Damage of the Hertwig's epithelial root sheath: effect upon root growth after autotransplantation of teeth in monkeys

Micro-CT Evaluation of Spontaneous Apexification of an Immature Tooth following Trauma

This case reports on the micro-computerised tomography (CT) images of a periapical calcified dome following spontaneous apexification as a subsequence of trauma. An immature, maxillary central incisor was found to be non-vital one month following trauma. The tooth had minimal signs of structural damage; however, there was radiographic evidence of spontaneous apexification. The tooth suffered a second traumatic episode two years later and was decoronated to facilitate bone retention during osseous development. The patient presented with swelling and pain 36 months later, and the tooth root was extracted. The root was embedded in resin, and cross-sectional images were obtained using micro-CT. Analysis of the images provided insight into the structure of the calcified dome that formed following the first traumatic injury.

Effect of systemic antibiotic therapy on pulp repair following extrusive luxation and avulsion in a murine model: A histomorphological study

BACKGROUND/AIM

The evidence for any benefit of systemic antibiotic therapy on pulp survival following extrusive luxation and avulsion is inconclusive. The aim of this study was to evaluate the effect of systemic antibiotic therapy with amoxycillin and tetracycline for 7 days on different aspects of dental pulp repair in a murine model.

MATERIAL AND METHODS

The right maxillary incisor of 180 4 to 8-week-old male Wistar rats underwent extrusive luxation or avulsion. The animals were then treated with saline solution (control), tetracycline, or amoxicillin administered intra-gastrically for 7 days, and euthanized at 7, 15, and 30 days post-operatively. The layer of odontoblast cells, reparative dentin deposition, Hertwig's epithelial root sheath, pulp necrosis, and periapical inflammatory infiltrate were histomorphologically analyzed and scored. Mann-Whitney, Kruskal-Wallis, and Dunn tests were used to compare mean scores for the different procedures, treatments, and times (p ≤ .05).

RESULTS

Significant differences were observed between luxated and avulsed teeth (p < .05). In luxated teeth, no differences were observed among treatments and times, except for more tertiary dentin deposition in the coronal third with the use of tetracycline compared with amoxicillin at 15 days (p < .05). In avulsed teeth, higher scores for the layer of odontoblast cells and lower scores for periapical inflammatory infiltrate at 7 days and pulp necrosis at 7 and 15 days were observed in the amoxicillin group compared to the saline and tetracycline groups (p < .05). At 30 days, however, no differences were observed among treatments.

CONCLUSIONS

The use of systemic antibiotic therapy with tetracycline or amoxicillin for 7 days did not contribute to pulp repair following extrusive luxation or avulsion in rats. However, the results warrant further research into the use of amoxicillin for a more extended period of time in cases of avulsion.

The enhanced conservation of vital pulp and apical tissues by the application of crown rotation surgery for inversely impacted central incisors: a follow-up analysis of two patients over four years

AIM

To describe a novel surgical method (crown rotation surgery) to manage inversely impacted central incisors with immature roots.

SUMMARY

Two young patients each presented with an inversely impacted maxillary central incisor. To protect the apical tissues, the two impacted incisors were rotated downwards to a relatively normal position without extraction from their bony sockets. After crown rotation surgery, spontaneous eruption, continuous root development, and periodontal healing of the rotated incisors were observed. The pulp retained vitality and blood flow was normal. Moreover, there were no obvious signs of pulp canal obliteration (PCO), as indicated by Cone Beam Computed Tomography (CBCT) imaging.

KEY LEARNING POINTS

• By optimising protection of the vital pulp and apical tissues, crown rotation surgery represents a minimally invasive, conservative, and practical surgical technique for treating inversely impacted incisors with developing roots. • In contrast to existing surgical methods, crown rotation surgery may avoid certain complications, including PCO and abnormal or arrested root development.

