Prognosis of replanted primary incisors after injuries

Between 1979 and 1997, 58 avulsed primary teeth were treated at the Pedodontic Clinic of Niigata University Dental Hospital. Among these, we replanted six avulsed incisors of four patients and treated two teeth of two patients replanted at other dental clinics. Referring to the clinical records, oral photographs and radiographs, we examined the injury age, cause of injury, condition of tooth storage, length of time until replantation, and also the prognosis after replantation. Three teeth of two cases remained until eruption of their permanent successors, and one tooth of one case remained under observation without extraction. Although the other four teeth of three cases resulted in extraction, no secondary infection was detected due to replantation. The following reasons were suspected for the poor prognosis of the four teeth. One avulsed tooth was not fixed immediately after replantation. One replanted tooth might not have been compatible with the alveolar socket. In the other two teeth, the periodontal vital tissues might have been removed before replantation. It is generally suggested that replantation of primary teeth is not a good option. However, from the present results, it was considered that replantation can be an effectual method when the condition of the avulsed primary tooth is suitable.

Immediate replantation of maxillary incisors in rats: effects of tooth immersion in sodium fluoride and subsequent removal of the periodontal ligament

The advantages and disadvantages of maintaining the periodontal ligament (PDL) in immediate replantation as well as chemical treatment of the root surface have been a matter of discussion because the vitality of such tissue in surgery is always questioned. This study evaluated the effects of conserving the tooth in sodium fluoride and the removal of the PDL before replantation of incisors in rats. There was more cementum-dentin resorption in the group with the PDL. The group without the PDL showed more discreet resorption, repair occurred through the newly formed bone tissue in the PDL space and ankylosis was more extensive than in the group with the PDL.

Reimplantation of an avulsed tooth after prolonged storage

This report demonstrates that if an intact avulsed tooth is retrieved, stored carefully and treated, it can be re-implanted successfully, even after more than 42 hours outside the alveolus. The tooth can regain its position as a stable member of the arch, and its osseous and gingival complex can be restored.

[Application of enamel matrix derivative for tooth transplantation and replantation]

OBJECTIVE

The purpose of this study was to clarify the effects of enamel matrix proteins on the regeneration of periodontal ligament (PDL), during transplantation and replantation therapy.

MATERIALS AND METHODS

[Exp 1] The crown and root apex of extracted dog teeth were removed and the remaining root separated longitudinally. Two-thirds of crown-side PDL and cementum were removed. Prepared teeth were covered with propyleneglycol alginate (PGA) both with and without enamel matrix derivative (EMD) and cultured for 0-14 days. The outgrowth length of the tooth was measured and histological observation done. [Exp 2] The incisal teeth of adult dogs were extracted and 2/3 of crown side PDL and cementum removed. Prepared teeth were treated with PGA containing EMD (EMD group). No tooth treatment was done in the control group. Following PGA treatment, teeth were replanted. The animals were sacrificed at 2 and 4 weeks after replantation and histological observation performed.

RESULTS

[Exp 1] The outgrowth length of the EMD group was longer than that of the other groups. The width of proliferated cell layer on the tooth in the EMD group was thicker. [Exp 2] Ankylosis surface of the EMD group was smaller than that of the control group. In the control group, the region of ankylosis increased longitudinally. In the EMD group, the newly-formed cementum was predominantly cellular cementum.

CONCLUSION

The results suggested that enamel matrix protein enhance the regeneration of PDL and prevent tooth ankylosis in transplantation and replantation therapy.

The radicular groove: its potential clinical significance

This report examines three clinical cases of root-filled teeth with primary endodontic lesions. During endodontic surgery, an area of incomplete root bifurcation beginning in the coronal or middle third of the root surface and terminating at or near the apical foramen were observed. The radicular grooves of two teeth were eliminated using a round bur ("saucerization"), and the resulting defect was filled with a bone substitute or calcium sulfate and covered by an absorbable collagen membrane. The other tooth was extracted, the groove was eliminated with a similar technique, and the tooth was replanted. Bacteria have been reported in chronic apical lesions. Our observations suggest that after conventional endodontic therapy, the etiology of a nonresolving primary endodontic lesion may be bacteria of endodontic origin sequestered within the protective confines of an apical-radicular groove.

