Advancing the assessment of pacifier effects with a novel computational method.

BACKGROUND: Numerous studies have demonstrated a high likelihood of malocclusions resulting from non-nutritive sucking. Consequently, quantifying the impact of pacifiers can potentially aid in preventing the development or exacerbation of malocclusions and guide the design of improved performance pacifiers. METHODS: This work proposes and assesses a computational methodology that can effectively gather crucial information and provide more precise data regarding the consequences of non-nutritive pacifier sucking. The computational framework utilized is based on solids4Foam [1, 2], a collection of numerical solvers developed within the OpenFOAM® computational library [3]. The computational model focuses on the palate of a six-month-old baby and incorporates various components such as palate tissues, pacifier and tongue, and considers the negative intraoral pressure generated and the tongue displacement. Different models were tested, each offering varying levels of detail in representing the palate structure. These models range from a simplified approach, with one tissue, to a more intricate representation, involving up to five different tissues, offering a more comprehensive palate model compared to existing literature. RESULTS: The analysis of results involved examining the distribution of stress on the palate surface, as well as the displacement and forces exerted on the dental crowns. By comparing the obtained results, it was possible to evaluate the precision of the approaches previously described in the literature. The findings revealed that the predictions were less accurate when using the simplified model with a single tissue for the palate, which is the most common approach proposed in the literature. In contrast, the results demonstrated that the palate model with the most intricate structure, incorporating five different tissues, yielded distinct outcomes compared to all other combinations. CONCLUSIONS: The computational methodology proposed, employing the most detailed palate model, has demonstrated its effectiveness and necessity in obtaining accurate data on the impact of non-nutritive sucking habits, which are recognized as a primary contributor to the development of dental malocclusions. In the future, this approach could be extended to conduct similar studies encompassing diverse pacifier designs, sizes, and age groups. This would foster the design of innovative pacifiers that mitigate the adverse effects of non-nutritive sucking on orofacial structures.

Infraocclusion in the Primary and Permanent Dentition-A Narrative Review.

The gradual movement of a tooth away from the occlusal plane is called infraocclusion or reinclusion. Reincluded teeth are most often deciduous molars, and permanent teeth are less frequently affected. Depending on the level of the infraocclusion, the severity of the disorder is classified as mild, moderate, or severe. The etiology of the phenomenon is not fully known. Tooth submerging can lead to serious complications, such as abnormal position of adjacent teeth, displacement of the bud of the permanent successor, shortening of the dental arch, or developmental disturbances of alveolar process. Early diagnosis of the tooth infraocclusion and regular monitoring of its progression help to avoid serious permanent sequelae. The treatment of reinclusion often involves only observation. However, in some cases, the therapeutic procedure requires interdisciplinary treatment by specialists from various fields of dentistry. This study presents current methods of diagnosis and treatment of patients with submerged teeth.

Mesenchymal Stem Cells from the Deciduous Tooth Pulp Lose their Ability to Suppress the Differentiation of Dendritic Cells during Long-Term Culturing.

A culture of cells expressing markers of mesenchymal stem cells (MSC) (CD73, CD90, CD44, CD29, and CD49b), but not hematopoietic cell markers, and capable of multilineage differentiation was isolated from the deciduous tooth pulp. Co-culturing with immature dendritic cells in the presence of LPS did not reveal an ability of the MSC to suppress the maturation of dendritic cells. On the contrary, co-culturing of MSC with monocytes in the presence of granulocyte-macrophage CSF and IL-4 led to complete suppression of monocyte differentiation into dendritic cells. However, long-term culturing of MSC from dental pulp showed that by the passage 11, they almost completely lose their suppressor ability. These results indicate that the immunological properties of MSC can change during culturing without changing their phenotypic markers. This should be taken into account when creating biomedical cell products.

Count Me in, Count Me out: Regulation of the Tooth Number via Three Directional Developmental Patterns.