Influence of Static Navigation Technique on the Accuracy of Autotransplanted Teeth in Surgically Created Sockets

The aim of this study was to analyse and compare the position of single-rooted autotransplanted teeth using computer-aided SNT drilling and conventional freehand (FT) drilling, by comparing the planned and performed position at the coronal, apical and angular level. Materials and methods: Forty single-root upper teeth were selected and distributed into the following study groups: A. Autotransplanted tooth using the computer-aided static navigation technique (SNT) (n = 20) and B. Autotransplanted tooth using the conventional free-hand technique (FT) (n = 20). Afterwards, the teeth were embedded into two experimental models and 10 single-root upper teeth were randomly autotransplanted in each experimental model. The experimental models were submitted to a preoperative cone-beam computed tomography (CBCT) scan and a digital impression by a 3D intraoral scan, in addition to a postoperative CBCT scan, after the autotransplantation. Datasets from postoperative CBCT scans of the two study groups were uploaded to the 3D implant planning software, aligned with the autotransplantation planning, and the coronal, apical and angular deviations were measured. The results were analysed using Student’s t-test and Mann–Whitney non-parametric statistical analysis. Results: Coronal (p = 0.079) and angular (p = 0.208) statistical comparisons did not present statistically significant differences; however, statistically significant differences between the apical deviation of the SNT and FT study groups (p = 0.038) were also observed. Conclusions: The computer-aided static navigation technique does not provide higher accuracy in the positioning of single-root autotransplanted teeth compared to the conventional free-hand technique.

Ingrowth of Mineralized Tissue into the Root Canal of Immature Permanent Teeth after a Traumatic Injury: A Report of 3 Cases

The aim of this case series was to describe the endodontic management of 3 immature permanent teeth that sustained traumatic injuries and subsequently presented with complete ingrowth of mineralized tissue into the canal space. Ingrowth of bone/mineralized tissue into the canal has been considered a poor long-term outcome with an inherent risk of ankylosis. In cases 1 and 2, no endodontic treatment was undertaken, except for emergency management requiring splinting. The cases were followed for 36 and 23 months, respectively. No ankylosis was evident over the review period, and normal teeth eruption was apparent. In case 1, the tooth was treated orthodontically and was responsive to pulp sensibility testing. In both cases, there was an appearance of an internal periodontal ligament-like space on the inner root wall of the canal. In case 3, 2 years postinjury, pulp necrosis and apical periodontitis occurred, and the tooth was managed with regenerative endodontic treatment consistent with the European Society of Endodontology and the American Association of Endodontists guidelines/recommendations for a regenerative procedure. The case was followed for 8 years after regenerative endodontic treatment. No ankylosis was noted with normal eruption of the teeth. The tooth was responsive to pulp sensibility testing despite the ingrowth of mineralized tissue, which was confirmed clinically.

Roles of Dental Mesenchymal Stem Cells in the Management of Immature Necrotic Permanent Teeth

Dental caries and trauma always lead to pulp necrosis and subsequent root development arrest of young permanent teeth. The traditional treatment, apexification, with the absence of further root formation, results in abnormal root morphology and compromises long-term prognosis. Regeneration endodontics procedures (REPs) have been developed and considered as an alternative strategy for management of immature permanent teeth with pulpal necrosis, including cell-free and cell-based REPs. Cell-free REPs, including revascularization and cell homing with molecules recruiting endogenous mesenchymal stem cells (MSCs), have been widely applied in clinical treatment, showing optimistic periapical lesion healing and continued root development. However, the regenerated pulp-dentin complex is still absent in these cases. Dental MSCs, as one of the essentials of tissue engineering, are vital seed cells in regenerative medicine. Dental MSC-based REPs have presented promising potential with pulp-dentin regeneration in large animal studies and clinical trials via cell transplantation. In the present review, we summarize current understanding of the biological basis of clinical treatments for immature necrotic permanent teeth and the roles of dental MSCs during this process and update the progress of MSC-based REPs in the administration of immature necrotic permanent teeth.

Guided tooth autotransplantation in edentulous areas post-orthodontic treatment

OBJECTIVE

Tooth autotransplantation with a complete root formation to replace one or more lost teeth is indicated as a cost-effective alternative to implants. The aim of this case report was to describe a successfully guided autotransplantation of a maxillary third molar with fully formed roots into a surgically created socket after orthodontic space opening.

CLINICAL CONSIDERATIONS

A guided autotransplantation of the maxillary left third molar into the missing maxillary left first molar site was chosen. After virtually orientating donor tooth to confirm its optimum fit, it was deemed necessary to open 4 mm the mesiodistal space. Following the orthodontic movement, a 3-dimensional (3D)-guiding template and a milled surgical guide were manufactured to allow the donor tooth to be transplanted exactly in the planned position. The 2-year follow-up periapical radiograph showed a continuous periodontal space with no signs of apical periodontitis or root resorption.

