New philosophy for the treatment of avulsed teeth

Time-course study of genetic changes in periodontal ligament regeneration after tooth replantation in a mouse model

This research focused on analyzing gene expression changes in the periodontal ligament (PDL) after tooth re-plantation to identify key genes and pathways involved in healing and regeneration. Utilizing a mouse model, mRNA was extracted from the PDL at various intervals post-replantation for RNA sequencing analysis, spanning from 3 to 56 days. The results revealed significant shifts in gene expression, particularly notable on day 28, supported by hierarchical clustering and principal component analysis. Gene ontology (GO) enrichment analysis highlighted an upregulation in olfactory receptor and G protein-coupled receptor signaling pathways at this time point. These findings were validated through reverse transcription-quantitative PCR (RT-qPCR), with immunochemical staining localizing olfactory receptor gene expression to the PDL and surrounding tissues. Moreover, a scratch assay indicated that olfactory receptor genes might facilitate wound healing in human PDL fibroblasts. These results underscore the importance of the 28-day post-transplant phase as a potential "tipping point" in PDL healing and regeneration. In conclusion, this research sheds light on the potential role of olfactory receptor genes in PDL regeneration, providing a foundation for developing new therapeutic approaches in tooth replantation and transplantation, with broader implications for regenerative medicine in oral health.

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.

Successful outcome of permanent maxillary incisor reimplanted after 30 hours of extra-oral time-a case report with 5-year follow-up

Key Clinical Message

Tooth reimplantation should be attempted in every possible case with thorough disinfection and impervious obturation. Integration of progressive innovations with recommended protocols can enhance complication free survival in intense situations.

Abstract

The present case describes the unique successful outcome of a tooth reimplanted after the delay of 30 hours. A 21-year old male patient presented with an avulsed #21 after a fall due to electric shock. It was reimplanted according IADT guidelines with the addition of specific irrigation sequence proposed for regenerative endodontic procedures during the endodontic treatment. The final obturation was accomplished by combination of Biodentine and BioRCS root-canal sealer. Subluxated #11 developed symptoms at 6 months and was further managed using recommended endodontic procedure. Both teeth had complication free survival during 5 year follow-up.

Comparative evaluation of the clonogenic capacity of periodontal ligament fibroblasts in Hank's balanced salt solution and egg albumen: An in vitro study

BACKGROUND/AIM

The type of storage media for short-term storage of an avulsed tooth is a critical determinant for the success of tooth replantation. If immediate replantation of an avulsed tooth is not possible, it is advised to store the tooth in a suitable storage medium. The viability and clonogenicity of periodontal ligament fibroblasts (PDLF) determines the success of replantation of an avulsed tooth. The aim of this study was to evaluate the effect on the clonogenic capacity of PDLF's upon storage in Hank's balanced salt solution (HBSS) and egg albumen.

METHODS

Fibroblast cell culture was established from a human premolar tooth extracted for orthodontic purposes. The PDLF cells thus obtained were treated with either Dulbecco's modified Eagle's medium (DMEM; as a positive control), HBSS, or egg albumen for different durations at room temperature and then allowed to grow in DMEM medium until visible colonies appeared which were then fixed, stained, and scored manually.

RESULTS

With increase in the duration of storage in both egg albumen as well as HBSS, there was a reduction in the clonogenic capacity of the PDLF's as compared to DMEM. However, storage in egg albumen led to a significant reduction in the clonogenic capacity of PDLF's (8%-16% for egg albumen) compared to HBSS (80%-90%).

CONCLUSION

Due to its limited ability to support the clonogenicity of PDLF's, egg albumen is a poor storage medium for an avulsed tooth compared to either DMEM or HBSS.

Which is the most recommended medium for the storage and transport of avulsed teeth? A systematic review

BACKGROUND/AIMS

A wide variety of materials has been researched for their use as potential storage media for avulsed teeth, but it is essential to recognize the medium most recommended for improvement of the prognosis of avulsed teeth. The aim of this systematic review was to identify the most recommended medium to store and transport avulsed teeth based on the survival of periodontal ligament (PDL) cells as determined by in vitro studies.