Tooth number anomalies, including hyperdontia and hypodontia, are common congenital dental problems in the dental clinic. The precise number of teeth in a dentition is essential for proper speech, mastication, and aesthetics. Teeth are ectodermal organs that develop from the interaction of a thickened epithelium (dental placode) with the neural-crest-derived ectomesenchyme. There is extensive histological, molecular, and genetic evidence regarding how the tooth number is regulated in this serial process, but there is currently no universal classification for tooth number abnormalities. In this review, we propose a novel regulatory network for the tooth number based on the inherent dentition formation process. This network includes three intuitive directions: the development of a single tooth, the formation of a single dentition with elongation of the continual lamina, and tooth replacement with the development of the successional lamina. This article summarizes recent reports on early tooth development and provides an analytical framework to classify future relevant experiments.

Evaluation of the reasons for failure in teeth with vital amputation treatment.

AIM: This study aims to evaluate the primary teeth undergoing amputation due to dental caries or trauma clinically and radiologically. MATERIAL AND METHODS: The amputation treatment of 90 primary teeth of 58 patients (Female: 20, Male: 38) aged 4-11 years was evaluated clinically and radiologically. Calcium Hydroxide was used for amputation in this study. Composite or amalgam was preferred as filling material in the same session of the patients. Clinical/radiological (Periapical/Panoramic X-ray) examination was performed on the teeth that were unsuccessful in treatment, on the day of the patient's complaint, and at the end of 1 year in the others. RESULTS: According to the clinical and radiological findings of the patients, 14.4% of the boys and 12.3% of the girls were unsuccessful. Amputation in male was a need in the 6-7 age group with a rate of 44.6% at most. Amputation in females was a need in the 8-9 age group with a rate of 52% at most. CONCLUSION: Success in amputation treatment depends on the tooth, the dentist, and the dental material applied.

Comparison of the morphology of the primary first molars and the forms of stainless steel crowns used in clinical practice.

This study aimed to assess the difference in the mesiodistal (MD) and buccolingual (BL) dimensions of primary first molars between Taiwanese boys and girls using a three-dimensional (3D) scanner (Microscribe G2 digitizer), record the coordinates in the 3D systems of Graph-R Project and reconstruct 3D images for subsequent analysis. We also determined whether the differences in these parameters between primary first molars and stainless steel crowns (SSC, 3M ESPE, No. 2-7) could be used as a reference for selecting a suitably-sized SSC and performing adjustments during restoration. The results indicated a statistically significant difference in the mesiodistal distance of lower primary first molar crowns between boys (7.75 ± 0.38 mm) and girls (7.41 ± 0.41 mm) (p < 0.05) but no differences in the mesiodistal distance of upper primary first molars between the two sexes. The mean mesiodistal distances of the upper and lower primary first molars of boys were close to SSC size 4 and 3, respectively, while those of girls were close to size 3 in both arches. Overall, the buccolingual distance between the first maxillary and mandibular molars of Taiwanese children was greater than the buccolingual distance between the 3M ESPE SSC. Reducing the buccolingual length of the abutment teeth might quickly help achieve a better fit, reduce chair time, and minimize patient discomfort. In addition, trimming the mesial and distal metal margins of SSCs might help reduce microleakage from the crown margins and improve its retention and survival rate. In conclusion, the 3D scanning and analysis method used in this study can serve as a reference for fabricating SSC to achieve better crown adaptation and improve dental procedures.

Prevalence of dental floss use in deciduous dentition: A systematic review and meta-analysis.

