Evaluation of stress distributions in endodontically treated anterior incisors under occlusal and trauma-induced forces following various restoration treatments: A finite element analysis.

BACKGROUND: The aim of this study was to calculate the stress distribution of fiberglass post associated with resin composite crown restoration and fiberglass posts with zirconia restorations in mature and immature endodontically treated central maxillary incisor under various loading conditions. MATERIALS AND METHODS: The study created six different study models in a virtual environment: healthy mature maxillary central teeth, intact immature maxillary central teeth, mature maxillary central teeth with fiberglass post associated with resin composite crown restoration, immature maxillary central teeth with fiberglass post associated with resin composite crown restoration, mature maxillary central teeth with fiberglass posts and zirconia restoration, and immature maxillary central teeth with fiberglass posts and zirconia restoration. Loading conditions simulating mastication, trauma, and bruxism were applied to each of the models at different angles and amounts. The von Mises and the maximum and minimum principal stress values in tooth structures (dentin) and support structures (bone, PDL) and materials were observed using finite element stress analysis. RESULTS: The highest stress values in the tissue and the restoration structure were observed for masticating force and crowns rehabilitated with zirconia restorations. None of the compared loading conditions and restorations showed destructive stress values on periodontal ligament or bone. CONCLUSION: The mature and immature endodontically treated central maxillary incisors can be better rehabilitated using fiberglass post associated with resin composite crown restoration and may be preferred to zirconia restorations in order to reduce the stresses on the surrounding tissues and teeth. However, further clinical studies are needed to fully explore this topic.

Effect of wire diameter and extent of wire composite splint on the mobility of luxated and anchor primary teeth: A typodont study.

BACKGROUND/AIMS: The recommendations for splinting are well established for the injuries of permanent dentition; however, ambiguity still exists for the injuries in primary dentition. Hence, this study aimed to determine the most appropriate dimensions of stainless steel wire and its extent, for achieving the physiologic mobility in primary dentition. MATERIAL AND METHODS: This study was designed as an in vitro experiment by using a typodont model of primary dentition. The baseline mobility of primary maxillary incisors was calibrated to the physiologic mobility of natural primary incisors by using a Teflon tape wrapped around the roots of resin teeth. Splinting was done using a stainless steel wire of 0.2 mm (Group I), 0.3 mm (Group II), and 0.4 mm (Group III). These groups were subdivided (a, b, and c) on the basis of the extent of the splint, and pre splint mobility (Pre-PV) and post-splint mobility (Post-PV) were tested by Periotest M. The splint effect was calculated by subtracting Post-PVs and Pre-PVs. RESULTS: The normal values of mobility in healthy human volunteers ranged from 10.5 to 13. The overall splint effect was higher in Group III irrespective of the extent of the splint, whereas it was found to be the lowest in Group I (b and c). The splint effect increased with the extent of the splint in all the groups. Among all the groups, the splint effect on the anchor teeth was observed to increase with the extent of the splint and the diameter of the wire. CONCLUSION: The mobility of the injured and anchor teeth splinted with 0.2-mm stainless steel wire was similar to the pre-splint and physiologic mobility. The most favorable extension was one tooth adjacent to the injured tooth on each side for both 0.2- and 0.3-mm wires.

Novel AI-based tool for primary tooth segmentation on CBCT using convolutional neural networks: A validation study.

BACKGROUND: Primary teeth segmentation on cone beam computed tomography (CBCT) scans is essential for paediatric treatment planning. Conventional methods, however, are time-consuming and necessitate advanced expertise. AIM: The aim of this study was to validate an artificial intelligence (AI) cloud-based platform for automated segmentation (AS) of primary teeth on CBCT. Its accuracy, time efficiency, and consistency were compared with manual segmentation (MS). DESIGN: A dataset comprising 402 primary teeth (37 CBCT scans) was retrospectively retrieved from two CBCT devices. Primary teeth were manually segmented using a cloud-based platform representing the ground truth, whereas AS was performed on the same platform. To assess the AI tool's performance, voxel- and surface-based metrics were employed to compare MS and AS methods. Additionally, segmentation time was recorded for each method, and intra-class correlation coefficient (ICC) assessed consistency between them. RESULTS: AS revealed high performance in segmenting primary teeth with high accuracy (98 ± 1%) and dice similarity coefficient (DSC; 95 ± 2%). Moreover, it was 35 times faster than the manual approach with an average time of 24 s. Both MS and AS demonstrated excellent consistency (ICC = 0.99 and 1, respectively). CONCLUSION: The platform demonstrated expert-level accuracy, and time-efficient and consistent segmentation of primary teeth on CBCT scans, serving treatment planning in children.