CONCLUSIONS

Virtual planning and 3D-printed tooth replica combined with guided surgery can simplify the autotransplantation technique for both the clinician and the patient, particularly when the socket has been completely created during surgery.

CLINICAL SIGNIFICANCE

Virtual digital planning, which can accurately calculate the exact space to open orthodontically before an autotransplantation, could prove essential to enhancing the precision of 3D placement of the donor tooth in the recipient site.

Use of computer-aided three-dimensional prototyping to surgically assist in tooth autotransplantation

Autotransplantation is a surgical technique in which a donor tooth belonging to the same individual is repositioned into a surgically prepared socket or site of previous tooth extraction. It is beneficial in patients with teeth affected by agenesis, trauma, significant caries, and in teeth in a non-restorable condition or prognostically poor due to other pathology. It is particularly useful in paediatric patients, as properly transplanted teeth have a vital periodontium that allows for continuous growth and functional adaptation leading to preservation of the alveolar ridge. Technological advances in rapid prototyping combined with three-dimensional (3D) computed tomography (CT) have the ability to revolutionise autotransplantation. Preoperative planning for atraumatic extraction of the donor tooth and precise preparation of the recipient site with a rapid prototyped surgical template of the donor tooth considerably reduces the extra-alveolar time, and also reduces manipulation of the root sheath and periodontal ligament, and related trauma. This case series demonstrates the efficient and successful autotransplantation of various types of teeth with the use of a rapid prototyped surgical template produced from 3D CT. The use of this technology is expected to refine the surgical technique and improve treatment outcomes.

Clinical cell-based versus cell-free regenerative endodontics: clarification of concept and term

There is no consensus on the true meaning of clinical regenerative endodontics, and there is confusion over the concept and the term. Commonly used terms include revitalization and revascularization. The clinical methods for endodontic revitalization procedures and the tissue engineering concept differ depending on whether there is exogenous delivery of cells - called cell therapy, or not. Here, in this review, the difference is clarified by emphasizing the correct terminology: cell-free versus cell-based regenerative endodontic therapy (CF-RET versus CB-RET). The revitalization procedures practised clinically do not fit into the modern tissue engineering concepts of pulp regeneration but can be categorized as CF-RET. The modern tissue engineering concept in pulp regeneration is a CB-RET, which so far is at the clinical trial stage. However, histological examination of teeth following regenerative endodontic treatments reveals healing with repair derived from stem cells that originate from the periodontal, bone and other tissues. The aim of regenerative endodontics is regeneration of the pulp-dentine complex. This review discusses why CF-RET is unlikely to regenerate a pulp-dentine complex with current protocols. The American Association of Endodontists and the European Society of Endodontology have not yet recommended autologous stem cell transplantation (CB-RERT) which aspires for regeneration. Therefore, an understanding of the concept, term, difficulties and differences in current protocols is important for the clinician. However, rather than being discouraged that ideal regeneration has not been achieved to date, repair can be an acceptable outcome in clinical regenerative endodontics as it has also been accepted in medicine. Repair should also be considered in the context that resolution of the clinical signs/symptoms of pulp necrosis/apical periodontitis is generally reliably obtained in clinical regenerative endodontics.

Long-term follow-up of traumatized immature necrotic permanent teeth treated with regenerative endodontic protocol using platelet-rich fibrin: A prospective case series

The purpose of this prospective case series was to report the long-term clinical and radiographic outcomes of regenerative endodontic procedures (REP) using platelet-rich fibrin (PRF), in traumatized immature permanent teeth with necrotic pulps. Six immature necrotic permanent maxillary central incisors from six patients were treated with REP supplemented with PRF. Patients were recalled at 6, 12, 18, 24, 36, 48, and 60 months. Radiographic changes in the radiographic root area (RRA), apical diameter, root thickness, and root length were quantified. Clinically, tooth survival in terms of tooth retention in the arch and absence of any sign and symptoms of endodontic pathology were noted. All the teeth survived and met the clinical criteria for success throughout the follow-up period. Follow-up radiographs at 5 years revealed complete resolution of the periapical lesions in all patients and the average apical diameter decrease was 30.96%. An average increase of 13.18% for root length, 40.20% for root thickness, and 26.35% for RRA were noted.