OBJECTIVES: Adherence to the daily use of dental floss in childhood is recommended by various international health institutions/organizations. This systematic review (PROSPERO number CRD42020205232) aims to evaluate the prevalence of dental floss use in deciduous dentition. MATERIALS AND METHODS: A systematic review was conducted in six databases (B-on, Cochrane Library, PubMed, Scielo, Science Direct and Web of Science) up to December 2020. The CoCoPop mnemonic allowed for obtaining 2333 articles and resulted in the inclusion of 7 observational studies that evaluated the prevalence of dental floss use (primary outcome) in children up to 6 years old. The Joanna Briggs Institute critical appraisal checklist was used to evaluate the risk of bias, showing that most articles presented good quality. Meta-analyses were performed using the proportion of dental floss use (yes or once/day) and the random effects model. RESULTS: The meta-analysis showed a prevalence of dental floss use of only 12.60% (95% CI: 7.69%-18.52%) based on studies with high heterogeneity of results (I2  = 94.75%; 95% CI: 91.44%-96.78%). Six of the seven studies showed that more than 70% of children never used dental floss. CONCLUSIONS: A low prevalence of dental floss use was observed in children up to 6 years old. Given the diversity of evaluating the use of dental floss, different options should be the target of standardization in future studies.

Material of choice for non-invasive treatment of dentin caries: An in vitro study using natural carious lesions.

INTRODUCTION: In community settings with limited dental personnel and equipment, and in an era when the aerosol transmission of infectious agents is on the rise, a non-invasive approach to caries management is critical. To provide information on non-invasive material selection, the aim of this study was to compare the remineralization effect of commonly used fluoride-containing materials, adjunctive to the everyday use of fluoride toothpaste (F-toothpaste), on primary tooth natural dentin caries. METHODS: Fifty-five specimens were randomly divided into five groups: 38% silver diamine fluoride (SDF), 5% fluoride varnish (F-varnish), glass-ionomer cement (GIC), deionized water (DW) with F-toothpaste slurry, and DW as a control group (n = 11). The lesion depth and mineral density were measured before and after bacterial pH-cycling using micro-computed tomography. The percentage of mineral density change (%MDchange) was quantified. The dependent t-test, Wilcoxon-Signed-Rank Test, and one way ANOVA with Bonferroni correction were used to analyse the data. RESULTS: SDF application reduced lesion depth from 844.6 to 759.1 µm (p < 0.045) while increasing mineral density from 551.4 to 763.0 mgHA/cm3 (p < 0.003). Only mineral density rose from 600.2 to 678.4 mgHA/cm3 (p < 0.013) when GIC was used. The other groups showed no difference. The highest %MDchange was also found after SDF treatment (49.7%, p < 0.05), whereas GIC (17.2%, p < 0.05) presented a higher percentage than the F-varnish (2.0%), F-toothpaste (-1.1%) and no-treatment groups (-1.4%). CONCLUSION: In this in vitro study, where the pH of cycling was almost neutral, using SDF as an adjunct to F-toothpaste resulted in the highest remineralization compared with other remineralizing materials.

Effects of mechanical force on proliferation and apoptosis of stem cells from human exfoliated deciduous teeth.

OBJECTIVES: This study was designed to explore the effects of mechanical force on the proliferation, apoptosis, and morphology of stem cells from human exfoliated deciduous tooth pulp (SHEDs). MATERIALS AND METHODS: Caries-free stranded deciduous teeth were extracted, and SHEDs were isolated through enzymatic digestion. The cultured SHEDs were subjected to different levels of mechanical stimuli (0, 100, 200, and 300 g) for 7 days (30 min/day) using external centrifugal force. Cell proliferation was evaluated with the CCK-8 assay, and the cell cycle and apoptosis were assessed by flow cytometry. The cell morphology was examined using transmission electron microscopy. RESULTS: Cell proliferation assay showed no differences between the three stimulation groups and the control group in day 1 to day 3. From the 4th day, cell proliferation was significantly lower in the mechanical force groups than in the control group, but no significant difference was observed among the three mechanical force groups. Besides, there was no significant difference in cell apoptosis among the four groups for 7 days. On day 7 after stimulation, the SHEDs were shrunken, with significantly increased isochromosome in the nucleus and an increase in lysosomes. CONCLUSIONS: Mechanical force can inhibit the proliferation and affect morphology of SHEDs, but it has no effect on cell apoptosis. CLINICAL RELEVANCE: Mechanical force stimulation significantly inhibited cell proliferation of SHEDs. Mechanical force stimulation had no significant effect on cell apoptosis of SHEDs. The morphology and ultrastructure of SHEDs changed after mechanical force stimulation.

