the necessity for additional education of parents and pediatric dentists on the first aid and treatment tactics for teeth avulsion.

Knowledge on Pre-Hospital Emergency Management of Tooth Avulsion among Croatian Students of the Faculty of Education

The purpose of this study was to evaluate the knowledge regarding tooth avulsion and dental first aid response among Croatian students of the Faculty of Education. A cross-sectional study was conducted among students. Participants (N = 235) were female with an average age of 21.9 ± 2.7 years. The questionnaire contained 10 close-ended questions with two to eleven possible answers. Every participant chose one correct answer. Statistical significance was determined using a Chi-square test. Majority of participants had never received any kind of information on management of a knocked-out tooth. Questions in the nature of tooth injuries, a knocked-out tooth, tooth replantation and whether the knocked-out tooth should be placed back were answered confirmatively by 40.43%, 83.40%, 57.02% and 62.55% of participants, respectively. The questionnaire showed that 18.78% of participants were aware that replantation should be performed within 30 min. The appropriate cleaning and transport medium was chosen by 40.85% and 35.31% of participants, respectively. A nearby dentist would be visited by 66.38% of students. Only 8.08% of participants provided a correct answer to all of the knowledge-based questions. The “I do not know” answer was chosen by 18.30% of participants whenever it was offered. This indicates that the majority (89.78%) were not aware of the fact that the procedure they chose would be inappropriate. The current study confirmed that future primary school teachers have a lack of knowledge for immediate response to tooth avulsion, leaving small chances for a successful prognosis of tooth replantation.

Evaluation of conditioned medium from placenta-derived mesenchymal stem cells as a storage medium for avulsed teeth: An in vitro study

BACKGROUND/AIM

The viability of periodontal ligament cells on the root surface is a major factor that influences the healing of replanted teeth. A suitable storage medium is necessary to preserve avulsed teeth before replantation. Conditioned medium from placenta-derived mesenchymal stem cells (PMSC-CM) contains a variety of growth factors. The aim of this study was to evaluate the effectiveness of PMSC-CM as a storage medium to maintain the cell viability of avulsed teeth.

MATERIAL AND METHODS

Extracted premolars from healthy humans were randomly stored in Hank's balanced salt solution (HBSS) and PMSC-CM for 6, 12 and 24 hours, respectively, at room temperature, and then the ratio of apoptosis of the periodontal ligament (PDL) cells was identified by flow cytometry. Human periodontal ligament stem cells (PDLSCs) were incubated with HBSS and PMSC-CM, respectively, for 6, 12, 24 and 48 hours in 5% CO₂ at 37°C. Then, the cell viability of PDLSCs was determined using the cell counting kit-8 (CCK-8) and a cell cycle assay was performed.

RESULTS

The apoptosis rate of PDL cells in PMSC-CM was significantly lower than that in HBSS at 24 hours (P < .001), while the two groups showed similar cell apoptosis rates at 6 and 12 hours (P > .05). The cell proliferation of PDLSCs treated with PMSC-CM significantly increased compared with the HBSS group (P < .05). The cell cycle assay revealed that the PDLSCs treated with HBSS were arrested at the G1 phase, while there was no difference between the PMSC-CM group and the control group (P > .05).

CONCLUSIONS

Compared with HBSS, PMSC-CM showed better inhibition of apoptosis of PDL cells and promoted the proliferation of PDLSCs. Thus, PMSC-CM could be a promising storage medium for avulsed teeth.

Spectrophotometric insights: calcium hydroxide influences tooth discolorations induced by short-term application of antibiotic/corticosteroid pastes

OBJECTIVES

This in vitro study aimed to assess the influence of a calcium hydroxide dressing regarding the relative color change (ΔE) of enamel-dentin specimens previously exposed to antibiotic/corticosteroid pastes.