Effect of Root Canal Therapy on the Success Rate of Teeth with Complete Roots in Autogenous Tooth Transplantation

BACKGROUND

Autogenous tooth transplantation is a reliable method for repairing missing teeth. Although it recently became a recognized and feasible treatment method in dentistry, the long-term efficacy of root canal therapy (RCT) has not been well confirmed. This study is aimed at determining whether RCT has a good effect on the success rate of teeth with complete roots in autogenous tooth transplantation.

MATERIALS AND METHODS

Data were collected from the Korea University Guro Hospital. Data of patients who underwent autogenous tooth transplantation within 9 years were collected. We selected 29 teeth with complete roots as the research subjects in our study. None of the patients had any systemic diseases. All cases in this study were obtained with patient permission.

RESULTS

According to the tooth vitality test, the autogenous teeth tested negative in dental pulp test and function. Nine of the 29 teeth with autogenous tooth transplantation were treated with RCT and survived throughout the observation period. However, 20 autogenous teeth were not treated with RCT, and eight of them did not survive. All statistical analyses were performed using IBM SPSS 20.0. The null hypothesis was rejected (p < 0.05).

CONCLUSION

For complete root teeth, the success rate after autogenous tooth transplantation after RCT is higher than that of teeth not treated with RCT.

Effect of orthodontic forces on root length of immature mandibular second premolars: a split-mouth randomized clinical trial

Objective:

To assess the effect of orthodontic forces on changes in root length of immature mandibular second premolars.

Methods:

Sixty-four mandibular second premolars (MSP) with immature apices (left and right sides) of 32 patients aged between 10 and 13 years were evaluated. Orthodontic treatment was started after obtaining periapical radiographs (T₁) from the MSPs of each patient. Brackets were bonded, except the ones of MSPs (left or right by random as control MSP, and the other side as test MSP). After 9-12 months, a second periapical radiograph (T₂) was obtained from the MSPs of each patient. Then, brackets were bonded to the control MSPs, which were not bonded before. After 18 ± 3 months, a third periapical radiograph (T₃) was obtained. Changes in root length were evaluated by using a new formula. The test and control MSPs at T₁, T₂ and T₃ were compared using repeated measures ANOVA and parametric tests. P-value smaller than 0.05 was statistically significant.

Results:

There was no significant difference between the test and control groups in the mean root length of MSP at T₁ (p= 0.48) and T₃ (p= 0.078). The root length at T₂ (p= 0.001) was significantly different between test and control MSPs, and the test group showed longer root length than the control group.

Conclusions:

Orthodontic force applied for leveling and alignment of immature MSPs may not have destructive effects on the roots, and may accelerates root formation in short-term. Normal root length was achieved at the end of root development.

Impact of remnant healthy pulp and apical tissue on outcomes after simulated regenerative endodontic procedure in rat molars

When regenerative endodontic procedures (REPs) are performed on immature teeth diagnosed with pulp necrosis and apical periodontitis, various healing patterns occur. Furthermore, infected immature teeth with endodontic disorders often exhibit some remnant pulp and apical tissue. Therefore, this study investigated the impact of remnant healthy or fully functional pulp and apical tissue on healing patterns after REPs. Simulated REPs were performed on non-infected immature rat molars with different amounts of remnant pulp and apical tissue. Healing patterns in these teeth were assessed after 28 days. Teeth with 0.81–0.91 mm of remnant pulp healed with pulp-like tissue, dentin, and osteodentin-like dentin-associated mineralized tissue (OSD-DAMT); teeth with 0.60–0.63 mm of remnant pulp healed with pulp-like tissue and OSD-DAMT; teeth with 0.13–0.43 mm of remnant pulp healed with periodontal ligament (PDL)-like tissue, OSD-DAMT, and cementum-like dentin-associated mineralized tissue (CEM-DAMT); and teeth with disorganization of pulp and apical tissues at 0.15–0.38 mm beyond the root apex healed with PDL-like tissue, CEM-DAMT, and intracanal bone (IB). Loss of Hertwig’s epithelial root sheath was observed with IB formation. These results showed that four distinct healing patterns occurred after REPs, depending on the preoperative amount of remnant healthy pulp and apical tissue.