METHODS

Only laboratory-based experimental studies on PDL cells found on adult permanent teeth were included. Data were collected using PubMed, CINAHL plus (EBSCO host), and the Cochrane Library, along with Google Scholar and a hand search. The key terms employed were permutations of [avulsed permanent teeth* OR dental avulsion* OR knocked out teeth*] AND [storage media* OR transport media* OR biological transport* OR PDL cell viability* OR PDL cell survival*]. A customized data extraction pro forma was used to extract the data and to evaluate the quality and risk of bias.

RESULTS

The initial search yielded 978 articles, but only 67 were selected. Milk was the most recommended individual medium followed by Hank's balanced salt solution. Among natural products other than milk, propolis and coconut water were most frequently recommended. Recommendations were based on maintenance of PDL cell viability followed by ease of availability, low cost, and long shelf life.

CONCLUSIONS

Natural products are more effective in maintaining the PDL cell viability compared to synthetic products. Some storage media recommendations were also based upon practical aspects. Although natural products other than milk have more recommendations as a group, milk is the most recommended storage medium individually, based not only on PDL cell viability, but also practical considerations.

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.

Effects of proanthocyanidin, a crosslinking agent, on physical and biological properties of collagen hydrogel scaffold

OBJECTIVES

The purpose of the present study was to evaluate the effects of proanthocyanidin (PAC), a crosslinking agent, on the physical properties of a collagen hydrogel and the behavior of human periodontal ligament cells (hPDLCs) cultured in the scaffold.

MATERIALS AND METHODS

Viability of hPDLCs treated with PAC was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The physical properties of PAC treated collagen hydrogel scaffold were evaluated by the measurement of setting time, surface roughness, and differential scanning calorimetry (DSC). The behavior of the hPDLCs in the collagen scaffold was evaluated by cell morphology observation and cell numbers counting.

RESULTS

The setting time of the collagen scaffold was shortened in the presence of PAC (p < 0.05). The surface roughness of the PAC-treated collagen was higher compared to the untreated control group (p < 0.05). The thermogram of the crosslinked collagen exhibited a higher endothermic peak compared to the uncrosslinked one. Cells in the PAC-treated collagen were observed to attach in closer proximity to one another with more cytoplasmic extensions compared to cells in the untreated control group. The number of cells cultured in the PAC-treated collagen scaffolds was significantly increased compared to the untreated control (p < 0.05).

CONCLUSIONS

Our results showed that PAC enhanced the physical properties of the collagen scaffold. Furthermore, the proliferation of hPDLCs cultured in the collagen scaffold crosslinked with PAC was facilitated. Conclusively, the application of PAC to the collagen scaffold may be beneficial for engineering-based periodontal ligament regeneration in delayed replantation.

PDL regeneration via cell homing in delayed replantation of avulsed teeth

Background

This study was aimed to investigate whether regeneration of periodontal ligament (PDL) like tissue could be promoted by stromal cell-derived factor-1 (SDF1) and bone morphogenetic protein-7 (BMP7) induced cell homing in delayed replantation of avulsed teeth.

Methods

Canine mandibular premolar teeth were first extracted and air-dried for 2 h followed by complete detachment of their PDL tissues. The crown and pulp of the teeth were also removed. Twenty-four roots divided into two groups (n = 12/group) were used for the following in vivo transplantation. The roots of Group A were treated with 17 % EDTA for 24 h to achieve demineralization, and then coated with SDF1 and BMP7 supplemented collagen solution. The roots of Group B were similarly treated except being coated with a pristine collagen solution. The above roots were transplanted in the sockets that formed previously during tooth extraction. At 6 months’ post-operation, PDL-like tissue composed of spindle-shaped cells, capillaries and highly organized collagen fibers was observed in the interstitial space between the avulsed root surface and surrounding alveolar bone in Group A. The neo-fibers inserted deeply and perpendicularly into the cementum and adjacent bone. The periodontium-like characteristics of the neo-tissue was confirmed by immunohistochemical staining for collagen I, fibronectin and osteocalcin.

Results

A high incidence of PDL re-establishment as 42 % was achieved for samples of Group A. However, no PDL-like tissue was found but root ankylosis and replacement resorption as well as inflammatory resorption was observed in the replanted roots of Group B.