Sealing of cavitated occlusal carious lesions in the dentine of deciduous molars: a two-year randomised controlled clinical trial.

OBJECTIVES: This two-arm, parallel-group, tooth-randomised, controlled noninferiority clinical trial aimed to compare survival rates between the sealing and restoring of cavitated occlusal carious lesions in dentine [International Caries Detection and Assessment System (ICDAS) 5] of deciduous molars using resin-modified glass-ionomer cement (RMGIC) and to assess caries progression radiographically. MATERIALS AND METHODS: A total of 68 molars with ICDAS 5 occlusal lesions were randomly allocated into two groups, a sealing group (n = 31), in which RMGIC was placed directly over the carious lesion, and a restoration group (n = 37), in which a restoration with the same material was placed after selective caries removal. During the baseline and follow-up visits, dental caries was registered and caries activity was assessed according to a visuotactile criterion. At baseline, patient caries status (dmf-t) and cavity depth and extent (mesiodistal and buccolingual) were measured before RMGIC placement. An independent and blinded examiner evaluated the treated teeth using the USPHS criteria after one and two years. Standardised interproximal radiographs were taken for caries progression assessments. RESULTS: During the follow-up period, no lesion progression was observed radiographically. After one year (n = 60; 27 sealed and 33 restored) and two years (n = 48; 23 sealed and 25 restored) of follow-up, the treatment success rates were 78.8% and 76.0% in the restoration group and 59.3% and 47.8% in the sealing group, respectively. Multivariate Cox regression showed that lesions smaller than 2 mm in the mesiodistal extent were less prone to fail after one year (p = 0.03). However, survival curves (log-rank test) were statistically significantly different only after two years (p < 0.001). CONCLUSIONS: Sealing ICDAS 5 occlusal lesions of deciduous molars using RMGIC achieved lower survival rates than restorations. Both sealing and restoration effectively arrested caries progression for two years. Clinical relevance Sealing dentine carious lesions can be effective for treating lesions involving the inner and outer half of the dentine. Ultraconservative treatments can arrest carious lesions presenting obvious cavitation in primary molars. TRIAL REGISTRATION: ReBEC Register no. RBR-225n35.

Prognosis of primary teeth following intrusive luxation according to the degree of intrusion: A retrospective cohort study.

BACKGROUND/AIM: The degree of intrusion is an important aspect to be evaluated when treating children following intrusive luxation. The aim of this retrospective cohort study was to evaluate re-eruption rates and the occurrence of sequelae in intruded primary teeth according to the degree of intrusion. MATERIAL AND METHODS: A total of 238 teeth from 168 patients diagnosed with and treated for intrusion over a 16-year period at a specialized trauma center in South Brazil were included in this study. Patient details, including demographic characteristics, tooth affected, presence of sequelae of trauma during the follow up (pulp necrosis and infection, crown discoloration and abnormal mobility), and any effects on the permanent successors, were collected from their records. Photographs were analyzed to determine the degree of intrusion (Grade I, II, or III) and spontaneous re-eruption during follow up. Re-eruption and occurrence of sequelae according to the degree of intrusion were evaluated using the chi-squared test. The level of significance was set at 5%. RESULTS: Most teeth were maxillary central incisors (87.8%) with Grade I intrusion (32.8%). In the first 30 days, 13.1% had signs of re-eruption. After 3-6 months, the frequency of re-eruption increased to 58.7%. Of the teeth evaluated 6 months or more after intrusion, 68% had re-erupted. Total intrusion (Grade III) was associated with pulp necrosis and infection (p = .002), but the degree of intrusion was not associated with the presence of crown discoloration or abnormal mobility. Of the 78 permanent successors evaluated, 52.6% had developmental disturbances. CONCLUSION: Most intruded primary teeth re-erupted spontaneously, and the degree of intrusion was associated with a worse prognosis.