Regenerative endodontic therapy (RET) for managing immature non-vital teeth: experiences and opinions of paediatric dental practitioners in the European and Arabian regions

PURPOSE

MTA apical plug approach is considered the gold standard in managing immature teeth with necrotic pulp tissues but does not increase root dimensions. Regenerative Endodontic Therapy (RET) has been advocated as an alternative technique for management of these teeth. This study aimed to assess the knowledge, experience and the opinions of dentists treating paediatric patients in the European and Arabian regions on RET.

METHODS

A cross-sectional, pre-piloted 23-item self-administered questionnaire survey was distributed electronically using the Bristol Online Survey tool through the mailing list of the European Academy of Paediatric Dentistry, the Arabian Academy of Paediatric Dentistry's and the Egyptian Society of Paediatric Dentistry.

RESULTS

308 respondents completed the survey. Approximately half practised RET (N = 158; 51.3%), which was most frequently used to manage non-vital traumatized teeth. Majority of RET practitioners worked in university or dental institute practices. Protocol differences with deviation from the current published RET guidelines were observed. Half of the respondents reported discolouration as an undesirable outcome. Lack of training, materials, evidence and suitable cases were reasons for not using RET.

CONCLUSIONS

Although RET is being practised by European and Arabian paediatric dentists, different protocols are being used with clear deviations from the current evidence-based guidelines.

Application of Platelet-Rich Fibrin as Regeneration Assistant in Immediate Auototransplantation of Third Molar with Unformed Roots: Case Report and Review of Literature

Background

Autogenous Tooth Transplantation (ATT) is the surgical movement of a maturely or immaturely formed tooth from its original site to another extraction site or a surgically prepared socket in the same individual. The most important factor in the healing process after autotransplantation is the presence of intact and viable periodontal ligament cells, which have the ability to differentiate into osteoblasts and able to induce bone production. ATT can successfully replace removable dentures as a restoration option in a growing patient, while implants can be placed only after skeletal maturity is attained. Case Presentation. In this case, we presented an immediate ATT of the third molar with unformed roots to the extraction socket of the first molar with evidence of continued root formation after 2 years of follow-up.

Conclusion

Platelet-Rich Fibrin (PRF) can induce sustainable and accelerated healing, and it can also induce the regeneration process of the periodontal tissues and pulpal formation. This process plays a key role in future root development and success rate.

Orthodontic management of patients with congenitally missing permanent teeth

Dental agenesis is one of the most common developmental anomalies in humans. It occurs as part of a genetic syndrome or as an isolated sporadic or familial finding. Third molars, second mandibular premolars and maxillary lateral incisors are the most frequently targeted teeth of the permanent dentition. Clinically, patients with congenitally missing permanent teeth seeking treatment present with unesthetic diastemas, midline deviation and tilting of adjacent teeth in the edentulous areas. The impact of tooth agenesis reflects on esthetics, function, psychological and social well-being of the individuals affected. Orthodontics can contribute to the treatment plan selected by rearranging the present teeth so as to open spaces for prosthetic restorations or close spaces by reshaping teeth if needed. Following orthodontic space opening/maintaining, the usual alternatives involve single implants, two-(cantilever) or full coverage(cantilever) prostheses. Less frequently, the treatment modality of autotransplantation is proposed with a good esthetic result but feasible only in young patients where the roots of the premolars are still developing. In orthodontic space closure, treatment is accomplished sooner without waiting for the completion of growth of the patient. Depending on various factors such as the malocclusion, the dento-skeletal profile, the smile line, the space requirements, the teeth missing, the periodontal issues, the age of the patient and any financial issues, the clinician will determine the most appropriate treatment approach. The final esthetic and functional result should resemble an intact natural dentition.