Bonded arch bars to manage traumatic injuries to the teeth and alveolar bone

A simple, rapid, painless, and bloodless method of successfully treating avulsed and partially avulsed teeth with or without associated dentoalveolar fractures is presented for management by the general practitioner in the office. It is a bonding technique with the key elements being a prefabricated malleable mesh backed arch bar in combination with any light curing composite procedure that is standard in the individual's office.

Postreplantation management of avulsed teeth: an endodontic literature review

Today's dental treatment goals are directed at reducing the incidence of root resorption resulting from periodontal ligament devitalization or pulp necrosis. Although the American Association of Endodontists recommends the use of long-term therapy, short-term therapy may be utilized with confidence in well-defined clinical applications. Early final obturation with gutta-percha will increase the long-term prognosis in those cases where patient motivation is questionable or long-term follow-up prior to obturation is not possible. However, where inflammatory resorption is already present, long-term calcium hydroxide therapy is indicated. Long-term post treatment follow-up is imperative in both calcium hydroxide therapies.

Clinical management of avulsed permanent incisors using Emdogain: initial report of an investigation

The enamel matrix derivative Emdogain was recently approved for clinical use in a number of countries, including Canada. It has been shown to stimulate regeneration of periodontal ligament following periodontal surgery in adults. This paper reviews pertinent clinical and laboratory studies of Emdogain and describes the protocol and methods used for a longitudinal outcome study of replantation of avulsed permanent incisors in children and adolescents. Application of these methods is described in an illustrative case report of Emdogain use. This paper is meant to inform clinicians and guide those who are instituting similar investigations.

Five-year follow-up of successful intentional replantation

Intentional replantation has been practised for many years as a treatment modality for pulpless teeth. Although the success ratio for intentional replantation is far below that for routine or surgical endodontics, one should consider this procedure as an alternative to tooth extraction. Two cases of mandibular second molars which were treated with intentional replantation and retrograde fillings are reported in this article. At the 5-year recall visit, the radiographs showed no evidence of pathological changes.

Re-innervation in the canine periodontal ligament of replanted teeth using an antibody to protein gene product 9.5: an immunohistochemical study

The re-innervation process in the periodontal ligament of replanted canine teeth was examined by immunohistochemistry for protein gene product 9.5 (PGP 9.5), a general marker for neurons, and by electron microscopy. Within 1 week of replantation, the periodontal fibers had regenerated, filling the narrow spaces between the alveolar bone and the root surface around the cervical and apical regions. Near the root apex, however, no PGP 9.5-immunopositive nerve fibers were found in the regenerated periodontal ligament except for those in the alveolar half of the ligament. At 2 weeks after replantation, many nerve fibers positive for PGP 9.5 had ascended the periodontal ligament from the thick nerve bundles located near the root apex. Fine nerve endings showing complicated ramification were also present in the apical region. By 3 or 4 weeks after replantation, the vascular network was regenerated and principal periodontal fibers were re-established throughout the entire length of the periodontal ligament. The extensively ramified PGP 9.5-immunopositive structures had increased in thickness and density and showed characteristic tree-like profiles by 3 weeks. Electron microscopy confirmed that most of these structures were Ruffini-like endings, and demonstrated that such nerve terminals were almost regenerated by 4 weeks post-replantation. These results indicated that, in the periodontal ligament of replanted canine teeth, the regeneration of the nerve fibers including mechanosensory receptors first showed signs of regeneration by 2 weeks following tooth replantation and proceeded rapidly thereafter. Regeneration of the periodontal ligament including fiber architecture as well as vascular and neural elements was almost complete by 4 weeks after replantation.