MATERIALS AND METHODS

Eighty bovine enamel-dentin specimens with a cylindrical central cavity were randomly allocated to four groups: NEG (empty), POS (blood), LED (Ledermix), and ODO (Odontopaste) (n = 20 each). The materials were applied and sealed with self-adhesive resin luting material. After 3 weeks, the materials were removed and a calcium hydroxide (Ca(OH)₂) dressing was placed in all cavities. After a further 3-week storage period, the cavities were restored with resin-based composite. Spectrophotometric color measurements were taken over 6 months, and ΔE values were calculated. A Tukey's multiple comparison test was performed to assess significant differences within the treatment groups (p < 0.05).

RESULTS

Tooth discolorations were present after 3 weeks in LED (ΔE 29.14 ± 6.55) and POS (ΔE 18.05 ± 7.03); NEG and ODO remained color stable (ΔE 3.2 ± 1.36 and ΔE 2.3 ± 1.16). The 3-week Ca(OH)₂ dressing decreased discolorations of POS (ΔE 15.93 ± 6.63; p = 0.37), whereas LED showed a further significant increase (ΔE 39.55; p < 0.0001). Between the end of the Ca(OH)₂ dressing and the final restoration no significant color changes were observed in any group (p > 0.9).

CONCLUSIONS

Discolorations induced by LED progressed during the Ca(OH)₂ dressing despite careful removal of all residues.

CLINICAL RELEVANCE

Calcium hydroxide might negatively affect the discoloring potential of Ledermix. This highlights the need for direct intracanal application methods of Ledermix ensuring a material-free access cavity or alternative antibiotic/corticosteroid pastes such as Odontopaste should be used.

Effect of laser treatment on outcomes of tooth replantation - A systematic review

Objectives

Over the last few years, several studies have investigated the effect of laser treatment on the replantation of avulsed teeth. We conducted this study to systematically analyse and assess the outcomes and quality of these studies.

Methods

Using the keywords ‘laser’, ‘tooth’, and ‘replantation’, two investigators conducted an electronic search of the PubMed, MEDLINE, Embase, ISI Web of Knowledge and Google Scholar databases. Any studies not meeting the inclusion criteria were excluded. The focused question was ‘Does laser treatment influence the outcomes of tooth replantation?’

Results

Nine studies were included and assessed in this review. In the majority of the selected studies, laser treatment had a positive outcome on preventing root resorption and in promoting periodontal regeneration. However, only three studies were given a quality score of ‘medium’, while six were marked as ‘low’.

Conclusion

Laser irradiation may reduce root resorption and favour periodontal regeneration following replantation of the avulsed tooth. However, more well-designed long-term animal and human studies are needed before lasers can be used clinically to improve the outcomes for replanted teeth.

A Retrospective Case Report on the Longevity of a Reimplanted Closed-Apex Avulsed Canine

For an avulsed tooth with closed apices, it is recommended that the tooth undergoes elective root canal treatment. We however present in this case report a 73-year-old Afro-Caribbean lady, with an asymptomatic, untreated, self-replanted lower left canine which suffered an avulsion 45 years ago. The patient reported no loss of function. This case illustrates the potentially positive outcome of a replanted, non-root-treated, avulsed closed-apex tooth while highlighting the significance of patient-related factors.

Knowledge of General Dental Practitioners and Specialists about Emergency Management of Traumatic Dental Injuries in Qassim, Saudi Arabia

Context. Studies about knowledge of emergency management of traumatic dental injuries (TDIs) which affect children by general dental practitioners (GDPs) and specialists in Saudi Arabia are lacking.

Effects of Er:YAG Laser on the Attachment of Human Periodontal Ligament Fibroblasts to Denuded Root Surfaces Simulating Delayed Replantation Cases: An In Vitro Study