Modified Apexification Procedure for Immature Permanent Teeth with a Necrotic Pulp/Apical Periodontitis: A Case Series

The current American Association of Endodontists clinical considerations for a regenerative endodontic procedure state that a regenerative procedure is suitable for immature permanent teeth with necrotic pulp when the pulp space is not needed for a post/core in the final restoration. Therefore, many immature permanent teeth with necrotic pulp that have sustained a substantial loss of coronal tooth structure either from caries or trauma are treated by apexification or mineral trioxide aggregate/Biodentine (Septodent, Lancaster, PA) apical barrier techniques in which no further root maturation would occur. This case series presents 10 immature permanent teeth with necrotic pulp in which a post/core was likely required in the future for adequate coronal restoration because of loss of substantial coronal tooth structure and a modified apexification procedure was used. All 10 cases after the modified apexification procedure showed no clinical symptoms/signs and showed radiographic evidence of healed/healing of periapical lesion after a 2-year review. Eight cases showed increased thickness of the apical root canal walls, increased apical root length, and apical closure. The overall percentage change in root length was 7.52%, in root width at the apical one third it was 18.89%, and in radiographic root area it was 15.04% at the 24- to 72-month follow-up period. This modified apexification procedure allows for the tooth to be restored with a post/core if required for the final restoration in the future as well as continued root development.

Autotransplantation in combination with orthodontic treatment

INTRODUCTION

Autotransplantation is a surgical method in which a tooth is repositioned within the same patient. It can be described as a controlled reimplantation of an extracted tooth into a new, surgically prepared socket. The key to success of this treatment is the preservation and regeneration of the periodontal ligament. It is an underutilized technique which, if conducted with a multidisciplinary team, can be an ideal treatment option for patients with failing or missing teeth.

OBJECTIVES

The detailed clinical procedures, indications for this technique, and the factors affecting its success are discussed.

Root Elongation After Autotransplantation in 58 Transplanted Premolars: The Radiographic Width of the Apex as a Predictor

PURPOSE

Autotransplantation of premolars with incomplete root development is a reliable treatment option for tooth replacement. Nevertheless, little is known about root development after transplantation of teeth. The aim of this study was to evaluate preoperative root development stage and radiographic width of the apex as predictors for root elongation after autotransplantation.

MATERIALS AND METHODS

A retrospective cohort study was implemented and composed of patients who underwent autotransplantation of at least 1 premolar. Using panoramic radiographs (orthopantomograms), calibrated measurements were taken to record the root development stage of the donor tooth, width of the apex, and root length of the transplanted tooth.

RESULTS

Forty-five patients (58 transplants) were included. Mean follow-up time was 12 months (range, 4 to 26 months). Fifty-three transplanted teeth (91.4%) showed root elongation. Mean root elongation at end of follow-up was 1.9 mm (range, 0.0 to 4.3 mm). A wide-open apex before transplantation was significantly associated with root elongation after autotransplantation (P < .01). Root development stage (P = .82) did not show significant associations with root elongation.

CONCLUSIONS

A wide-open apex (>2.0 mm) is an important predictor of root elongation after autotransplantation of premolars. This might be a better predictor for root development than preoperative root development stage.

Orthodontic Movement after Regenerative Endodontic Procedure: Case Report and Long-term Observations

INTRODUCTION

Although regenerative treatment approaches in teeth with incomplete root formation and pulp necrosis have become part of the suggested therapeutic endodontic spectrum, little is known about the effect of orthodontic movement in the tissue that has been regenerated. Furthermore, as the number of adults undergoing orthodontic treatment increases, there is an increasing need to investigate the changes that these tissues may undergo during orthodontic movement. Here we describe the alterations observed after the application of orthodontic forces in a case of an apically root-fractured necrotic immature root that had been managed with regenerative endodontic procedures in the past.

METHODS

A 9-year-old male patient was referred after suffering the third incidence of trauma in the anterior maxilla. Radiographic evaluation revealed a periapical rarefaction associated with an apically root-fractured immature central incisor. Clinical evaluation revealed a buccal abscess and grade 3 tooth mobility. Periodontal probing was within normal limits. The tooth was accessed and disinfected by using apical negative pressure irrigation of 6% NaOCl. Intracanal dentin conditioning was achieved by using 17% EDTA for 5 minutes. A blood clot was induced from the periapical area, and calcium silicate-based cement was placed in direct contact with the blood clot at the same visit. The composite resin restoration was accomplished in the same appointment.