Muco-gingival and periodontal health recovery following reimplantation of teeth

Reimplantation of avulsed permanent teeth following traumatic injuries is a widely accepted therapeutic measure; however, though periodontal healing is considered to be the major determinant of long-term survival of reimplanted teeth, the mucogingival reaction to reimplantation has never been assessed. In the present study, hygiene level and gingival inflammation of 13 reimplanted teeth were assessed according to the plaque index (PI) and the gingival index (GI) around both reimplanted and control teeth. The periodontal condition was evaluated by measuring probing depth and probing attachment level at the same location. The clinical parameters of the reimplanted teeth were compared with those of contralateral teeth with the help of the non-parametric Wilcoxon signed ranks test. There were no statistically significant differences in PI and GI scores at any points of measurements around both reimplanted and control teeth; neither did probing depths and probing attachment levels differ between reimplanted and contralateral teeth. The results of the present study indicated that the muco-gingival reaction following traumatic avulsion did not affect the long-term prognosis of the reimplanted teeth.

Effect of endodontic smear layer and various solvents on the calcium ion diffusion through radicular dentin--an in vitro study

External root resorption and ankylosis remains the major cause of failure of replanted teeth. This study was conducted to explore the different ways to increase the pH of periradicular area in order to overcome the problem of root resorption and ankylosis. 60 freshly extracted permanent anteriors were used after removing the crown at CEJ. After biomechanical preparation Ca (OH)2 was injected and assays were done using EDTA, Citric and tannic acid Assays were repeated. Calcium diffusion and pH in the root exterior was measured using spectrophotometer. Results showed that dentin is permeable to calcium & hydroxyl ions and placement of Ca (OH)2 in the canal resulted in its increased recovery and alkaline pH periradicularly. Smear layer removal did not result in significant increase in Ca++ recovery or alkaline pH however combination of EDTA & NaOCl was found best than the other two.

[An experimental study on transplantation of frozen autogenous tooth-mandible compound]

OBJECTIVE

To study the feasibility of reserving the teeth in the transplantation of frozen autogenous mandible.

METHODS

Forty adult Wistar rats were used for these operations of transplantation of frozen autogenous tooth-mandible compound (ATMC) and fresh ATMC. Then the healing process after transplantation of frozen ATMC and fresh ATMC was compared by clinical, radiographical, histological and microangiographical observation.

RESULTS

There were no significant differences between the healing process of frozen ATMC and that of fresh ATMC, and the fibres of regenerated periodontal membrane which maintained the dental root in normal position could be imbedded in the newly formed cementum.

CONCLUSION

It is feasible to transplant the frozen ATMC for reconstructing the mandible and improving its function in clinic.

Inappropriate treatment of traumatic dental injuries

Traumatic dental injuries are emergencies that must be treated expediently and efficiently to reduce pain and to restore function and appearance. With an increase in the incidence of traumatic dental injuries in our community (I) it is essential that the dental practitioner has "up-to-date" knowledge of dental trauma. The peak incidences of injury are 2-4 years and 8-10 years of age, with statistics revealing 30% of children suffer trauma to the primary dentition, and 22% of children suffer trauma to the permanent dentition by the age of 14 (I). The male to female ratio is 2:1. Aside from the emergency treatment and clinical decisions that must be made at the time of injury there is a need for long-term follow-up because of the high incidences of complications (2, 3). The factors that will influence the extent of injury will be energy impact, the direction of the impacting object, its shape and its resilience (4). Recent articles have raised concerns about inappropriate treatment for traumatic dental injuries (5, 6). This report will look at one such case.

Investigations on a cell culture medium for storage and transportation of avulsed teeth

Non-physiologic storage of avulsed teeth leads to a high incidence of root resorption, resulting in poor prognosis. This study investigated the suitability of specially composed cell culture media for storage of extracted teeth for up to 48 hours. Autoradiographic investigations revealed that the proliferative activity of periodontal ligament (PDL) cells of teeth stored in cell culture medium for up to 48 hours increased with storage time. Studies on proliferation of PDL cells after storage of teeth in different media for up to 24 hours demonstrated that the proliferative activity is dependent on the composition of the medium. Immunohistochemical investigations with markers for cell proliferation revealed that pulp cells of extracted immature teeth show numerous proliferations after storage for up to 24 hours in a special cell culture medium but few proliferations after storage in Hanks Balanced Salt Solution (HBSS). The investigations indicate that a special cell culture medium can preserve cell viability of PDL cells adhering to extracted teeth for at least 48 hours. The in vitro results are confirmed by a case presented: After storage of two upper central incisors for 36 hours in the cell culture medium the teeth could be successfully reimplanted after extraoral insertion of titanium posts into the root canal (auto-alloplastic reimplantation). Clinical and radiological follow-up examinations for 12 months revealed normal periodontal healing.