Objective: To investigate the effects of Er:YAG laser on the attachment of human periodontal ligament fibroblasts (hPDLFs) to denuded root surfaces simulating delayed replantation cases. Background data: Dental avulsion is one of the most severe dental traumas, which is often treated with replantation. In delayed replantation scenarios, poor prognosis, including root resorption, usually occurs due to poor root surface conditioning and nonviable hPDLF attachment. Methods: Thirty-six root fragments (5 × 5 × 2 mm) were obtained from periodontium tissue-free premolar root surfaces. Specimens were randomly and equally assigned to the following: Group A, untreated control; Group B, 25 J/cm² and 10 Hz of Er:YAG laser irradiation; and Group C, 50 J/cm² and 10 Hz of Er:YAG laser irradiation. Some specimens in each group were then prepared for surface topography visualization under SEM, others were subjected to coculture with hPDLF suspension, and cell adhesion was further evaluated by SEM. Results: Group A presented homogenous smooth root surface, with fewer and round-shaped cells attached; Group B and C exhibited rather rough and irregular morphologies, and spindle-shaped fibroblasts were firmly attached by numerous lamellipodia and extensions. After a 3-day coculture, the number of fibroblasts attached in Group A was significantly lower compared with the other two laser-treated groups (p = 0.008 < 0.05). No significant alterations were observed between the two laser groups (p = 0.135 > 0.05). Conclusions: Er:YAG laser-treated root surfaces are compatible for the attachment of PDLFs, which suggests that Er:YAG laser irradiation may be used as a promising strategy for root surface conditioning in delayed replantation cases.

Survival of a Maxillary Incisor in an Adolescent Male 16 Years after Its Delayed Replantation

Introduction: Recreational and sport activities, traffic accidents and human behaviour represent the main causes of trauma in young people. Case presentation: This report describes a case of a 15.2-year-old male who suffered uncomplicated crown fracture and avulsion of tooth 11 and uncomplicated crown fracture of tooth 21 due to a bicycle accident. Tooth 11 was dry stored and it was replanted 18 h after the trauma. The root was planed to remove the necrotic periodontal tissue, the pulp was extirpated before replantation and a flexible splint was applied to tooth 13 to tooth 23 for 3 weeks. A replacement root resorption of replanted tooth was suspected at the 3-month radiographic control and suffered a dramatic increase later; minimal infraocclusion, about 1 mm, was observed due to its ankylosis. Sixteen years after the trauma the patient was scheduled for an orthodontic and implanto-prosthetic rehabilitation. Conclusion: Delayed replantation usually has a long-term poor prognosis, so it is very important to promote awareness regarding emergency management modalities in dental traumatology especially among parents, school teachers, and coaches that are usually present at the site of the accident.

Dental Trauma First-Aid Knowledge and Attitudes of Physical Education Teachers: A Systematic Review and Meta-Analysis of the Literature with Meta-Regressions

The main objective of the present review is to evaluate the knowledge and attitudes of physical education (PE) teachers concerning dental trauma first-aid through a systematic appraisal of the literature, meta-analysis and meta-regressions. The entire content of PubMed and ISI/Web of Science was mined. Eligibility criteria for selecting studies were studies evaluating dental trauma first-aid knowledge and/or attitudes and/or the effectiveness of mouthguards use by PE teachers. Articles written in any language and published or accepted by peer-reviewed journals were considered. Methodological quality was assessed using an adapted version of the Downs and Black instrument. Of 15 selected articles, three were of strong quality, three were moderate, and the remaining nine were rated as weak. The majority of studies showed that PE teachers had an inadequate knowledge of the initial management of dental trauma. Specifically, there was a lack of knowledge concerning an appropriate washing and transporting medium and the extra-alveolar period of an avulsed tooth. Due to the inadequate knowledge of PE teachers regarding dental trauma management, specific education should be added to PE classes to improve the emergency treatment of dental injuries.

Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted

BACKGROUND

Traumatic dental injuries are common. One of the most severe injuries is when a permanent tooth is knocked completely out of the mouth (avulsed). In most circumstances the tooth should be replanted as quickly as possible. There is uncertainty on which interventions will maximise the survival and repair of the replanted tooth. This is an update of a Cochrane Review first published in 2010.

OBJECTIVES

To compare the effects of a range of interventions for managing traumatised permanent front teeth with avulsion injuries.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 8 March 2018), Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 2) in the Cochrane Library (searched 8 March 2018), MEDLINE Ovid (1946 to 8 March 2018), and Embase Ovid (1980 to 8 March 2018). The US National Institutes of Health Ongoing Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We considered randomised and quasi-randomised controlled trials that included a minimum follow-up period of 12 months, for interventions for avulsed and replanted permanent front teeth.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, extracted data and assessed the risk of bias. Authors were contacted where further information about their study was required.