RESULTS AND CONCLUSIONS

Recall radiographic examination after 24 months revealed healing of the periapical lesion and signs of continuous root development despite the apical root fracture. Clinical evaluation revealed normal tooth development, normal mobility, and a resolving buccal infection. The tooth was subjected to orthodontic treatment because of Class II division 1 malocclusion with an overjet of 11 mm. After completion of the orthodontic treatment, 5.5 years after the initial intervention, the radiographic image revealed marked remodeling of the periapical tissues and repair of the apical fractures, and the buccal infection had resolved completely.

Regenerative Endodontic Therapy in the Management of Nonvital Immature Permanent Teeth: A Systematic Review-Outcome Evaluation and Meta-analysis

INTRODUCTION

Although the protocols in previously published studies appeared to be largely similar, there were inadequate evidence-based guidelines to support a single protocol. Using a meta-analysis, this systematic review aimed to summarize and quantitatively evaluate the outcomes for nonvital immature permanent teeth treated using the regenerative endodontic technique (RET) as well as critically appraise the level and quality of evidence of the existing publications.

METHODS

Risk of bias assessment and level of evidence grading were performed on all included studies. Meta-analyses using a random effects model were performed to combine the results of randomized controlled trials. The pooled success rate for each exposure was estimated for each outcome (event rates with 95% confidence intervals). The outcomes of all included studies were summarized.

RESULTS

Success rates for tooth survival and resolution of periapical pathosis were excellent; however, results for apical closure and continued root development were inconsistent. There are few well-reported randomized prospective clinical studies. Reporting of long-term outcomes and late-stage effects was sparse. No study evaluated health economic outcomes and improvements to patients' quality of life.

CONCLUSIONS

Many knowledge gaps still exist within the studies published. Current published evidence is unable to provide definitive conclusions on the predictability of RET outcomes.

Unusual root development following surgical repositioning of horizontally developing central incisor

Dilaceration is one of the causes of maxillary central incisor eruption failure. If the dilacerated maxillary permanent central incisor is in a horizontal or vertical position and root formation is in early stages, surgical repositioning is frequently the treatment of choice. In this article, the case of a horizontally impacted and dilacerated maxillary central incisor is presented which was treated by surgical repositioning. The tooth developed an unusual form of the root with discontinuity at the middle third region with the coronal and apical parts growing separately. Radiographic and clinical monitoring of the case was regularly performed. The tooth completely erupted in 2 years after the repositioning and even after 6 years of surgery is currently successfully functional in the arch with the malformed root. This article highlights the ability of Hertwig's epithelial root sheath to withstand trauma and its ability to recover.

Radiographic and clinical outcomes of the treatment of immature permanent teeth by revascularization or apexification: a pilot retrospective cohort study

INTRODUCTION

This retrospective cohort study compared clinical and radiographic outcomes of endodontic treatment performed in immature nonvital permanent teeth by apexification (calcium hydroxide or apical barrier with mineral trioxide aggregate) versus revascularization.

METHODS

A comprehensive chart review was performed to obtain a cohort of previously completed cases with recalls. Clinical and radiographic data were collected for 31 treated teeth (19 revascularization and 12 apexification) with an average follow-up time of 17 months and a recall rate of 63%. Tooth survival, success rate, and adverse events were analyzed. Changes in radiographic root length, width, and area were quantified.

RESULTS

The majority of treated teeth survived throughout the study period, with 30 of 31 (97%) teeth surviving (18/19 [95%] revascularization and 12/12 apexification). Most cases were also clinically successful, with 27 of 31 (87%) meeting criteria for success (15/19 [78%] revascularization and 12/12 apexification; nonsignificant difference). A greater incidence of adverse events was observed in the revascularization group (8/19 [42%] vs 1/12 [11%] in apexification) (risk ratio = 5.1; P = .04; 95% confidence interval, 0.719-35.48). Although more revascularization cases than apexification cases showed an increase in radiographic root area and width, the effect was not statistically significant.

CONCLUSIONS

In this study, revascularization was not superior to other apexification techniques in either clinical or radiographic outcomes. Studies with large subject cohorts and long follow-up periods are needed to evaluate outcomes of revascularization and apexification while accounting for important covariants relevant to clinical success.

