Multimodal Imaging of Dental Pulp Healing Patterns Following Tooth Autotransplantation and Regenerative Endodontic Treatment.

INTRODUCTION: Understanding the healing process of dental pulp after tooth autotransplantation (TAT) and regenerative endodontic treatment (RET) of immature teeth is important both clinically and scientifically. This study aimed to characterize the pattern of dental pulp healing in human teeth that underwent TAT and RET using state-of-the-art imaging techniques. MATERIALS AND METHODS: This study examined 4 human teeth, 2 premolars that underwent TAT, and 2 central incisors that received RET. The premolars were extracted after 1 year (case 1) and 2 years (case 2) due to ankylosis, while the central incisors were extracted after 3 years (cases 3 and 4) for orthodontic reasons. Nanofocus x-ray computed tomography was used to image the samples before being processed for histological and immunohistochemical analysis. Laser scanning confocal second harmonic generation imaging (SHG) was used to examine the patterns of collagen deposition. A maturity-matched premolar was included as a negative control for the histological and SHG analysis. RESULTS: Analysis of the 4 cases revealed different patterns of dental pulp healing. Similarities were observed in the progressive obliteration of the root canal space. However, a striking loss of typical pulpal architecture was observed in the TAT cases, while a pulp-like tissue was observed in one of the RET cases. Odontoblast-like cells were observed in cases 1 and 3. CONCLUSIONS: This study provided insights into the patterns of dental pulp healing after TAT and RET. The SHG imaging sheds light on the patterns of collagen deposition during reparative dentin formation.

Long-term Outcome of Endodontically Treated Traumatized Immature Upper Incisors.

INTRODUCTION: In a growing child, preservation of traumatized immature permanent upper incisors is challenging. This study aimed to evaluate the long-term outcome of endodontically treated traumatized immature upper incisors and associated variables. METHODS: A total of 183 traumatized immature upper incisors treated with pulpotomy, apexification, or regenerative endodontic procedure (REP), with follow-up between 4 and 15 years, were assessed for presence of pulpal responses or periodontal/bone responses using standardized clinical and radiologic criteria. Logistic regression, including stage of root development, type and complexity of traumatic event, type of endodontic intervention, and history of orthodontic management, were used to estimate impact on tooth survival and occurrence of tissue responses. Study approved by Ethics Committee Research UZ/KU Leuven (S60597). RESULTS: After a median follow-up of 7.3 years (interquartile range, 6.1-9.2), 159 teeth (86.9%) were still functional. From these teeth, 58 (36.5%) developed tissue responses. This was significantly associated with stage of root development at moment of trauma (root length <¾) and type of endodontic intervention (REP presenting worst outcome). Tooth loss (24 teeth, 13.1%) occurred after a mean time span of 3.2 years (±1.5) and was significantly associated with type and complexity of the traumatic event and type of endodontic intervention, with apexification showing better results than REP (odds ratio, 0.30; 95% confidence interval, 0.11-0.79). CONCLUSIONS: A large number of endodontically treated traumatized immature teeth could be kept functional. Very immature teeth, teeth with periodontal tissue damage, and teeth treated with REP were at highest risk for an unfavorable outcome.

Is use of CBCT without proper training justified in paediatric dental traumatology? An exploratory study.

BACKGROUND: Proper skills in radiographic diagnosis are essential for optimal management of dental trauma. AIM: To assess diagnostic accuracy obtained by paediatric dentists using Cone Beam Computed Tomography (CBCT) without specific training and to compare this with their performance using intraoral radiographs. METHODS: Intraoral and CBCT images of 89 teeth, spread over twenty dental trauma cases were presented in random order to nine paediatric dentists. Diagnostic findings were compared with those of a benchmark reference. Sensitivity and specificity were calculated and compared using paired t-tests. RESULTS: Overall, observers' diagnostic performance was rather poor with significantly higher sensitivity when using 2D images (P = 0.017). Performance differed considerably according to the type of pathology. Using either imaging modality, sensitivity for diagnosing apical pathology and root fractures was high while the opposite was seen for inflammatory root resorption, root cracks and subluxations. Statistically significant differences between imaging modalities were seen for root fractures (P = 0.013) and apical pathology (P = 0.001), in favor of 3D, and for crown fractures (P = 0.009) in favor of 2D. CONCLUSION: Overall poor performance of paediatric dentists indicates that additional training in radiographic diagnosis is required. In order to justify the use of CBCT to increase diagnostic performance, proper training of the paediatric dentist is mandatory.

Does clinical experience with dental traumatology impact 2D and 3D radiodiagnostic performance in paediatric dentists? An exploratory study.