Conclusions

It can be confirmed that avulsed teeth could be successfully rescued even in delayed transplantation to avoid dentoalveolar ankylosis or replacement resorption via the current developed cell homing method.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0719-2) contains supplementary material, which is available to authorized users.

MTA versus Ca(OH)2 in apexification of non-vital immature permanent teeth: a randomized clinical trial comparison

OBJECTIVES

The aim of this prospective randomized clinical trial was to compare mineral trioxide aggregate (MTA) with calcium hydroxide (CH) as materials for inducing root apex closure in immature necrotic permanent incisors.

METHODS

The design of this study has been extensively described in the authors' previous report. Children (n = 30), aged from 6 to 18 years and presenting a non-vital permanent incisor, were treated. Half of the group received treatment using MTA, the other half with CH. At recall visits after 6 and 12 months, the presence or absence of a calcified apical barrier was assessed using clinical and radiographic examinations. The anonymised radiographs were evaluated by two independent investigators. Statistical analyses were performed using a Fischer's test (p < 0.05 was used as the threshold for statistical significance).

RESULTS

Presence of a mineralized barrier was observed for 43.8% of the CH group and 64.7% of the MTA group at the 6-month examination. After 12 months, these figures were respectively 50 and 82.4% (p < 0.07). For both groups, pain and tenderness to percussion had disappeared at the 3-month examination.

CONCLUSION

Neither material showed a statistically significant difference at the 6-month examination. At the 12-month examination, the MTA group displayed better results in terms of apical closure. In the CH group, four out of 15 teeth exhibited coronal or radicular fractures after 12 months.

CLINICAL RELEVANCE

Apexification using MTA seems preferable to CH in order to early achieve the coronoradicular filling and to limit the risk of root fracture.

Management and followup of complicated crown fractures in young patients treated with partial pulpotomy

Two cases of young patients with traumatized permanent teeth having complicated crown fractures are reported. Endodontic management included partial pulpotomy by the Cvek technique; restorative management included resin restoration and reattachment of the teeth fragments. Treatments were considered successful in all cases according to the following criteria: absence of clinical symptoms, absence of X-ray signs of pathology, and presence of pulpal vitality 6 to 25 months after treatment.

Management of a transmigrated mandibular canine

The purpose of this article is to report the management of a transmigrated mandibular canine with emphasis on saving the tooth as natural part rather than surgical removal of the transmigrated tooth. There are several treatment options proposed for impacted mandibular canines including surgical removal, exposure and orthodontic alignment, intra-alveolar tooth transplantation (surgical repositioning of a tooth in its alveolar socket) and observation. The technique, surgical repositioning of a tooth involves the surgical extraction of impacted tooth and fixation in the correct position in the dental arch after surgical preparation (correction) of the alveolar socket. It is especially valuable in cases of difficult-to-treat impaction. A repositioned tooth is better substitute than fixed or removable prostheses, and the technique is more cost effective than other methods. Patients with excellent oral hygiene should be considered as preferred candidates for surgical repositioning of tooth. Disadvantages include the invasiveness of surgery, the difficulty of projecting long term stability due to chances of root resorption and loss of gingival attachment.

Recommendations for using regenerative endodontic procedures in permanent immature traumatized teeth

The regeneration of immature permanent teeth following trauma could be beneficial to reduce the risk of fracture and loss of millions of teeth each year. Regenerative endodontic procedures include revascularization, partial pulpotomy, and apexogenesis. Several case reports give these procedures a good prognosis as an alternative to apexification. Care is needed to deliver regenerative endodontic procedures that maintain or restore the vitality of teeth, but which also disinfect and remove necrotic tissues. Regeneration can be accomplished through the activity of the cells from the pulp, periodontium, vascular, and immune system. Most therapies use the host's own pulp or vascular cells for regeneration, but other types of dental stem cell therapies are under development. There are no standardized treatment protocols for endodontic regeneration. The purpose of this article is to review the recent literature and suggest guidelines for using regenerative endodontic procedures for the treatment of permanent immature traumatized teeth. Recommendations for the selection of regenerative and conventional procedures based on the type of tooth injury, fracture type, presence of necrosis or infection, periodontal status, presence of periapical lesions, stage of tooth development, vitality status, patient age, and patient health status will be reviewed. Because of the lack of long-term evidence to support the use of regenerative endodontic procedures in traumatized teeth with open apices, revascularization regeneration procedures should only be attempted if the tooth is not suitable for root canal obturation, and after apexogenesis, apexification, or partial pulpotomy treatments have already been attempted and have a poor prognosis.