PREVALENCE OF CARIES PATTERNS IN THE 21ST CENTURY PRESCHOOL CHILDREN: A SYSTEMATIC REVIEW AND META-ANALYSIS.

OBJECTIVE: This systematic review aimed to describe and evaluate the caries patterns among the 21st century preschool children globally. METHOD: Six electronic databases (Pubmed, Embase, Medline, Web of Science, EBSCOhost, and Scopus) were searched using predetermined terms. Dual independent screening of all retrieved abstracts was performed to identify studies conducted after year 2000 and the caries pattern among preschool children was investigated. Data regarding the prevalence of caries by tooth type and surface were extracted. Meta-analyses, subgroup analyses and meta-regression were carried out with the statistics software Stata using the random-effects model. RESULTS: A total of 2642 records were screened, and 43 observational studies were finally included. Cavitated caries lesions were commonly found in the maxillary incisors and molars in both arches among preschool children. The highest caries prevalence was found in the maxillary central incisors (29.1%, 95%CI: 25.5%-32.7%) and the mandibular second molars (28.5%, 95%CI: 24.7%-32.3%), while the mandibular lateral incisors had the lowest prevalence (1.7%, 95%CI: 1.5%-2.0%). Occlusal surfaces of the mandibular molars were the most frequently affected by caries, whereas caries hardly affected the lingual surfaces of lower anterior teeth. Caries pattern on the left and right sides was symmetrical. The overall caries prevalence was significantly higher in the maxillary teeth. Caries prevalence was higher in the older children, whereas the caries pattern was not significantly different among children from countries with different human and economic development levels. CONCLUSION: Cavitated carious lesions were more commonly observed in the maxillary incisors and molars in both arches. The prevalence of caries varies significantly with child's age and primary tooth type. However, preschool children exhibit a similar pattern of caries, regardless of the time, socioeconomic status or geographical location.

Pain, discomfort, and functional impairment after extraction of primary teeth in children with palatally displaced canines - a randomized control trial comparing extraction of the primary canine versus extraction of the primary canine and the primary first molar.

CONCLUSION: Primary canines and first molars can be extracted in a way that is associated with relatively low levels of pain and discomfort during and after the procedures. Double extractions induced more pain and discomfort than single extractions, which should be accounted for in the treatment planning. MATERIAL AND METHODS: Twenty-eight children, aged 9.5-14 years with displaced permanent maxillary canines were randomly assigned for extraction of the primary canine only or the primary canine and the primary first molar. Pain and discomfort were rated on visual analogue scales, and influence on daily activities was assessed by a questionnaire that has been previously tested for reliability and validity. Differences between groups were assessed by independent samples t-tests, Mann-Whitney U-tests or the Fisher's exact test. OBJECTIVE: To assess pain, discomfort, and functional impairment in children experiencing extraction of primary canine or primary canine and primary first molar as an interceptive treatment for palatally displaced permanent canines. RESULTS: Tooth extraction was associated with low levels of pain and discomfort on a group level. Extraction of both the canine and the first molar was associated with significantly more pain and discomfort than was the extraction of the canine only. Extractions were associated with chewing problems among one-third to half of the children, otherwise, few children reported any jaw impairment after extraction.

Traumatic dental injuries in the primary lower incisors.