Repair of a root perforation with a resin-ionomer using an intentional replantation technique

The repair of a root perforation can be accomplished using different materials and techniques. When the defect is surgically inaccessible, the tooth can be carefully extracted, repaired extraorally, and placed back into the socket. This procedure, known as intentional replantation, is often a measure of last resort in an heroic effort to save a hopeless tooth. This case report describes the treatment of a tooth with an iatrogenic root perforation and the subsequent healing of the surrounding periodontium using an intentional replantation technique and resin-ionomer to repair the root defect.

Treatment of root perforation by intentional reimplantation: a case report

Intentional reimplantation is defined as a procedure in which an intentional tooth extraction is performed followed by reinsertion of the extracted tooth into its own alveolus. In this paper, intentional reimplantation is described and discussed as a treatment approach to root canal instrument separation in conjunction with root perforation. An 8-year follow-up case report is presented. The reimplanted tooth is now a fixed bridge abutment. Although successful in this case, the intentional reimplantation procedure should be considered a treatment of last resort, that is, when another treatment option is not viable for the treatment of root perforation/instrument retrieval.

Management of an avulsed primary incisor

The case describes the management of an avulsed maxillary central primary incisor of a 3 1/2-year-old girl. The tooth was retained in the oral cavity for 30 min. After replantation it was splinted for 17 days. At day 11 the root canal was completely instrumented and obturated with a calcium hydroxide paste. The 1-year follow-up documented no pathologic clinical or radiographic findings. One and a half years after the trauma the tooth was extracted since a fistula and extensive external inflammatory resorption had developed. The permanent successor erupted along with its neighboring central incisor without any complications 6 months later. Conventional approaches for treating avulsed permanent teeth could also be applied to avulsed primary incisors to preserve them for a certain period without the additional risk of damaging their developing permanent successors.

Optimal esthetics in single-tooth replacement with the Re-Implant system: a case report

PURPOSE

This report demonstrates the use of root-analogue titanium implants for single-tooth replacement.

MATERIALS AND METHODS

A maxillary lateral incisor was removed and a custom-made one-stage, root-analogue titanium implant (Re-Implant) with an apical extension and a healing cap was fabricated and placed immediately after tooth extraction. Six months later the healing cap was removed, an impression was taken, and a porcelain-fused-to-metal crown was fabricated and cemented.

RESULTS

No complications occurred during the healing period. A good esthetic result was achieved with the final ceramometal crown. Bony resorption and buccal soft tissue recession led to a slight discoloration of the marginal periimplant mucosa.

CONCLUSION

Further research into the modalities of the immediate placement of root-analogue implants is needed to obtain predictable esthetic results concerning the soft tissue environment.

Results of intentional replantation of molars

PURPOSE

This study evaluated the treatment outcome of intentional replantation of molars.

PATIENTS AND METHODS

Twenty-nine patients were treated with intentional replantation because conventional apicoectomy was not possible. The success rate was judged by clinical and radiographic parameters.

RESULTS

One molar (3%) had to be removed because of pain and mobility 4 weeks postsurgery, and three molars (11%) had to be removed during the first year because of periodontal problems. Four molars (14%) showed periodontal problems or root resorption, but are still in function and causing no obvious problems to the patients. Twenty-one molars (72%) were successfully treated.

CONCLUSION

Intentional replantation is a reliable and predictable treatment for those cases in which conventional apicoectomy is hampered because of anatomic limitations or patient factors.

Evaluation for tooth stabilization and treatment of traumatized teeth

Thorough evaluation and correct treatment of traumatized teeth improve their chances for survival. This article provides an overview clinical evaluation and how best to treat the tooth that has been traumatized. The rationale and techniques for tooth stabilization of the traumatized tooth will also be presented.