Avulsion and storage media

Avulsion of a tooth caused by trauma, and its successful treatment is a challenging situation that a dentist encounters in clinical practice. There is a definitive treatment for the avulsed tooth, which depends on many factors. The immediate replacement and replantation of the avulsed tooth is necessary, but it cannot always be accomplished for a number of reasons. Thus, the tooth should be transported in a suitable medium to maintain the cell viability. The storage medium is one of the important factors that will help the dentist in rendering successful treatment for the avulsed tooth. There is a continuing search for an ideal storage medium. This review paper focuses on the various storage media, with special reference to coconut water.

Replantation after extended dry storage of avulsed permanent incisors: report of a case

A 15-year-old boy lost his maxillary right and left central incisor teeth in a bicycle accident. He was referred to our clinic 1 week after the injury. The crown-root integrities of both the teeth were not damaged. Although the teeth were stored under dry conditions for 1 week, reimplantation of the teeth was planned to retain the teeth in the mouth for as long a period as possible because of the patient's age. Following the debridement and sterilization of root surfaces in 2.5% NaOCl, root canals were prepared and filled with calcium hydroxide. Then, about 2 mm of the apexes were resected to ensure that the roots easily seated in the alveolar socket and the prepared cavities in root ends were obturated with the amalgam. The teeth were placed into their respective sockets and splinted temporarily. The root canal therapy was completed 5 weeks later. Ankylosis was observed radiographically after 10 months. The patient is now 23 years old and he is still able to use both the central incisors functionally. However, there is a pink appearance on the cervical buccal surface of left central incisor because of progressive replacement resorption. In this case, the new treatment plan is to perform a permanent restoration with dental implants following the extraction of both teeth. Even though the long-term prognosis is uncertain, this treatment technique has provided an advantage for the patient in his adolescent period by maintaining the height of alveolar bone and making the provision of an aesthetically acceptable permanent restoration at a later age possible.

Implant Restoration of External Resorption Teeth in the Esthetic Zone

PURPOSE

The purposes of this article were to review the literature for treatment of teeth with external resorption secondary to avulsive injuries and to illustrate treatment of patients with teeth following different clinical scenarios to develop a predictable course of therapy.

MATERIALS AND METHODS

Cases that demonstrate treatment of teeth with external resorption following injury during the growing period, external resorption treated with a delayed approach after tooth extraction, immediate grafting of the extraction site to repair labial bone loss, and immediate implant placement with provisionalization are shown.

CONCLUSION

Based on a review of the literature, the decision to place dental implants to replace teeth with external resorption can be timed depending on the location and type of the resorption, with excellent esthetic results.

Dental Injuries in Sports

The expanding arena of sports and vigorous recreational activities is associated with an increased risk for sports-related injuries, including trauma to the teeth. Because dental professionals may not be present on site, in the best interest of athletes, it is suggested that sports medicine professionals who are present be provided with current evaluative, emergent, and referral protocols for proper management of sports-related dental injuries to address the immediate needs of the athlete and to enhance the long-term prognosis of the traumatized tooth. This article provides information related to some of the more common dental injuries encountered in sports, including crown fractures, root fractures, and traumatic tooth displacements. Use of properly fitted, custom-fabricated athletic mouth guards for the prevention of dental injuries is recommended strongly, as is the inclusion of a dentist on the sports medicine team roster.