BACKGROUND: The aim of this study is to evaluate the impact of experience with traumatic dental injuries (TDI) on paediatric dentists' performance and self-assessed confidence when radiodiagnosing traumatic dental injuries (TDI) and to explore whether this is influenced by the imaging technique used (2D versus 3D). MATERIALS AND METHODS: Both 2D and 3D radiological images of young anterior permanent teeth having experienced dental trauma were assessed randomly by a panel of paediatric dentists using structured scoring sheets. The impact of level of experience with dental traumatology on radiological detection, identification and interpretation of lesions and on observer's self-assessed confidence was evaluated. Findings were compared to benchmark data deriving from expert consensus of an experienced paediatric endodontologist and dentomaxillofacial radiologist. Results were analysed using generalized linear mixed modelling. RESULTS: Overall, observers performed moderately to poor, irrespective of their level of TDI experience and imaging modality used. No proof could be yielded that paediatric dentists with high TDI experience performed better than those with low experience, for any of the outcomes and irrespective of the imaging modality used. When comparing the use of 3D images with 2D images, significantly higher sensitivities for the detection and correct identification of anomalies were observed in the low experienced group (P < 0.05). This was not the case regarding interpretation of the findings. Self-assessed confidence was significantly higher in more experienced dentists, both when using 2D and 3D images (P < 0.05). CONCLUSION: There was no proof that paediatric dentist's higher experience with TDI is associated with better radiodiagnostic performance. Neither could it be proven that the use of Cone Beam Computed Tomography (CBCT) contributes to an improved interpretation of findings, for any experience level. More experienced dentists feel more confident, irrespective of the imaging modality used, but this does not correlate with improved performance. The overall poor performance in image interpretation highlights the importance of teaching and training in both dental radiology and dental traumatology.

Regenerative Endodontic Procedure of Immature Permanent Teeth with Leukocyte and Platelet-rich Fibrin: A Multicenter Controlled Clinical Trial.

INTRODUCTION: The aim of this nonrandomized, multicenter controlled clinical trial was to evaluate the impact of leukocyte-platelet-rich fibrin (LPRF) on regenerative endodontic procedures (REPs) of immature permanent teeth in terms of periapical bone healing (PBH) and further root development (RD). METHODS: Healthy patients between 6-25 years with an inflamed or necrotic immature permanent tooth were included and divided between the test (= REP + LPRF) and control (= REP-LPRF) group depending on their compliance and the clinical setting (university hospital or private practice). After receiving REP ± LPRF, the patients were recalled after 3, 6, 12, 24, and 36 months. At each recall session, the teeth were clinically and radiographically (by means of a periapical radiograph [PR]) evaluated. A cone-beam computed tomographic (CBCT) imaging was taken preoperatively and 2 and 3 years postoperatively. PBH and RD were quantitatively and qualitatively assessed. RESULTS: Twenty-nine teeth with a necrotic pulp were included, from which 23 (9 test and 14 control) were analyzed. Three teeth in the test group had a flare-up reaction in the first year after REP. Except for 2 no shows, all the analyzed teeth survived up to 3 years after REP, and, in case of failure, apexification preserved them. Complete PBH was obtained in 91.3% and 87% of the cases based on PR qualitative and quantitative evaluation, respectively, with no significant difference between the groups with respect to the baseline. The PR quantitative change in RD at the last recall session with respect to the baseline was not significant (all P values > .05) in both groups. The qualitative assessment of the type of REP root healing was nonuniform. In the test group, 55.6% of the teeth presented no RD and no apical closure. Only 50% of the 14 teeth assessed with CBCT imaging presented complete PBH. Regarding volumetric measurements on RD 3 years after REP for the change with respect to the baseline in root hard tissue volume, mean root hard tissue thickness, and apical area, the control group performed significantly in favor of RD than the test group (P = .03, .003, and 0.05 respectively). For the volumetric change 3 years after REP with respect to the baseline in root length and maximum root hard tissue thickness, no significant difference (P = .72 and .4, respectively) was found between the groups. The correlation between the PR and CBCT variables assessing RD was weak (root lengthening) to very weak (root thickening). CONCLUSIONS: REP-LPRF seems to be a viable treatment option to obtain PBH and aid further RD of necrotic immature permanent teeth. Caution is needed when evaluating REP with PR.

Orthodontic treatment recommendation and expected adverse reactions in patients with a history of dental trauma: A survey among general dentists, paediatric dentists, and orthodontic specialists.