Osteointegration of a replanted tooth followed by RVG densitometry

The frequency of dental traumas in children has been increasing. This work reviews a patient aged 9 who had the 2-day old fracture of the root of first permanent central incisor skewed palatinally 3 mm under the bone. The tooth was extracted, its canal filled with calcium hydroxide, and within less than 10 minutes the tooth was replanted and fixed by a metal splint. Daily follow-up did not show either pathological perioodontal changes or subjective pain symptoms. After 3 months the tissue density of both incisors was the same, i.e. the fractured tooth showed entire osteointegration.

Forced eruption: a multidisciplinary approach for form, function, and biologic predictability

There are several treatment options for patients with coronal fractures, subgingival caries perforations, and root resorption. Frequently, forced eruption is not considered, although in many cases of single-rooted teeth, forced eruption is the "gold standard" for producing an esthetic result without jeopardizing periodontal support for adjacent teeth. Sufficient tooth length, achieved through forced eruption, ensures the periodontal health of the "biologic width" and crown margin and thus a successful restorative outcome.

Responses of macrophage-associated antigen-expressing cells in the dental pulp of rat molars to experimental tooth replantation

Bacterial infection of the dental pulp is a major hindrance to successful pulp regeneration after tooth replantation. This study examined how macrophages and class II molecule-expressing cells of the pulp respond to tooth replantation, on the hypothesis that they contribute to the defence and repair of the traumatized pulp. Upper right first molars of 5-week-old male Wistar rats were replanted immediately after extraction; contralateral untreated teeth served as controls. Pulpal cells expressing macrophage-associated antigens were immunohistochemically demonstrated at 0 h (immediately after the replantation) to 84 days postoperatively using antirat monoclonal antibodies OX6 (anti-class II molecules), ED1 (pan-macrophage antibody, reactive also with dendritic cells) and ED2 (anti-resident macrophages). Between 3 and 7 days postoperatively, ED1+ and OX6+ cells, but not ED2+ cells, were concentrated in areas of degeneration formed in the coronal pulp, and frequently showed a marked accumulation along the pulp-dentine border of the cuspal area. Confocal laser scanning microscopy revealed that some of the OX6+ cells with a dendritic profile extended several cytoplasmic processes into the dentinal tubules communicating with the enamel-free area at the tip of the cusp. From 14-84 days, approx. two-thirds of specimens exhibited pulp-tissue regeneration with increasing formation of reparative dentine. Following the formation of sound reparative dentine, cells positive to each antibody were distributed more centrally in the pulp than in the controls, and thus did not show any accumulation along the pulp-dentine border. However, in the other specimens where a bone-like hard tissue had formed in the pulp chamber, many ED1+ and OX6+ cells were still concentrated in the remaining pulp tissue and showed a marked accumulation along the pulp dentine border. Few ED2+ cells were observed in these specimens. These findings suggest that, following tooth replantation, exudative macrophages are actively engaged in eliminating dentinal tubule-derived infectious stimuli and that class II molecule-expressing cells, most probably containing dendritic cells, are positioned strategically at the outermost portion of the injured pulp to monitor incoming antigens. The intensity of the pulpal defence reaction may be dependent on the status of hard-tissue formation, which influences the amount of incoming antigens.

[Therapeutic management of traumatic avulsion of permanent teeth]

Management of avulsed permanent teeth requires perfect knowledge of the different parameters influencing the short and mid-term and above all long-term prognosis. Based on a review of the literature and the analysis of 50 cases cared for in our unit enables us to propose, in accordance with the extra oral delay and the degree of dental maturation, a protocol for the different emergency situations. This clarification emphasizes the contribution of new preserving solutions which allow reimplantation delays up to 24 hours without effect on prognosis.