MAIN RESULTS

Four studies, involving a total of 183 participants and 257 teeth were identified. Each of the interventions aimed to reduce infection or alter the inflammatory response or both at the time of or shortly after the tooth or teeth were replanted. Each study assessed a different intervention and therefore it was not appropriate or possible to numerically synthesise the data. All evidence was rated as being of very low quality due to problems with risk of bias and imprecision of results. This means that we are very uncertain about all of the results presented in this review.One study at high risk of bias with 69 participants (138 teeth) compared a 20-minute soak with gentamycin sulphate for both groups prior to replantation with the experimental group receiving daily hyperbaric oxygen for 80 minutes for the first 10 days. There was some evidence of a benefit for the hyperbaric oxygen group in respect of periodontal healing, tooth survival, and pulpal healing.One study at unclear risk of bias with 22 participants (27 teeth) compared the use of two root canal medicaments, Ledermix and Ultracal. There was insufficient evidence of a difference for periodontal healing or tooth survival. This was the only study to formally report adverse events with none identified. Study authors reported that Ledermix caused a greater level of patient dissatisfaction with the colour of avulsed and replanted teeth.A third study at high risk of bias with 19 participants compared extra- or intra-oral endodontics for avulsed teeth which were stored dry for longer than 60 minutes before replantation. There was insufficient evidence of a difference in periodontal healing.The fourth study at high risk of bias with 73 participants compared a 10-minute soak in either thymosin alpha 1 or saline before replantation followed by daily gingival injections with these same medicaments for the first 7 days. There was some evidence of a benefit for thymosin alpha 1 with respect to periodontal healing and tooth survival.

AUTHORS' CONCLUSIONS

Based on the results of the included studies, there is insufficient evidence to support or refute the effectiveness of different interventions for avulsed and replanted permanent front teeth. The overall quality of existing evidence was very low, and therefore great caution should be exercised when generalising the results of the included trials. There is urgent need for further well-designed randomised controlled trials.

Knowledge of emergency management of avulsed tooth among intern dental students: a questionnaire based study

Background Traumatic dental injuries (TDIs) represent a major public health problem because of their increasing prevalence and psychosocial impact. Avulsion, one of the most complicated TDIs comprising of 1-16% of all injuries. The present study aimed to assess the current knowledge regarding management of avulsed teeth among dental interns in the city of Hyderabad. Subjects Dental interns of the Panineeya Institute of Dental Sciences and Research Centre, Hyderabad. Method A validated, self-administered 23-item questionnaire was used to obtain demographic details and data on dental avulsion management. Descriptive analyses were carried out on frequency, and a comparison of knowledge score was carried out using a chi-squared test and an independent t-test. Results More than half of the study subjects gave correct responses for most of the items on knowledge regarding avulsion. Around 45.4% of the study populations were categorized with low levels of correct knowledge, with more females (46.6%) having significantly lower levels compared to males (p = 0.03). However, the mean knowledge scores between males (15.5 ± 4.74) and females (16.5 ± 1.68) were comparable (p = 0.15). Conclusion Based on the findings of the study, a majority of dental student interns were aware of the basic procedures to be followed in cases of avulsion.

Effects of Lectin (ScLL) on osteoclast-like multinucleated giant cells' maturation-A preliminary in vitro study

BACKGROUND/AIM

Lectin (ScLL) has been recently evaluated in the oral cavity due to its anti-inflammatory activities. ScLL could be a promising agent for blocking osteoclast activity and preventing root resorption. The aim of this study was to evaluate the effect of ScLL on the viability of the RAW 264.7 macrophage lineage, osteoclast-like maturation and the release of TNF-α and nitric oxide (NO).