A histological and micro-CT investigation in to the effect of NGF and EGF on the periodontal, alveolar bone, root and pulpal healing of replanted molars in a rat model - a pilot study

BACKGROUND

This study aims to investigate, utilising micro-computed tomography (micro-CT) and histology, whether the topical application of nerve growth factor (NGF) and/or epidermal growth factor (EGF) can enhance periodontal, alveolar bone, root and pulpal tissue regeneration while minimising the risk of pulpal necrosis, root resorption and ankylosis of replanted molars in a rat model.

METHODS

Twelve four-week-old male Sprague-Dawley rats were divided into four groups: sham, collagen, EGF and NGF. The maxillary right first molar was elevated and replanted with or without a collagen membrane impregnated with either the growth factors EGF or NGF, or a saline solution. Four weeks after replantation, the animals were sacrificed and the posterior maxilla was assessed using histological and micro-CT analysis. The maxillary left first molar served as the control for the corresponding right first molar.

RESULTS

Micro-CT analysis revealed a tendency for all replanted molars to have reduced root length, root volume, alveolar bone height and inter-radicular alveolar bone volume. It appears that the use of the collagen membrane had a negative effect while no positive effect was noted with the incorporation of EGF or NGF. Histologically, the incorporation of the collagen membrane was found to negatively affect pulpal, root, periodontal and alveolar bone healing with pulpal inflammation and hard tissue formation, extensive root resorption and alveolar bone fragmentation. The incorporation of EGF and NGF did not improve root, periodontal or alveolar bone healing. However, EGF was found to improve pulp vascularisation while NGF-improved pulpal architecture and cell organisation, although not to the level of the control group.

CONCLUSIONS

Results indicate a possible benefit on pulpal vascularisation and pulpal cell organisation following the incorporation of EGF and NGF, respectively, into the alveolar socket of replanted molars in the rat model. No potential benefit of EGF and NGF was detected in periodontal or root healing, while the use of a collagen membrane carrier was found to have a negative effect on the healing response.

Bone-like material growth in a replanted immature central incisor following avulsion

BACKGROUND

Avulsion is one of the most complicated types of trauma to the teeth. After replantation of an avulsed immature tooth, numerous pulpo-dentinal responses may occur.

CASE REPORT

This study reports a case of a seven-and-a-half-year-old boy in whom an immature maxillary permanent central incisor was replanted following avulsion due to a fall from a tree, and a bone-like growth was observed in the pulp chamber 6 months after the trauma, with a thin radiolucent line on the inner surface of the dentinal walls. The bone-like structure eventually filled the pulp chamber of the tooth.

FOLLOW-UP

The tooth was followed up 4 years after the replantation with no evidence of pathology.

CONCLUSION

This case demonstrates an immature avulsed tooth which did not present positive vital signs, but still maintains the potential of survival, and endodontic intervention may not be required. Instead, follow-up visits are recommended as long as there are no pathologic signs, especially in teeth with questionable prognosis.

Revascularization: a treatment for permanent teeth with necrotic pulp and incomplete root development

INTRODUCTION

Endodontic treatment of immature permanent teeth with necrotic pulp, with or without apical pathosis, poses several clinical challenges. There is a risk of inducing a dentin wall fracture or extending gutta-percha into the periapical tissue during compaction of the root canal filling. Although the use of calcium hydroxide apexification techniques or the placement of mineral trioxide aggregate as an apical stop has the potential to minimize apical extrusion of filling material, they do little in adding strength to the dentin walls. It is a well-established fact that in reimplanted avulsed immature teeth, revascularization of the pulp followed by continued root development can occur under ideal circumstances. At one time it was believed that revascularization was not possible in immature permanent teeth that were infected.

METHODS

An in-depth search of the literature was undertaken to review articles concerned with regenerative procedures and revascularization and to glean recommendations regarding the indications, preferred medications, and methods of treatment currently practiced.

RESULTS

Disinfection of the root canal and stimulation of residual stem cells can induce formation of new hard tissue on the existing dentin wall and continued root development.

CONCLUSIONS

Although the outcome of revascularization procedures remains somewhat unpredictable and the clinical management of these teeth is challenging, when successful, they are an improvement to treatment protocols that leave the roots short and the walls of the root canal thin and prone to fracture. They also leave the door open to other methods of treatment in addition to extraction, when they fail to achieve the desired result.