Interim storage of avulsed permanent teeth

This literature review examines the effects of extra-alveolar duration and storage conditions on the healing of the periodontal ligament (PL) of avulsed teeth following replantation. A critical assessment of the so-called "reconstitution theory" for PL cells is also presented. The ideal treatment for an avulsed tooth is immediate replantation (i.e. less than five minutes). Unfortunately, immediate replantation is not the norm, and most avulsed teeth experience delayed replantation. The greatest risk to the vitality of the PL cells attached to the root of an avulsed tooth is desiccation. Not surprisingly, storage media affect PL healing. Storing avulsed teeth in an isotonic liquid is superior to dry storage. Numerous studies support the use of Modified Eagle's Medium, Hank's Balanced Salt Solution (HBSS), ViaSpan, saline, milk, and saliva as storage media. A recent study has suggested that chicken egg white may also prove to be a suitable storage medium for avulsed teeth. Of these media, only saliva is always present at the scene of an accident, however. Milk can usually be obtained on short notice, but even 10 minutes of desiccation can affect the outcome of replantation. From a practical standpoint, milk packed in ice seems to be the best alternative for the temporary storage of avulsed teeth, due to its wide availability and the minimal detrimental effects it has on PL cells. There is no evidence to support the suggestion that HBSS or any other media will "reconstitute" the PL cells when the extra-alveolar duration of avulsed teeth is greater than 30 minutes.

Complication from an extraction of a primary tooth

A complication that occurred during the extraction of mandibular right second primary molar is presented. The clinical and radiographic examinations were done; however, the germ of the second premolar came out with the primary tooth. In the same session, replantation was done and monitored very often for two years. The tooth erupted normally into occlusion without any abnormality in dental arch.

The influence of storage conditions on the clonogenic capacity of periodontal ligament cells: implications for tooth replantation

Viable periodontal ligament (PL) cells are required for PL healing of avulsed teeth following replantation. If immediate replantation cannot be accomplished, the ability of PL progenitor cells to reproduce (clonogenic capacity) and recolonize the wound may be extended by prevention of desiccation and storage in physiological media. This investigation examined the effects of storage in saliva, milk, Hank's balanced salt solution (HBSS) and Eagle's medium (alpha MEM) on the clonogenic capacity of human PL progenitor cells at 30 and 60 min extra-alveolar time. Twenty erupted human premolar teeth extracted as atraumatically as possible for orthodontic purposes were used in the present study. Fifteen premolars were placed immediately in freshly collected autologous saliva at room temperature, (+ 23 degrees C) for 15 min. These 15 premolars were next divided into three groups of five and stored in either saliva, milk or HBSS at + 4 degrees C in plastic cups surrounded by ice. The remaining five teeth served as positive controls and were immediately placed in alpha MEM at + 4 degrees C. PL tissue was scraped from one-half of the root surface with a scalpel at 30 and 60 min total extra-alveolar duration. Cells were released from the tissue sample with a 30 min enzymatic digestion procedure and the cells from the tissue samples analyzed for clonogenic capacity. There was a reduction in clonogenic capacity with time for all protocols. Periodontal ligament cells stored in alpha MEM showed the least reduction between 30 and 60 min and the greatest reduction was observed for PL cells stored in saliva. The difference in clonogenic capacity following transfer from saliva to milk or HBSS was not significant at 30 min. At 60 min, cells transferred from saliva to HBSS had a statistically higher percentage of clonogenic cells than those transferred to milk (5.9% vs. 3.5%; P < 0.05). We conclude that immediate storage of avulsed teeth in autologous saliva, followed by transfer to chilled milk, preserves the presence of sufficient progenitor cells in the PL to warrant replantation and the possibility of PL healing at 60 min extra-alveolar duration.

[Relapse after endodontic treatment: endodontic retreatment or apex resection?]

In many cases, unsuccessful endodontic treatment is followed by apicoectomy. Endodontic retreatment, however, could be an appropriate alternative for apicoectomy more frequently. In this paper indications, specific problems and treatment methods are presented for endodontic retreatment, apicoectomy and intentional replantation.