BACKGROUND: Trauma-induced adverse reactions may trigger complications when moving teeth orthodontically. AIM: The purpose of this study was to evaluate the knowledge of dental practitioners about this topic. DESIGN: A questionnaire survey was organized among general dentists, paediatric dentists, and orthodontists in Flanders (Belgium). Three clinical cases describing trauma-induced tooth damage (tooth ankylosis, apical root resorption, and pulp/root canal obliteration) were presented, followed by a set of questions. RESULTS: The questionnaire was completed by 121 general dentists (GD), 47 paediatric dentists (PD), and 99 orthodontic specialists (OS). In the case with ankylosis, impossibility to move the tooth orthodontically was reported as most frequent adverse reaction (82.8% of GD, 95.7% of PD, and 100.0% of OS) (P < .001). In the situation of apical root resorption, the most frequently reported adverse event was progressive apical root resorption (78.9%, 85.7%, and 88.8% respectively; P = .265). Most frequently mentioned adverse reaction in the case with pulp and root canal obliteration was tooth discoloration (64.1%, 57.1%, and 78.3%; P = .055), followed by apical root resorption (57.4%, 56.8%, and 68.7%; P = .283). Orthodontic treatment recommendation differed among specific clinical situations but also among groups of dental practitioners. CONCLUSIONS: Important knowledge gaps exist regarding the orthodontic managment of traumatized teeth. This topic requires more attention in undergraduate training, specialist training, and continuing education.

Bioactivity potential of Portland cement in regenerative endodontic procedures: From clinic to lab.

OBJECTIVE: The aim of this study was to evaluate the bioactivity potential of an hydraulic calcium-silicate cement, Pure Portland Cement Med-PZ (Medcem, Weinfelden, Switzerland: 'MPC'), applied in a tooth extracted because of failed regenerative endodontic procedures (REP) and by means of ex vivo (EV) specimens. METHODS: Ten EV cylindrical dentin cavities were prepared and filled with MPC and stored for 1 month in distilled water (DW), Hank's balanced salt solution (HBSS), Dulbecco's phosphate-buffered saline (DPBS), simulated body fluid (SBF), versus no media (NM) serving as control. Six additional EV specimens were filled with MPC and exposed for 2 weeks to leucocyte-and-platelet-rich fibrin (LPRF)-clot (C), LPRF-membrane (M) and LPRF-exudate (E). MPC in the EV specimens and in the coronal part of the REP tooth was analyzed by means of micro-Raman spectroscopy (MR), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). RESULTS: SEM showed rough crystallite surfaces for the EV samples and a porous surface for the REP tooth. EDS of the EV samples revealed prominent peaks for Ca, Si and O. Storage in HBSS, DPBS, SBF, exposure to LPRF and the REP tooth showed considerable amounts of P as well. MR exhibited vibrations of phosphate (DPBS, SBF), carbonated hydroxyapatite (DPBS, SBF), calcium carbonate (DW, HBSS, NM, REP-tooth, LPRF-E), oxidized (ferric) proteins (LPRF-E/C/M) and the amide III band (all samples). Hence, only storage of MPC in DPBS and SBF for 1 month revealed bioactivity. SIGNIFICANCE: The environmental conditions, namely the laboratory and clinical settings, affect the bioactivity potential of MPC.

Knowledge of orthodontic treatment approach of traumatized teeth by a group of Belgian general dentists, pediatric dentists, and orthodontists.

BACKGROUND/AIM: Traumatized teeth are more susceptible to complications during orthodontic tooth movement. The aim of this study was to explore current practices among Belgian dental practitioners regarding orthodontic treatment of children with a history of dental trauma. MATERIAL AND METHODS: A questionnaire survey was organized among general dentists, pediatric dentists, and orthodontists in Flanders (Belgium). Questionnaires were distributed at the occasions of annual meetings or symposia. They consisted of questions regarding exposure to dental trauma and orthodontic treatment approach for patients with a dental trauma history. RESULTS: The questionnaire was completed by 121 general dentists, 47 pediatric dentists, and 99 orthodontists. A history of dental trauma influenced referral for orthodontic treatment by general dentists and pediatric dentists moderately (median VAS scores of 5 and 6, respectively, on a scale of 0 (not at all) to 10 (utmost)), indicating uncertainty and doubt. Additional checkups during tooth movement were usually not organized by general dentists in 33.6% and by pediatric dentists in 19.1% of cases (P = 0.006). One-third of the orthodontists (33.3%) experienced tooth loss linked to orthodontic movement of a tooth with dental trauma history in at least one patient. Only a minority of the practitioners knew of the existence of specific guidelines (7.6%, 15.6% and 22.7%, respectively, of general dentists, pediatric dentists, and orthodontists) (P = 0.007). The Dental Trauma Guide was the guideline mentioned most frequently, although this tool does not contain recommendations regarding orthodontic treatment after trauma. CONCLUSION: In the group of Belgian general dental, pediatric and orthodontists surveyed, there was uncertainty regarding the orthodontic management of patients with a history of dental trauma especially among general practitioners. Further educational training is recommended.

Regenerative Endodontic Procedures Posttrauma: Immunohistologic Analysis of a Retrospective Series of Failed Cases.