Effect of Chlorophyllin on Normothermic Storage of Human Periodontal Ligament Cells

The purpose of the present study was to evaluate whether chlorophyllin could serve as an effective constituent of a storage medium to enhance the human periodontal ligament (PDL) cell viability. Freshly isolated PDL cells from premolars extracted from healthy people were stored at 37 degrees C for 6 h in various solutions: F-medium and Hank's balanced salt solution (HBSS), supplemented with chlorophyllin. From MTT viability assays, the highest cell viability was found in the PDL cells stored in HBSS supplemented with 500 nM chlorophyllin, and the chlorophyllin-treated cells showed a dose-dependent response to concentration. Additionally, the results from flow cytometry showed that 77 to 80% of the PDL cells were in the G0/G1 phases of the cell cycle, which suggested that most were in a stable stage. These result showed that HBSS, supplemented with chlorophyllin, may be a useful solution for preserving the viability of PDL cells.

Root resorption in dental trauma: 45 cases followed for 5 years

We aimed to: (i) study the prevalence of root resorption after luxation or avulsion injuries on permanent teeth referred to our dental clinic over a 3-year period; (ii) study the relationship between type of injury and resultant type of resorption complication; and (iii) evaluate success of treatment protocols for various resorption complications. We observed 1943 patients with dental trauma, aged between 2 and 26 years, referred to the Accident and Emergency Department of the Dental Clinic, University of Brescia, from 1st September 1997 to 31st December 2001. Of these, 261 permanent teeth had sustained luxation (n = 188) or avulsion (n = 73) injuries. Permanent teeth luxation and avulsion injuries occurred most often in upper incisors (75%) of patients mostly aged 12-21 years, with males more commonly affected than females (68.3% vs. 31.7%). These cases were followed for 5 years, and complications and response to treatment were recorded. Root resorption was observed in 45 (17.24%) of these cases. Of the 45 cases with resorption, 9 were associated with luxation injury (20%) while 36 (80%) with avulsion. We distinguished 30 cases of inflammatory root resorption (18 transient and 12 progressive) and 15 cases of ankylosis and osseous replacement. When resorption was recognized, quick and effective treatment could still result in an excellent functional and aesthetic outcome for these teeth.

Regulatory mechanisms of periodontal regeneration

The periodontal ligament, located between the cementum and the alveolar bone, has a width ranging from 0.15 to 0.38 mm. Regeneration and homeostasis of the periodontal ligament are highly significant functions in relation to periodontal therapy, tooth transplantation or replantation, and orthodontic tooth movement. The purpose of this review is to discuss the regulatory mechanisms of regenerative and homeostatic functions in the periodontal ligament based on currently published studies and also on our own experimental data. We consider the capability of the ligament tissue to promote or to suppress calcification in connection with bone and cementum formation and the maintenance of the periodontal ligament space. Also discussed are the involvement of the periodontal ligament tissue in the regenerative ability, cell proliferation, growth and differentiation factors, extracellular matrix proteins, homeostatic phenomena, function of Malassez epithelial rests, tooth movement, or occlusal loading. Regulatory mechanisms for regeneration and homeostasis of the periodontal ligament are hypothetically proposed.

Immediate repositioning of an accidentally extruded immature premolar after extracting root remnants of the primary molar

This article describes a case where during an extraction of a primary molar's root remnant, the successor permanent tooth was accidentally extruded. The extruded tooth was immediately repositioned to its right position in the socket and it erupted normally after a short time. After 2 years, a routine clinical examination revealed normal appearance of the premolar in the dental arch. A radiograph demonstrated an obliterated coronal part of the pulp, normal root length, a slightly open apex and no periapical inflammation.

Diagnosis and management of dental injuries in children

Approximately half of children sustain some type of dental injury. Management of injuries to the anterior teeth of preschool children is directed toward minimizing potential damage to the developing permanent teeth; therefore, heroic measures to save primary teeth are not indicated. Crown fractures in the permanent dentition, even those exposing the dental pulp, can be successfully treated hours after an injury. Prompt referral for dental treatment is advisable. Displacement injuries to permanent teeth constitute genuine dental emergencies in which the prognosis is directly related to the timeliness of treatment. Avulsed permanent teeth should be immediately reimplanted by any capable person. If that is impossible, the teeth should be placed in cold milk and the child referred for immediate treatment by a dentist. Mouthguards prevent dental injuries but are not widely used outside of a few organized sports. Efforts should continue to promote mouthguard use in all contact sports.