[Injuries to the permanent teeth. Periodontal lesions]

Tooth luxations are relatively common. In case of concussion or subluxation the tooth is not displaced. The treatment will consist of relief of the tooth. Most frequent complications are pulp necrosis and obliteration of pulpal tissues. In case of extrusive luxation pulpal tissues and the periodontal ligament are injured. When tooth mobility is increased flexible splinting should be considered. Endodontic treatment is necessary after extrusive luxation of a tooth with completed root formation. Teeth with open apex often show pulpal obliteration after extensive luxation. Lateral luxation is more complex than extrusive luxation since the alveolar bone is also damaged. Repositioning and splinting of the tooth are necessary. When the apical foramen in closed, endodontic treatment will be necessary. Teeth with incomplete root formation will develop pulp obliteration. Following lateral luxation, external root resorption and loss of marginal bone are not infrequent. Intrusive luxation is the type of trauma with most unfavorable prognosis. All intruded teeth will become necrotic and external root resorption and marginal bone loss are frequent. There is no consensus regarding the therapeutic approach. Orthodontic extrusion or surgical mobilisation are possible options. In case of avulsion, both the pulpal tissues and the periodontal ligament are disrupted. Preservation of the vitality of the periodontal ligament covering the root will determine the prognosis of the reimplanted tooth. Therefore the tooth will be repositioned as soon as possible. When this is not possible, milk or a specific solution are most appropriate for tooth conservation. When the reimplanted tooth has complete root formation, devitalization will be performed one week after after repositioning. In case of a tooth with open apex revascularisation can be awaited. Healing of the periodontal ligament will determine prognosis. When a normal ligament is obtained during healing or when surface resorption is obtained, the tooth can be preserved for a long period. When progressive replacement resorption (ankylosis) develops, most teeth can remain in position for about 10 years. When inflammatory resorption develops, the tooth will be lost within a short time.

Treatment of mandibular fractures with rigid osteosynthesis: using the AO system

PURPOSE

This study evaluated the results achieved in the surgical treatment of all mandibular fractures at two university centers using the 2.7 AO mandibular system.

PATIENTS AND METHODS

A total of 227 patients presenting with 180 single fractures and 47 with double fractures (274 osteosyntheses) were included in this prospective study.

RESULTS

During a mean follow-up of 27.5 months (minimum, 12 months), an overall complication rate of 7% was observed. No infection justified early removal of the osteosynthesis material.

CONCLUSIONS

The systematic use of the technique recommended by AO for treating mandibular fractures, performed by thoroughly experienced operators on a compliant population, results in a low rate of complications and an early return to normal function.

Survival of avulsed permanent maxillary incisors in children following delayed replantation

The purpose of this study was to identify the variables that significantly influenced the survival of incisors replanted after extended extra-alveolar duration at The Hospital for Sick Children, Toronto, Canada, between June 1988 and December 1993. Survival analysis was used to identify variables that significantly influence the retention of replanted incisor teeth. Survival was defined as the time that elapsed between the replantation of an avulsed incisor and the time it was finally lost. Information on 9 variables was collected for 38 patients (25 males; 13 females) and 52 replanted permanent maxillary incisors. The mean extra-alveolar duration for the sample was 123 min. The mean follow-up interval was 942 days (range: 364-2126 days). Incisors replanted with open apices had a significantly decreased survival compared with teeth with mature apices (P = 0.04; relative risk 4.2). There was also a significant association between increased survival and obturation of the root canal with gutta-percha and sealer (P = 0.006; relative risk 10.0). A trend towards improved survival of replanted incisors was found for children older than 11 years old at the time of replantation (P = 0.09; relative risk 2.8). These results are consistent with previous studies and may assist clinicians and parents in the decision-making process associated with the management of avulsed teeth in children.

Paediatric dentistry avulsion: case reports

Children may present at a dental surgery for management of oro-facial injuries. Most general dental practitioners are able to handle straightforward cases but referral may be required for complex injuries. Successful healing following tooth avulsion depends on the amount of damage to teeth and supporting structures, emergency treatment, and follow-up treatment. All of these play a role in the long-term prognosis of avulsed teeth.

Growth considerations in planning treatment of avulsion in an adolescent

Reimplantation failure of avulsed anterior teeth in an adolescent patient requires removal of the attempted-reimplanted teeth and consideration of several restorative options. These options may include a removable partial denture, as well as a transitional bridge or permanent fixed prosthesis. In all cases, the potential effects of the adolescent's expected amount and directions of maxillary and mandibular growth must be considered. A case is presented examining how maxillary growth may affect the restorative treatment options for avulsed anterior teeth replacement for an adolescent boy. Unfortunately, the patient and family were unable to complete treatment due to financial considerations. Consequently, the case presented here is submitted as a treatment planning exercise.