BACKGROUND: Primary lower incisors are susceptible to traumatic dental injury (TDI), which may affect both primary and permanent dentitions. AIM: This study aimed to evaluate the prevalence of TDIs in the primary lower incisors and the factors associated with their occurrence and with the incidence of sequelae in the permanent successor teeth. DESIGN: Dental files (n = 2926) from patients who attended a reference center for dental trauma in the primary teeth, from 1998 to 2020, were screened. Multilevel Poisson regression analyses were conducted between exploratory variables related to the traumatized teeth and outcome variables: occurrences of severe TDI and sequelae in the permanent successor. Prevalence ratios (PRs), relative risks (RRs), and respective 95% confidence intervals (95% CIs) were calculated. RESULTS: One hundred and thirteen (3.9%) children and 208 teeth presented with TDIs in the primary lower incisors. The prevalence of severe TDI was lower in 4-year-olds (PR = 0.43; 95% CI = 0.19-0.94) than in 2-year-olds. Moreover, severe TDI was significantly associated with the occurrence of sequelae in the permanent successors (RR = 3.97; 95% CI = 1.72-9.18), when compared to not severe TDI. CONCLUSIONS: The prevalence of TDI in the primary lower incisors is low, with a higher prevalence in children younger than 3 years. Older children also present less frequently with severe TDI, and the risk of sequelae in permanent teeth is higher following severe TDI.

Evaluation of accuracy of an electronic apex locator in presence of sodium hypochlorite in primary teeth with and without resorption.

This study compared the accuracy of Root ZX mini apex locator in presence of sodium hypochlorite (NaOCl) in primary molars with and without apical resorption. Sixty-four extracted primary lower molar teeth with 32 root resorption and 32 without resorption were selected. To determine the actual working length (AWL), a K-file was inserted into the root canal until the tip of the file was visible at the major foramen or the resolution level. It was then withdrawn 1 mm. This value was recorded as AWL. The teeth were then divided subgroups (with/without NaOCl). To determine the electronic working length, a Root ZX mini apex locator in canals with/without NaOCl was used. A K-file was inserted into the canal to just beyond the foramen, as indicated by the flashing "APEX" bar, and the electronic working length was determined by subtracting 1 mm from this length. The deviation of the Root ZX mini measurement from the AWL was determined. Student's t-test was used for statistical analysis. In teeth with no resorption, the measurement accuracy rates (within+/-0.5 mm) of non-NaOCl and NaOCl groups were 84.37% and 81.25%, respectively (p > 0.05); within+/-1 mm, the non-NaOCl and NaOCl demonstrated 100% and 96.87% accuracy, respectively (p > 0.05). In teeth with resorption, the measurement accuracy rates (within+/-0.5 mm) was 81.25% for the non-NaOCl and 62.50% for the NaOCl, respectively (p < 0.05). The measurement accuracy rates (within+/-1 mm) of the non-NaOCl and NaOCl was 96.87% and 84.37%, respectively (p < 0.05). The presence of NaOCl in the root canal affected the accuracy of the Root ZX mini in primary teeth with apical resorption, but not in teeth without resorption.

The comparison of calcium hydroxide + biostimulation, calcium hydroxide, formocresol, and MTA pulpotomies without biostimulation in primary teeth: 12-months clinical and radiographic follow-up.

This study has aimed to evaluate the clinical and radiographic success rates of calcium hydroxide pulpotomy (CH) with biostimulation (PBMT) and compare them to that of CH, formocresol (FC), mineral trioxide aggregate (MTA) pulpotomies without PBMT in primary molars. A total of 172 pulpotomies were performed on primary first or second mandibular molars in 94 children who were 5-8 years old. The pulpotomy procedure was performed with four different techniques. In the PBMT group, before the CH placement, 820-nm diode laser radiation was applied to each pulp-stump for 12 s (10 mW, 2.5 J/cm2). The clinical (lack of spontaneous pain, abscess or fistula, and pathological mobility) and radiographic success (lack of periapical/furcal lesions and internal/external resorption) were recorded at 6 and 12 months. The data was statistically evaluated. p value < 0.05 was considered as significant. After 12 months, the clinical and radiographic success rate (a tooth with at least one of the findings was considered unsuccessful) was 97%/92% for FC and 97%/95%, 87%/73%, and 71%/45% for MTA, CH + PBMT, and CH, respectively. There was no significant difference between the CH + PBMT and the other groups in clinical success, while a significant difference was found between CH and FC, MTA groups. In radiographic success, there was a significant difference between the CH and the other groups. No significant difference was found between the 6th- and 12th-month results in clinical success for all the groups. A decrease in success over time was seen only in the CH group for radiographic results. CH without PBMT showed the worst clinical and radiographic results among the groups. CH + PBMT showed similar clinical success compared to the MTA and FC groups. In radiographic success, CH + PBMT showed higher success compared to CH, but this success was not high as compared to MTA and FC.