MATERIALS AND METHODS

The viability of RAW 264.7 cells was determined by MTT and Alamar Blue assays after ScLL treatment for 24 hours. ScLL effects on RANKL-induced osteoclast-like maturation were assessed by tartrate-resistant acid phosphatase (TRAP) staining and F-actin ring formation. The supernatant was collected to detect the release of TNF-α using ELISA and NO using a nitrite assay.

RESULTS

ScLL suppressed osteoclast-like maturation by decreasing TRAP activity as well as F-actin ring formation. ScLL at 10 μg/mL showed the highest values of NO release compared with all other groups (P < .05). Lower levels of TNF-α were found for the negative control.

CONCLUSIONS

ScLL at 5 μg/mL suppressed osteoclast-like maturation in vitro and had no cytotoxic effect on RAW cell cultures.

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.

Dental Pulp Revascularization in a Replanted Avulsed Immature Maxillary Permanent Central Incisor

An 8-year-old girl sustained an accidental traumatic avulsion of her right maxillary permanent central incisor. She arrived with her mother at a hospital dental clinic with the right maxillary central incisor tooth wrappe in a wet paper towel over 1 hour after the injury. Replantation was accomplished without root surface alteration or root canal intervention. Clinical and radiographic follow-up examinations for over 1 year revealed continued root growth and apical development of the replanted avulsed immature maxillary central incisor with no signs or symptoms of pulpal or periapical pathosis. Excellent outcomes were achieved for periodontal ligament reattachment without removal of the periodontal membrane and pulp revascularization without endodontic intervention.

16-Year follow-up of an avulsed maxillary central incisor after replantation following 10-h storage: An unusual case

Tooth avulsion is a type of dental injury defined as the complete displacement of a tooth out of the alveolar socket, and the lack of prompt treatment measures can result in the loss of function, poor quality of life, and psychological and social problems. However, several factors may not permit the immediate replantation of an avulsed tooth; therefore, delayed replantation has emerged as an alternative to meet the esthetic, functional, and psychological demands of patients. Here it was described that the successful replantation of an avulsed maxillary central incisor in a 9-year-old boy who presented at the clinic with the tooth stored in unfavorable conditions as dry and then in olive oil-milk mixture almost 10 h after the event. The tooth has remained in its socket healthy for 16 years after treatment. The patient was satisfied with both esthetics and function.

Lip and tooth injuries at public swimming pools in Austria

BACKGROUND/AIMS

There is an increased risk of orofacial injuries in swimming pool facilities. Nevertheless, only a few studies have addressed this issue. The aim of this study was to identify the frequency of lip and tooth injuries at public swimming pools in Austria. A further aim was to examine which gender and age groups were affected, where and why these injuries occurred, and whether pool attendants had sufficient knowledge of dental first-aid measures.

MATERIAL AND METHODS

A total of 764 pool attendants in Austria were contacted by telephone and 689 participated in the study (90.2%). The attendants were interviewed retrospectively about accident occurrences in 2014 by a standardized questionnaire. Responses to the provision of first aid and choice of storage medium for avulsed teeth were subsequently evaluated.

RESULTS

The frequency of lip injuries was 19.0%, and tooth injuries were 11.3%. Male bathers (P < .05) and children under 12 years (P < .001) most frequently suffered injuries. The waterslide was the most common accident site. The most common cause of lip injuries was slipping on wet surfaces (39.0%), and for tooth injuries it was collisions with other persons or objects (each 28.1%). The pool attendants' responses were predominantly good or sufficient on first aid, with the exception of what storage medium to choose. Tooth rescue boxes were available in only 8.6% of all pool facilities.

CONCLUSION

Orofacial injuries are a frequently occurring problem in swimming pool facilities. The pool attendants' knowledge on first-aid care of tooth injuries could still be improved.

Awareness of Dental Trauma Management among School Teachers of Kannur, Kerala, India

INTRODUCTION

Dental trauma can overtake dental caries and periodontal disease as the most significant threat to dental health among young people. The prognosis of traumatized teeth depends on prompt and appropriate treatment. The role of school teachers in the prevention of traumatic dental injuries is a topic that has received a great deal of attention in recent years. However, studies conducted in different regions of the world have demonstrated that teachers and other lay people's knowledge about traumatic dental injuries is inadequate and their behavior does not contribute to reduce the sequelae.