Gene expression patterns associated with dental replacement in the rabbit, a new model for the mammalian dental replacement mechanisms.

BACKGROUND: Unlike many vertebrates with continuous dental replacement, mammals have a maximum of two dental generations. Due to the absence of dental replacement in the laboratory mouse, the mechanisms of the mammalian tooth replacement system are poorly known. In this study, we use the European rabbit as a model for mammalian tooth development and replacement. RESULTS: We provide data on some key regulators of tooth development. We detected the presence of SOX2 in both the replacement dental lamina and the rudimentary successional dental lamina of unreplaced molars, indicating that SOX2 may not be sufficient to initiate and maintain tooth replacement. We showed that Shh does not seem to be directly involved in tooth replacement. The transient presence of the rudimentary successional dental lamina in the molar allowed us to identify genes that could be essential for the initiation or the maintenance of tooth replacement. Hence, the locations of Sostdc1, RUNX2, and LEF1 vary between the deciduous premolar, the replacement premolar, and the molar, indicating possible roles in tooth replacement. CONCLUSION: According to our observations, initiation and the maintenance of tooth replacement correlate with the presence of LEF1+ cells and the absence of both mesenchymal RUNX2 and epithelial Sostdc1+ cells.

The effect of combined maxillary pad movable appliance and FR-III functional appliance in the treatment of skeletal Class III malocclusion of deciduous teeth.

BACKGROUND: To evaluate the therapeutic effect of maxillary pad movable appliance combined with FR-III functional appliance in treating skeletal Class III malocclusion of deciduous teeth and provide a reference for optimizing clinical treatment methods. METHODS: A total of 30 pediatric patients were randomly selected between April 2012 and April 2019. They were in stage IIA osseous skeletal Class III malocclusion, treated with maxillary pad movable appliance to relieve the reverse, combined with FR-III functional appliance to maintain a median relationship to stage IIIA. A self-control study of children before and after treatment was used, and paired t-test was used to evaluate the changes in the measurement indexes of the IIA and IIIA stage X-rays and changes in the bone and soft tissue profiles. RESULTS: After 3 years of treatment, SNA, ANB, and NA-PA in the sagittal osteofacial index of the jawbones increased, SNB decreased, and the Y-axis angle in the vertical index of the jawbones increased. U1-SN, U1-NA, U1-NA distance, L1-MP, L1-NB, and L1-NB distance in the index of labial inclination of upper and lower central incisors increased, while U1-L1 decreased. The sagittal anomalies of the jawbones were improved, and there were significant differences before and after treatment (P < 0.05). FCA, ULP, and UL-EP increased, soft-tissue facial prominence and facial height increased, and the relationship between the upper lip and the aesthetic plane was harmonious. None of the 30 children with skeletal Class III malocclusion in the deciduous stage experienced recurrence in stage IIIA. CONCLUSIONS: Combined treatment with the maxillary pad movable appliance and the FR-III functional appliance is suitable for children with skeletal Class III malocclusion in the deciduous stage.

[Initial establishment of digital reference standardized crown models of the primary teeth].