Odontoma malformation and disturbances of eruption subsequent to traumatic dental injuries: A literature review and a case report.

Due to the close proximity of the primary teeth with the developing permanent successors, several developmental alterations in the permanent successors have been reported as consequences of traumatic dental injuries to the primary dentition. When they occur at a very young age such trauma could disturb normal tooth development and cause rare anomalies, including sequestration of the permanent tooth germ and odontoma-like malformations. A literature review of case reports with a history of trauma and odontoma formation is discussed in this paper. This paper also includes a case report of a patient, who was 3-years and 5-months old, when she was seen at the University of California, Los Angeles Children's Dental Center for the first time. The grandmother reported that the child was dropped from the father's lap when she was 2 weeks old and suffered head trauma and multiple skull fractures.

Evaluation of composite restorations in primary molars subjected to selective caries removal associated with antimicrobial photodynamic therapy: A randomized controlled trial.

BACKGROUND: Antimicrobial photodynamic therapy (aPDT) has been used as an adjunct treatment of deep caries lesions; however, studies on the effects of aPDT on the longevity of restorations are still limited. AIM: To evaluate the clinical performance of composite restorations in primary molars subjected to selective caries removal (SCR) associated with aPDT. DESIGN: A randomized clinical trial was designed. Primary molars of patients (mean age 6.15 years) with deep caries lesions without signs and symptoms of pulpal involvement were selected. A total of 64 teeth were randomly divided into groups G1 (SCR, 32 teeth) and G2 (SCR + aPDT, 32 teeth) for treatment, restored with composite, and evaluated after a week (T0 ), 6 months (T1 ), and 12 months (T2 ) according to the criteria of FDI. Groups were compared using the Rao-Scott chi-squared test and the logistic regression analysis for complex designs to account for multiple observations per subject (alpha = 0.05). RESULTS: From all FDI criteria evaluated, the marginal adaptation for the SCR + aPDT group was significantly better in comparison with the SCR group at T0 and T2 in the logistic regression analysis (T0: OR = 0.151; 95% CI = 0.03-0.068, P = .015; and T2: OR = 0.201; 95% CI = 0.05-0.79, P = .022). CONCLUSION: The marginal adaptation of primary molar resin restorations was positively affected by aPDT after 12 months of follow-up.

Success of medicaments and techniques for pulpotomy of primary teeth: An overview of systematic reviews.