AIM

The purpose of this study was to evaluate the knowledge of school teachers about dental trauma and its management in Kannur district.

MATERIALS AND METHODS

The survey was conducted under the Department of Paedodontics and Preventive Dentistry; Kannur Dental College among 303 school teachers randomly selected from 16 schools. Four schools were selected from 16 schools using stratified cluster sampling technique. A cross sectional study design was used. A stratified cluster sampling method was done to select the study subjects. The nature and purpose of the study was first explained to the teachers in local language. Following this the printed questionnaire was distributed to school teachers. The questionnaire was prepared based on the needs of the study after referring similar questionnaires used in studies conducted in different parts of the world.

RESULTS

A statistically significant association was found between the teacher's knowledge regarding trauma and their teaching experience. Out of the total school teachers who participated in the study, 90.1% responded correctly that the teeth most frequently affected by traumatic accidents are the upper front teeth. Nearly 23.4% responded correctly regarding management of traumatic tooth fracture. Almost 46.5% had correct knowledge regarding the reimplantation of avulsed permanent teeth. Only 14.2% responded correctly to the proper storage medium for avulsed teeth.

CONCLUSION

It was concluded from the study that among the school teachers surveyed there was significantly very low knowledge of emergency management of dental trauma.

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.

National Athletic Trainers' Association Position Statement: Preventing and Managing Sport-Related Dental and Oral Injuries

OBJECTIVE

To provide athletic trainers, health care professionals, and all those responsible for the care of athletes with clinical recommendations for preventing and managing sport-related dental and oral injuries.

BACKGROUND

Participation in competitive sports continues to grow at both the interscholastic and intercollegiate levels. Therefore, exposure to, and the incidence of athletic-related injury, including orofacial injury, will also likely increase. At the time of this writing, the leading governing agencies for interscholastic (National Federation of State High School Associations) and intercollegiate (National Collegiate Athletic Association) sports require only protective orofacial equipment (eg, mouthguards) for 5 and 4, respectively, of their sanctioned sports. Although orofacial injuries represent a small percentage of all sport-related injuries, the financial burden associated with these injuries (eg, tooth avulsion) can exceed $15 000 over an adult life. Therefore, effective management of sport-related dental injuries is critical to the long-term financial, physical, and emotional health of people who have experienced dental trauma.

RECOMMENDATIONS

Based upon the current evidence regarding sport-related orofacial injury, we provide recommendations related to planning considerations, education, and mouthguard efficacy, material, fabrication, and care considerations. Additionally, suggested best practices for managing sport-related dental injury are also given for athletic trainers and other health care professionals.

The Effect of Root Coating with Titanium on Prevention of Root Resorption in Avulsed Teeth: An Animal Study

Introduction:

Tooth avulsion is a real dental emergency. If immediate replantation is not performed, the avulsed tooth may be lost due to inflammatory or replacement resorption. This animal study aimed to evaluate the bone response to the titanium coating of the root surface as an artificial barrier, and prevention of resorption of avulsed teeth.

Methods and Materials:

This experimental study was conducted on four male dogs. The dogs were randomly divided into two groups for assessment at two and eight weeks. Four teeth were extracted in each animal. The root surfaces of the test group were coated with a titanium layer using the Electron Beam Deposition system. After 24 h, replantation of the teeth was performed. Two animals were sacrificed after two weeks and the remaining dogs were killed after eight weeks. The presence of inflammation, inflammatory resorption, replacement resorption, periodontal regeneration, periapical granuloma and ankylosis were evaluated through histological analyses.

Results:

Inflammatory root resorption was not present in any tooth except one tooth in the coated group after eight weeks. Replacement resorption was noted just in three of the non-coated teeth after two weeks and two teeth after eight weeks. The McNemar's test revealed that the frequency of replacement resorption in the non-coated group was significantly higher than the coated group (P=0.031).