INTRODUCTION: Regenerative endodontic procedures (REP) are a novel treatment modality to restore the function of necrotic pulp tissue via stimulation or transplantation of stem cells into the root canal. This study aimed to investigate the immunohistologic outcome of 3 extracted teeth because of sequelae of trauma and unsatisfactory REP outcomes. METHODS: Three immature permanent maxillary central incisors of 3 female patients (6-9 years) were extracted 5.5-22 months after REP. Additionally, 1 sound permanent immature central maxillary incisor of 1 of the included patients was extracted for orthodontic reasons. The teeth were immunohistologically stained with Masson's trichrome, neurofilament (NF), pan cytokeratin, dentin sialophosphoprotein, and Gram+/-. RESULTS: The REP-teeth presented intracanalar vascularized connective/mineralized reparative tissue (RT), which was less organized than the pulp tissue of the sound tooth. Moderate to considerable calcification was observed below the Portland cement used during REP. In 1 case, the RT was NF+; in the 2 other cases, the periodontal ligament and apical granuloma/papilla were NF+. All teeth were Gram+/- negative; nevertheless, inflammatory cells were present in 2 cases. The pan cytokeratin and dentin sialophosphoprotein stainings were not specific enough for 2 cases. CONCLUSIONS: This immunohistologic study of failed REP cases resulted in bacteria-free intracanalar RT and biomaterial-induced calcification. Nevertheless, the presence of inflammatory cells revealed a persistent inflammation. Hence, the clinical and radiographic signs were decisive for tooth survival and multidisciplinary outcome determination.

Regenerative endodontic procedure of an infected immature permanent human tooth: an immunohistological study.

OBJECTIVES: An immunohistological study of an infected immature permanent human tooth after a regenerative endodontic procedure (REP) was conducted in order to determine the histologic outcome of this procedure. Besides observed signs of angiogenesis and neurogenesis, repair and/or regeneration of the pulp-dentin complex was also investigated. MATERIALS AND METHODS: A REP was performed on tooth 45 of a 10-year-old girl. Eleven months post-treatment, the tooth had to be removed for orthodontic reasons. The following investigations were performed: immunohistology and radiographic quantification of root development. After hematoxylin-eosin (HE) staining, the following immunomarkers were selected: neurofilament (NF), pan cytokeratin (PK), osteocalcin (OC), and CD34. RESULTS: The REP resulted in clinical and radiographic healing of the periradicular lesion and quantifiable root development. The HE staining matches with the medical imaging post-REP: underneath the mineral trioxide aggregate a calcified bridge with cell inclusions, connective pulp-like tissue (PLT) with blood vessels, osteodentin against the root canal walls, on the root surface cementum (Ce), and periodontal ligament (PDL). The PDL was PK(+). The blood vessels in the PLT and PDL were CD34(+). The Ce, osteodentin, and stromal cells in the PLT were OC(+). The neurovascular bundles in the PLT were NF(+). CONCLUSIONS: Immunohistologically, REP of this infected immature permanent tooth resulted in an intracanalar connective tissue with a regulated physiology, but not pulp tissue. CLINICAL RELEVANCE: REP of an immature permanent infected tooth may heal the periapical infection and may result in a combination of regeneration and repair of the pulp-dentin complex.

3-dimensional analysis of regenerative endodontic treatment outcome.

INTRODUCTION: A growing body of evidence supports the regeneration potential of dental tissues after regenerative endodontic treatment (RET). Nevertheless, a standard method for the evaluation of RET outcome is lacking. The aim of this study was to develop a standardized quantitative method for RET outcome analysis based on cone-beam computed tomographic (CBCT) volumetric measurements. METHODS: Five human teeth embedded in mandibular bone samples were scanned using both an Accuitomo 170 CBCT machine (Morita, Kyoto, Japan) and a SkyScan 1174 micro-computed tomographic (µCT) system (SkyScan, Antwerp, Belgium). For subsequent clinical application, clinical data and low-dose CBCT scans (preoperatively and follow-up) from 5 immature permanent teeth treated with RET were retrieved. In vitro and clinical 3-dimensional image data sets were imported into a dedicated software tool. Two segmentation steps were applied to extract the teeth of interest from the surrounding tissue (livewire) and to separate tooth hard tissue and root canal space (level set methods). In vitro and clinical volumetric measurements were assessed separately for differences using Wilcoxon matched pairs test. Pearson correlation analysis and Bland-Altman plots were used to evaluate the relation and agreement between the segmented CBCT and µCT volumes. RESULTS: The results showed no statistical differences and strong agreement between CBCT and µCT volumetric measurements. Volumetric comparison of the root hard tissue showed significant hard tissue formation. (The mean volume of newly formed hard tissue was 27.9 [±10.5] mm(3) [P < .05]). CONCLUSIONS: Analysis of 3-dimensional data for teeth treated with RET offers valuable insights into the treatment outcome and patterns of hard tissue formation.