BACKGROUND: Pulpotomy is an effective, vital pulp therapy procedure for caries-affected or traumatized primary teeth. Though its efficacy is widely accepted, the superiority of medicaments and techniques remains debatable. AIM: The aims of this review were to compare the success rates of various pulpotomy medicaments or techniques, assess the methodological quality of reviews, and grade the level of evidence for each comparison. DESIGN: This review followed the principles of evidence-based medicine and recommendations for the overview of systematic reviews. An a priori protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42021244489). A comprehensive literature search was performed by two reviewers, and studies were selected from various databases according to predefined criteria. Two reviewers independently used a self-designed pilot-tested form to extract data from the selected studies. A quality analysis was performed using A MeaSurement Tool to Assess systematic Reviews-2 (AMSTAR-2) and the ROBIS tool. Reporting characteristics and overlap of the primary studies were also assessed. We used modified Köhler's criteria for evaluating the quality of evidence for outcomes of included systematic reviews and meta-analyses. RESULTS: The scrutiny of 62 full-text articles resulted in the inclusion of eight systematic reviews. The quality of four of the reviews was found to be critically low, and the overlap of primary studies in the meta-analyses was found to be high. Pulpotomy medicaments/techniques, except calcium hydroxide, had success rates of more than 80% for all domains and time periods. Most of the comparisons revealed no differences in the clinical, radiographic, or overall success rates. Mineral trioxide aggregate, however, was found to have better radiographic and overall success rates than calcium hydroxide at periods greater than 12 and 18 months. It also had a greater radiographic success rate than full-strength/1:5 diluted and full-strength formocresol at 24 months. Formocresol was found to have better overall success rates than calcium hydroxide at all time periods and better radiographic success rates at 12 months. Only 12 of the 63 comparisons had suggestive or weak evidence, whereas all others had either negligible evidence or insufficient data. CONCLUSIONS: The pulpotomy medicaments/techniques, except calcium hydroxide, showed success rates of more than 80%, whereas most comparisons revealed no differences. Mineral trioxide aggregate, however, was found to be better than calcium hydroxide and formocresol in several respects. This study highlights the lack of evidence regarding the choice of pulpotomy agents for the treatment of caries-affected primary teeth and elucidates the domains that require primary studies in the future.

Symmetry of carious lesions in primary and permanent teeth in children as a predictor of future caries patterns.

This study evaluated the bilateral symmetry of carious lesions in the primary and permanent teeth of children. The clinical records of patients aged 3 to 14 years who had carious lesions were evaluated. Dental caries was assessed using the modified decayed, missing, and filled teeth (dmft/DMFT) index, and the biofilm was assessed using the O'Leary plaque control record. The results were analyzed considering the presence or absence of caries and the stages of caries. The kappa coefficient between the left and right sides was calculated, and the chi-square test was applied (P < 0.05). The sample consisted of 206 children and 4802 teeth (2127 primary and 2675 permanent teeth). Fifty-one percent of the sample was female, and the mean age was 8.28 (SD 1.62) years. The mean number of dmft/DMFT was 4.45 (SD 3.61), and the mean O'Leary plaque index was 27.38%. The overall symmetry for the presence/absence of dental caries was 49.5% (n = 342), and the symmetry for the stage of caries was 43.5% (n = 301). The symmetry was similar in primary and permanent teeth for the presence/absence of caries (50.83% and 47.39%, respectively) and stages of caries (42.08% and 45.89%, respectively). Among the teeth that showed symmetry of carious lesions, there was an association between the hygiene condition and the presence of lesions in all maxillary and mandibular primary second molars and in the mandibular permanent right first molar (P < 0.05). A bilateral symmetric relationship of carious lesions was observed in the primary canines, primary first and second molars, permanent central and lateral incisors, first premolars, and permanent first molars in both the maxillary and mandibular arches. The results suggest that the presence of a carious lesion on a tooth surface can predict vulnerability to caries on the contralateral tooth, allowing the dentist to pursue targeted preventive action.

Cleaning efficacy of various root canal irrigants in primary teeth: a scanning electron microscopic study.

Root canal irrigation plays an important role in debridement and disinfection of the root canal system. The present study aimed to evaluate the efficacy of 17% ethylenediaminetetraacetic acid (EDTA), 2% iodine-potassium iodide (IKI), and 1% and 3% concentrations of sodium hypochlorite (NaOCl) for root canal irrigation in the anterior primary teeth. A total of 60 anterior primary teeth were selected and assigned to 1 of 4 irrigation groups (n = 15): 1, 17% EDTA; 2, 3% NaOCl; 3, 2% IKI; and 4, 1% NaOCl. The root canals in all groups were subsequently irrigated with normal saline following a 30-minute incubation period. The prepared specimens were cut longitudinally and imaged using scanning electron microscopy to evaluate the cleaning efficacy in the coronal, middle, and apical thirds. Data were analyzed using descriptive statistics as well as nonparametric Kruskal-Wallis and Mann-Whitney U tests. Group 2 (3% NaOCl) showed the greatest efficacy for cleaning the entire root canal (P < 0.01). Analysis of the different parts of the root canal revealed that group 2 also demonstrated the greatest efficacy in achieving a clean apical portion (P < 0.01). According to the results of the present study, 3% NaOCl offered a better performance in irrigating the root canals of primary teeth.