OBJECTIVE: To explore the construction process of the digital reference crown models, and to initially establish the digital reference crown models of the primary teeth to lay the foundation for the establishment of the standardized crown models and the future related applications of computer-aided design/computer-aided manufacture (CAD/CAM) technology to pediatric dentistry. METHODS: This study randomly selected children who were caries free, aged from 4 to 5 years in several kindergartens of Haidian District of Beijing.Plaster dental models were made for the children after taking complete impressions.The digital dental models were reconstructed by using the three-dimensional (3D) dental model scanner.And then, Geomagic Studio, a 3D reverse engineering software, was employed to extract the single dental crown data, the mesiodistal and buccolingual diameters and the height of the crowns were measured.The object was reduced or enlarged by a numerical factor, and then the size of each dental crown was standardized.A total of 3-5 points features on the crown were created, and all the objects were aligned through the functions of feature-based alignment.Finally, through average-based object creation and smoothing, the digital models of reference crowns of the primary teeth were established. RESULTS: A total of 40 plaster dental models from 16 boys and 26 girls were selected out for our further study.The digital dental models were reconstructed, and the mesiodistal and buccolingual diameters and the height of the crowns were measured by using reverse engineering technology.Comparing the results of using mesiodistal diameter, buccolingual diameter and height as the standards, we chose the mesiodistal diameters of crowns to do the standardization, and successfully established the digital reference models of 20 primary teeth crowns with detailed surface characteristics. CONCLUSION: In this study, the digital reference crown models of the primary teeth were established by reverse engineering technology, providing reference value for the standardized crown models and application for clinical practice, scientific research and teaching.Furthermore, this study also contributes to the extensive application of CAD/CAM technology in pediatric dentistry and the development of CAD/CAM dental systems with independent intellectual property rights.

[Early loss of primary molar and permanent tooth germ caused by the use of devitalizer during primary molar root canal therapy: Two cases report].

Devitalization has been widely used in the root canal therapy of primary and permanent teeth in China more than ten years ago. With the development of local anesthetic drugs and injection technologies, this treatment method with high potential risks has been gradually abandoned. However, a questionnaire survey targeted all the participants at the 2018 China Pediatric Dentistry Conference showed that the devitalizer utilization proportion was still as high as 38.1% (383/1 005), even though the ratio was much lower than 75.5% (105/139) in 2003. These doctors had pay more attention to tissue burn caused by devitalizer marginal leakage or direct leakage, and know how to identify and handle with devitalizer burn. Devitalizers were usually made of arsenic trioxide, metal arsenic or paraformaldehyde, which have cytotoxicity, allergenicity, mutagenicity, carcinogenicity, and teratogenic effects on animals. Marginal leakage of devitalizers have high risks of causing soft and hard tissue necrosis. Most of the dentists have an understanding of the potential damages of arsenic containing devitalizers, so they will choose parafor maldehyde with relatively less toxicity. Paraformaldehyde has a certain self limitation, and there are few cases reported, so some dentists lack of vigilance. Paraformaldehyde can also causes tissue necrosis if leakage happens, and the treatment methods are similar to that of arsenic containing devitalizers. When handling with devitalizers burn, the necrosed soft and hard tissue, for example gingiva, alveolar bone or teeth that cannot keep, must be completely removed until fresh blood appears, then rinse with large amount of saline and seal with iodoform gauze. This paper described two cases of devitalizer burn during the root canal treatment of primary molars, both of the doctors failed to identify the devitalizer burn symptoms in the early stage, thus didn't do proper treatments immediately after burning. Resulting in the necrosis of large area of gingiva and alveolar bone, loss of primary molars and permanent tooth germs 1-2 months after devitalizer burn. This paper reported these two cases in detail in order to warn dentists the high risks of using any kind of devitalizers, help them learn how to identify and treat devitalizer burn, and remind them to stop using devitalizers as soon as possible.

RNA analysis based on a small number of manually isolated fixed cells (RNA-snMIFxC) to profile stem cells from human deciduous tooth-derived dental pulp cells.

BACKGROUND: Expression of stemness factors, such as octamer-binding transcription factor 3/4 (OCT3/4), sex determining region Y-box 2 (SOX2), and alkaline phosphatase (ALP) in human deciduous tooth-derived dental pulp cells (HDDPCs) can be assessed through fixation and subsequent immuno- or cytochemical staining. Fluorescence-activated cell sorting (FACS), a powerful system to collect cells of interest, is limited by the instrument cost and difficulty in handling. Magnetic-activated cell sorting is inexpensive compared to FACS, but is confined to cells with surface expression of the target molecule. In this study, a simple and inexpensive method was developed for the molecular analysis of immuno- or cytochemically stained cells with intracellular expression of a target molecule, through isolation of a few cells under a dissecting microscope using a mouthpiece-controlled micropipette. RESULTS: Two or more colored cells (~ 10), after staining with a chromogen such a 3,3'-diaminobenzidine, were successfully segregated from unstained cells. Expression of glyceraldehyde 3-phosphate dehydrogenase, a housekeeping gene, was discernible in all samples, while the expression of stemness genes (such as OCT3/4, SOX2, and ALP) was confined to positively stained cells. CONCLUSION: These findings indicate the fidelity of these approaches in profiling cells exhibiting cytoplasmic or nuclear localization of stemness-specific gene products at a small-scale.