Periodontal healing of extracted dogs' teeth air-dried for extended periods and soaked in various media

The aim of this study was to determine the periodontal healing of replanted dogs' teeth which, after extended extra-oral dry times, had been soaked in various media before replantation. Incisors and premolars of beagle dogs were root canal treated, extracted and bench dried. The teeth were grouped according to dry times of 30, 45 and 60 minutes. Each group of teeth was soaked in one of three media, Hank's balanced salt solution, ViaSpan (Belzer UW-CSS, Dupont Pharmaceuticals), or Conditioned Medium (supernatant of confluent culture of human gingival fibroblasts) for 30 minutes before replantation. Controls consisted of teeth extracted and replanted without drying on soaking (negative control), and bench-dried teeth replanted without soaking in the media (positive control). The dogs were killed 6 months after replantation of the teeth, which were prepared for histologic evaluation. Five microns cross-sections (every 70 microns) of the root and surrounding tissue were evaluated for healing/resorption according to Andreasen's criteria. The best healing occurred for the roots which had been immediately replanted. Healing in the positive control groups decreased with increased dry time. For the 30-minute dry time groups, soaking in media had no beneficial effect on periodontal healing compared with the controls. Soaking in ViaSpan resulted in an increased healing incidence for both the 45- and 60-minute bench-dried groups while soaking in the other media had no consistent beneficial effect. It appears from this study that an avulsed tooth that has been left dry for 30 minutes should be replanted immediately without soaking. However, teeth that have been dry for 45 or 60 minutes would benefit from soaking for 30 minutes in ViaSpan.

A triply avulsed tooth

Canada has a rich hockey tradition. Accordingly, Canadian dentists are well acquainted with tooth avulsion, although the emergence as the mouth guard as an essential component of protective sports equipment has reduced its incidence. Practitioners occasionally examine patients who have lost teeth as a result of accidents. In this unusual case, a patient's tooth was removed 3 times in 12 hours.

Investigation of lay knowledge of the management of avulsed permanent incisors

The prognosis of replanted avulsed permanent incisors depends largely on prompt and appropriate emergency management. The aim of this study was to investigate lay knowledge and attitudes in this respect. Postal questionnaires were sent to all physical education teachers, school nurses and secretaries, attendants in swimming baths and leisure centres and to 220 parents of teenage children in a defined area of North West England. The overall questionnaire response rate was 86.9%. Knowledge of methods of dealing with this problem was generally inadequate in both parents and the other groups. Although 53.6% of respondents claimed to have received first aid training only 3.1% could remember dental injuries being included. There was evidence that dental health education in this field can be effective, since the highest mean knowledge score was found in the 11.5% of respondents who recalled receiving advice from sources such as posters, magazines and newspapers. More than 80% of the respondents stated that they would not want to replant an avulsed incisor themselves, the main reason being lack of knowledge and training. It is suggested that there is a need for potentially effective dental health education in relation to this problem.

Revascularization of traumatized teeth assessed by laser Doppler flowmetry: case report

Infection of the pulp space in addition to the attachment damage of a traumatic injury to a tooth, results in serious complications and often tooth loss. Therefore, the prevention or treatment of root canal infection is a major consideration in these cases. In immature teeth, revascularization of a necrotic pulp is possible and highly desirable. Unfortunately, current sensitivity tests are poor indicators of revascularization, with the result that many pulps are removed unnecessarily. Laser Doppler flowmetry is an objective test of the presence of moving red blood cells within a tissue, which has been reported to be effective in the detection of tooth pulp vitality as well. A case is presented where an eight year old child severely luxated both maxillary central incisors. While only one of the incisors was weakly responsive to CO2 ice at 76 days after replantation, the laser Doppler flowmeter indicated that revascularization was occurring in both teeth at a much earlier time. Because of the laser Doppler readings, endodontic treatment was not initiated and the teeth developed normally.