The effects of disinfection with Er, Cr:YSGG laser, application of CPP-ACP and sodium hypochlorite on shear bond strength.

Background: The effects of commonly used antimicrobial and anticariogenic agents on the adhesion of pit and fissure sealants were investigated in this study. Aims: The aim of this study is to evaluate the effects of erbium, chromium: yttrium-scandium-gallium-garnet (Er, Cr:YSGG) laser disinfection, casein phosphopeptides-amorphous calcium phosphate (CPP-ACP) containing paste and sodium hypochlorite application before the placement of a resin-based pit and fissure sealant on the shear bond strength of primary tooth enamel. Materials and Methods: The shear bond strength test evaluated the bond strength of sealants on the buccal enamel surfaces of primary molar teeth. The study groups were pit and fissure sealant without any preapplication, pre application of disinfection with Er, Cr:YSGG laser, disinfection with Er, Cr:YSGG laser and CPP-ACP containing paste, sodium hypochlorite, sodium hypochlorite and CPP-ACP containing paste and CPP-ACP containing paste. The pit and fissure sealants were placed using 4 mm diameter, 2 mm height cylindrical plastic tubes. Shear force was applied to each sample. The surfaces of the broken samples were detected under stereomicroscope and were grouped as adhesive, cohesive, and mixed. The results of the study were evaluated using the SPSS 16.0 package program for statistical analysis. Results: The groups where sodium hypochlorite and sodium hypochlorite with CPP-ACP were applied showed the lowest bond strength (p < 0.05). It was observed that most of the failures in these groups were adhesive-type failures. No significant difference was observed between the shear bond strengths of the other groups (p < 0.05). Conclusions: Er, Cr: YSGG laser and CPP-ACP containing paste are alternative methods for pre-application of fissure sealants.

Primary tooth autotransplantation: update and retrospective clinical study.

OBJECTIVE: A new technique of primary tooth autotransplantation has recently been published demonstrating reliable replacement of missing permanent incisors in young children due to trauma or agenesis. This retrospective clinical study reports on the longterm success of this new technique in a larger patient group regarding its potential to support bone and soft tissue growth. STUDY DESIGN: 40 children (age range: 2.7-17.6 years) received 53 primary tooth autotransplants (49 canines and 4 incisors) due to traumatic tooth loss (73%), agenesis (19%) or dysplasia/displacement (8%). Clinical and radiological follow-up examinations were performed to check up on root resorption, bone and soft tissue growth, survival and success. RESULTS: 22 transplants still present in the oral cavity of 18 patients yielded a success rate of 77%. The Kaplan-Meier estimator measured a median survival time of 86 months (7.2 years) for all 53 grafts. In all cases, increasing soft tissue and bone development enabled a successful prosthetic rehabilitation regarding aesthetics and function. CONCLUSIONS: Primary tooth autotransplantation reliably restores edentulous anterior space in children experiencing traumatic tooth loss or agenesis and acts as an immediate therapy before other therapies such as premolar transplantation or orthodontic space closure can be carried out at a later time. It guarantees the co-development of soft tissue and bone in the teenage jaw which is associated with high patient satisfaction and acceptance of this method.

Successful minimally invasive intervention in a primary central incisor after root fracture: A case report.