Conclusion:

Based on the results of this study, it seems that coating the root surfaces of avulsed teeth with titanium may control the replacement root resorption.

Tissue characterization following revascularization of immature dog teeth using different disinfection pastes

Revascularization of immature teeth with necrotic pulps traditionally involves the use of triple antibiotic paste, which may sometimes lead to undesirable complications. The objective of this study was to assess tissue repair in immature dog teeth with apical periodontitis subjected to revascularization, comparing two different pastes used for root canal disinfection. Apical periodontitis was induced in 30 dog premolars. Teeth were randomly divided into three experimental groups: root canals filled with triple antibiotic paste (n = 10); root canals filled with 1% propolis paste (n = 10); and no medication (n = 10). An additional group (n = 10, no intervention) was used as control. After 7 months, the jaws were histologically evaluated for the following variables: newly formed mineralized tissue (present/absent); vital tissue in the canal space (absent/periodontal ligament-like/pulp-like); apical extension of root (present/absent); and severity of inflammatory process (absent/mild/moderate/severe). There were no statistically significant differences among the experimental groups in new mineralized tissue formation and apical root development. The formation of vital tissue in the canal space, in turn, was statistically different between the triple paste and propolis groups: vital tissues were present in all revascularized teeth disinfected with propolis paste (100%), compared to 71% of those disinfected with the triple paste. Severity of inflammatory process was different between the triple paste and no medication groups. The new tissues formed onto canal walls and in the root canal space showed characteristics of cementum and periodontal ligament, respectively. Propolis may have some advantages over the triple paste for the revascularization of immature teeth.

Management of incompletely developed teeth requiring root canal treatment

Endodontic management of the permanent immature tooth continues to be a challenge for both clinicians and researchers. Clinical concerns are primarily related to achieving adequate levels of disinfection as 'aggressive' instrumentation is contraindicated and hence there exists a much greater reliance on endodontic irrigants and medicaments. The open apex has also presented obturation difficulties, notably in controlling length. Long-term apexification procedures with calcium hydroxide have proven to be successful in retaining many of these immature infected teeth but due to their thin dentinal walls and perceived problems associated with long-term placement of calcium hydroxide, they have been found to be prone to cervical fracture and subsequent tooth loss. In recent years there has developed an increasing interest in the possibility of 'regenerating' pulp tissue in an infected immature tooth. It is apparent that although the philosophy and hope of 'regeneration' is commendable, recent histologic studies appear to suggest that the calcified material deposited on the canal wall is bone/cementum rather than dentine, hence the absence of pulp tissue with or without an odontoblast layer.

An experimental model for studies on delayed tooth replantation and ankylosis in rabbits

AIM

To develop an experimental in vivo model to study dentoalveolar ankylosis and osseous replacement resorption after delayed replantation.

MATERIALS AND METHODS

The maxillary right incisors of eight rabbits were extracted and replanted, while the maxillary left incisors served as controls. A special technique for extraction was used, luxating the incisor laterally prior to extraction. Extra-oral root canal treatment was performed. In four of the eight replanted teeth, periodontal ligament was removed using gauze. All teeth were replanted after one-hour dry storage. A horizontal line was drilled on the labial enamel surface of the incisors to enable registration of possible subsequent infraposition. The rabbits were sacrificed after 1 week or 4 weeks, respectively. Percussion test of the teeth was carried out and infraposition was registered. Histological processing and evaluation were performed.

RESULTS

Percussion sound was normal after 1 week and high in the 4 week group; infraposition was noted in all replanted teeth in the 4-week group. Fusion between the bone and dentin was seen in some areas on the root already after 1 week, but there was little or no osseous replacement. Larger areas of ankylosis were seen in the 4-week group although not significant, but deeper progressive osseous replacement was noted in this group. There was no significant difference in ankylosis with regard to periodontal ligament removal or not. Pulp and periodontal tissues were normal in all control teeth.

CONCLUSION

The rabbit tooth model may be useful for experimental in-vivo studies on delayed replantation, subsequent ankylosis, osseous replacement and infraposition.