Variations in the presenting and treatment features in reimplanted permanent incisors in children and their effect on the prevalence of root resorption

OBJECTIVE

To examine variations in the presentation and treatment of reimplanted incisors in children and to determine the effect of these on the prevalence of external root resorption.

SETTING

Departments of Paediatric Dentistry, Belfast and Newcastle upon Tyne.

DESIGN

Recording of the timing of the injury and the storage mediums (including air) and of reimplantation, the stage of root development, the degree of contamination and the time of commencement of root treatment. Cases were reviewed clinically and radiographically at intervals of 3 months. Root resorption was classified as present or absent. Logistic regression and cross-tabulations were produced with the presence of resorption set as the outcome.

RESULTS

128 reimplanted permanent incisor teeth, their median dry time prior to reimplantation being 15 minutes (range 4-52 mins), the median time in a liquid medium being 45 minutes (range 0-650 mins), with a median splinting time of 15 days (range 4-52 days) and a median pulp extirpation time of 15 days (range 0-612 days). There was a lower prevalence of resorption when the period of dryness was less than or equal to 5 minutes (p = 0.025). The prevalence of resorption in teeth with no visible contamination was 57.1%, for those with contamination which were washed clean it was 75%, in those rubbed clean it was 87.5%, and it was 100% for those reimplanted with visible contamination still present (p = 0.014). The corrected odds ratio for contamination was 2.99 and for an extension of 10 minutes of dryness it was 1.29.

CONCLUSION

The degree of contamination and the period of dryness were the major risk factors for resorption in this study of reimplanted teeth in children.

Dentoalveolar trauma

Dentoalveolar injuries represent a serious dental problem for the patient. Time from injury to treatment is a major factor in the outcome of many of these injuries. To decrease dental pain and suffering and enhance the prognosis, medical personnel must recognize the presence of dentoalveolar injuries and consult with, or refer the patient to, a dentist as soon as possible.

Traumatic dental injuries: current treatment concepts

In an overview of traumatic injuries in the permanent dentition, the authors describe the classification of, assessment of and treatment strategies for managing such injuries. They explore pulpal and periodontal considerations, as well as methods of minimizing complications. In addition, they suggest preventive strategies and future directions for trauma management.

Root resorption of replanted teeth: an SEM study

Two replanted and subsequently expelled upper central incisors were observed under a scanning electron microscope to study the changes brought about by root resorption. The severity of resorption and the distribution of the affected areas were different in the two specimens. In the first case, large, deep excavations were found along a continuous bone defect which exposed the opposite root canal wall. Bacteria-like elements were found on the bottom of the eroded areas both on the outer and on the inner root surfaces. In the second case, resorption denuded the apical portion of the metal post. Erosive lacunae were visible in some areas while tubiform excavations were present close to the apical margin exposing the collagen network. The roots in the first case likely underwent inflammatory resorption while replacement resorption was thought to have occurred in the second case.

[Replantation of avulsed immature permanent teeth. Results in 39 cases after an average of 2.5 years]

The aim of this investigation was a critical assessment of the short- and medium-term results of replantation of immature, avulsed permanent teeth. Thirty-nine teeth were investigated after 2.5 years on average. Only 7 teeth (18%) had been replanted within 5 min after avulsion. Sixteen teeth (41%) showed revascularisation or ingrowth of alveolar bone into the pulp. Twenty-two teeth (56%) showed signs of ankylosis, 6 (15%) had been exfoliated or extracted. Seventeen teeth (77% of the ankylotic ones) exhibited an alveolar growth arrest of 1.5 mm per 10 cm body growth. By planimetric assessment, the yearly loss of root dentin by replacement resorption was about 15%. The appearance was compromised in 11 cases (33%) by severe discoloration. In spite of intense therapeutic effort and partial success, the results must be classified as unsatisfactory. In avulsions of immature permanent teeth, replantation therefore has to be considered an intermediate solution. Since the main reason for a failure is extended extra-oral unphysiologic storage, replantation by lay helpers immediately after the accident should be propagated as a first-aid treatment to improve the situation of the replanted tooth. In addition, more attention should be paid to preserving teeth in tissue cultures before replantation.