Root fractures vary in severity, extent, and location, according to the physical and mechanical aspects of the accident. Root fractures are rare in primary teeth and they affect dentin, cementum, periodontal ligament and the pulp. This paper reports a case of a two-and-a-half-year-old baby who had a root fracture of the upper right primary central incisor (tooth 51) as a consequence of trauma that was managed with minimally invasive intervention. After clinical and radiographic examinations, the presence of tooth mobility, pain, bleeding and a horizontal apical root fracture was diagnosed on tooth 51. The treatment of choice was splinting for 120 days, which can deliver excellent results regardless of the patient's age. The tooth was preserved without needing endodontic intervention until its physiologic exfoliation and normal eruption of its permanent successor. As sequelae to the fractured tooth 51, there was some coronal color alteration and dystrophic calcification of the root canal. This tooth did not develop ankylosis or mobility during the follow-up period. After 57 months of follow-up, repositioning and splinting were appropriate ways to manage this horizontal root fracture in the apical third of this primary tooth. It allowed the tooth to be preserved in the arch with normal function.

Dentigerous cyst formation following trauma to the primary incisors: A case report.

Although usually considered to be of developmental origin, dentigerous cysts (DCs) have been reported to form in response to chronic periapical inflammation associated with primary teeth that have necrotic, infected pulps. This article describes the management of a DC associated with tooth 21 in a seven-year-old Caucasian child with a history of multiple TDIs to the primary maxillary incisors. Chronic periapical inflammation associated with a necrotic pulp in tooth 61 was identified as the likely cause of the lesion. Initial conservative management involved marsupialization of the lesion by extracting the necrotic tooth 61. Following significant decompression of the cyst, surgical enucleation was carried out under general anaesthesia and an orthodontic attachment was bonded to the crown of the unerupted tooth 21 to facilitate traction. Histopathological assessment of the enucleated tissue confirmed it to be a DC. Two years after the initial presentation, teeth 21 and 22 had erupted into the oral cavity, improving patient aesthetics. However, the root of tooth 22 was transposed with the crown of the unerupted tooth 23. This case highlights the undesirable sequelae that may occur following delayed and inappropriate management of TDIs.

Immunocytochemical characterization of primary teeth pulp stem cells from three stages of resorption in serum-free medium.

BACKGROUND/AIMS: Dental pulp stem cells from primary teeth cultured in serum-free conditions may have clinical use for the repair and regeneration of teeth as well as other complex tissues and organs. The aim of this study was to test the change in the stem cell markers expression/ stem cell population in human primary pulp cells at the different stages of root resorption. METHODS: Caries-free human primary canines at defined stages of physiological root resorption were included (n = 9). In vitro cultures were established in xeno-free, serum-free Essential 8™ medium with human truncated vitronectin for cell attachment. An embryonic stem cell line (GENEA002) was used as a positive control. The expression of embryonic stem cell markers (Oct4, Nanog and Sox2), neural crest stem cell markers (nestin and Dlx2) and mesenchymal stem cell surface markers (CD90, CD73 and CD105) were investigated by immunocytochemistry. Mesenchymal stem cell markers CD105, CD73 and CD90 and haematopoietic markers: CD45, CD34, CD11b, CD19 and HLA-DR were quantified with flow cytometry. RESULTS: The early neural progenitor markers nestin and Dlx2 were detected in most serum-free cultured dental pulp stem cells, regardless of the tooth resorption stage from which they were harvested. Only isolated cells were found that expressed the embryonic stem cell transcription factors Oct4A, Nanog and Sox2, and in the late stages of resorption, no Oct4A was detected. The majority expressed the mesenchymal stem cell markers CD90, CD73 and CD105. Flow cytometry found positive signals for CD90 > 97.3%, CD73 > 99.6% and CD105 > 82.5%, with no detectable differences between resorption stages. CONCLUSIONS: This study identified populations of dental pulp cells in vitro with markers characteristically associated with embryonic stem cells, neural crest-derived cells and mesenchymal stem cells. Flow cytometry found CD105 expressed at lower levels than CD90 and CD73. The consistency of stem cell marker expression in cells cultured from teeth at different resorption stages suggests that pre-exfoliated primary teeth that are free of caries may provide a convenient source of multipotent stem cells for use in regenerative medicine.

Antimicrobial activity of root canal filling pastes used in pediatric dentistry.

This study evaluated the antimicrobial activity of root canal filling pastes commonly used in primary teeth: iodoform paste, zinc oxide-eugenol (ZOE), and analytical grade calcium hydroxide (Ca[OH]2). The materials were evaluated in the following 6 combinations: iodoform paste (Rifocort [prednisolone + rifampicin] + iodoform + camphorated paramonochlorophenol); zinc oxide + eugenol in a proportion of 1:3; zinc oxide + eugenol in a proportion of 1:5; Ca(OH)2 + water; iodoform paste + ZOE (1:3) + Ca(OH)2; and ZOE (1:3) + Ca(OH)2. Chlorhexidine gel (0.2%) served as the positive control. A commercial strain of Enterococcus faecalis (ATCC 25175) was plated in petri dishes containing 10 mL of brain-heart infusion agar culture medium with a hole in the center. The filling pastes (3 g) were manipulated and inserted in the hole. The plates were incubated at 37°C for 48 hours, and then the inhibition zone associated with each paste was measured. The experiments were carried out in triplicate (n = 3 per group). The data were submitted to analysis of variance and Tukey tests (P < 0.05). Iodoform paste resulted in the largest mean (SD) inhibition zone, 7.06 (0.74) mm. The smallest was obtained with Ca(OH)2 + water, the mean (SD) of 0.00 (0.00) mm indicating that these specimens did not form an inhibition zone. The ZOE pastes in proportions of 1:3 and 1:5 resulted in statistically similar mean (SD) inhibition zones of 1.86 (0.50) and 1.30 (0.18) mm, respectively (P > 0.05). Of the test materials, the combination of iodoform paste + ZOE + Ca(OH)2 presented the second largest inhibition zone, 6.27 (3.08) mm, significantly different from that of the non-iodoform pastes (P < 0.05). It can be concluded that iodoform paste, alone or in combination with ZOE + Ca(OH)2, demonstrates high antimicrobial activity, while the combination of ZOE + Ca(OH)2 demonstrates moderate activity.

A systematic review and meta-analysis of randomized clinical trials comparing rotary canal instrumentation techniques with manual instrumentation techniques in primary teeth.

BACKGROUND: Use of rotary instruments in the root canals of permanent teeth is well known; however, there are no evidence-based recommendations on the effectiveness of rotary canal instrumentation techniques over manual instrumentation techniques during root canal treatment in primary teeth. AIM: To appraise the current literature on the effectiveness of rotary canal preparation techniques compared to manual techniques during root canal treatment in primary teeth. DATA SOURCES: MEDLINE, Embase, Cochrane Library, Scopus, PubMed and Web of Science (1 January 1991 to 3 January 2019). STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS: Population: Children with primary teeth; Intervention: Rotary canal instrumentation; Control: Manual canal instrumentation; Outcomes: Success rates (clinical and/or radiographic), quality of root filling, instrumentation and root filling time, postoperative pain, cleaning effectiveness. STUDY APPRAISAL AND SYNTHESIS METHODS: Cochrane risk of bias tool 2.0 was used to ascertain the validity across five domains. Risk ratio (RR) for dichotomous variables and weighted mean difference for continuous variables were used as summary measures. The GRADE approach was used to assess the certainty of evidence using GRADE-pro software. RESULTS: A total of 13 trials were selected of 2471 records after screening of the databases. The RR of clinical success in rotary versus manual canal preparation technique was 1.01 (95% CI: 0.91-1.12; P = 0.913) at 6 months. The RR of radiographic success in rotary versus manual techniques was 0.97 (95% CI: 0.74-1.27; P = 0.805) at 6 months. The quality of root filling was not significantly different between the two groups (P = 0.062). The weighted mean difference of instrumentation time and canal filling time was significantly less with rotary techniques (P < 0.001); however, postoperative pain was non-significant across both techniques at 12, 24 and 72 h but significantly less with rotary techniques at 6 h (P < 0.001) and 48 h (P = 0.023). LIMITATIONS: Inclusion of only English literature. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: Rotary canal instrumentation had a similar clinical and radiographic success rate, less postoperative pain (at 6 and 48 h), and took less instrumentation time compared to manual instrumentation techniques (moderate level of evidence).