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.

Association between malocclusion and the severity of dental trauma in primary teeth.

BACKGROUND/AIMS: The literature does not clearly state whether the type of malocclusion is associated with a specific type of trauma and the severity of the injury. Hence, the aim of this retrospective study was to assess the occlusal condition in children with traumatic dental injuries of the primary teeth, and the association between the occlusal characteristics and the type and severity of these injuries. MATERIAL AND METHODS: Data were collected from records of children treated at a dental trauma center in Brazil over a period of 16 years. The data included age, gender, etiology of the trauma, place of occurrence, number of affected teeth, type of trauma, and injury severity. The occlusal condition was assessed by a trained dentist using photographs of the patients from their first visit. Chi-square tests and Poisson regression were used for data analyses. RESULTS: This study included 209 patients, and most were aged between 2-4 years (50.55%). Multivariate regression analysis showed that children with an anterior open bite had a 47% higher prevalence of severe trauma than those who did not have an anterior open bite, and those with class II canines had a 56% higher prevalence of severe trauma than those with class I and III canines. Children with an anterior open bite had a 46% higher prevalence of injuries affecting multiple teeth than those without an anterior open bite. CONCLUSIONS: Anterior open bite and class II canine relationship were associated with a higher prevalence of severe traumatic dental injury in primary teeth, and anterior open bite was associated with trauma affecting multiple teeth.

The impact of caries status on supragingival plaque and salivary microbiome in children with mixed dentition: a cross-sectional survey.

BACKGROUND: Supragingival plaque and saliva are commonly used for microbiome analysis. Many epidemiological studies have identified deciduous teeth caries as a risk factor for caries development in first permanent molar (FPM); nevertheless, to the best of our knowledge, there are no reports on the effects of deciduous teeth caries on the microbiome of healthy FPM. Additionally, it remains unclear whether saliva can be used instead of supragingival plaque for caries microbial studies. Therefore, we aimed to elucidate this issue, and to characterize and compare the oral microbiome of healthy FPMs in children with different caries statuses and that from children with and without caries in a similar microhabitat, by PacBio sequencing. Currently, few studies have investigated the oral microbiome of children using this technique. METHODS: Thirty children (aged 7-9 years) with mixed dentition were enrolled; 15 had dental caries, and 15 did not. Supragingival plaques of deciduous molars and maxillary FPMs, and non-stimulating saliva samples were collected. DNA was extracted and the v1-v9 regions of 16S rRNA were amplified. Subsequently, PacBio sequencing and bioinformatic analyses were performed for microbiome identification. RESULTS: The microbial alpha diversity of the saliva samples was lower than that of the supragingival plaque (p < 0.05); however, no differences were detected between deciduous teeth and FPMs (p > 0.05). In addition, the alpha and beta diversity of children with and without caries was also similar (p > 0.05). Nonmetric multidimensional scaling and Adonis analyses indicated that the microbial structure of salivary and supragingival plaque samples differ (p < 0.05). Further analysis of deciduous teeth plaque showed that Streptococcus mutans, Propionibacterium acidifaciens, and Veillonella dispar were more abundant in children with caries than in those without (p < 0.05); while in FPMs plaque, Selenomonas noxia was more abundant in healthy children (p < 0.05). No differences in microorganisms abundance were found in the saliva subgroups (p > 0.05). CONCLUSION: We have determined that supragingival plaque was the best candidate for studying carious microbiome. Furthermore, S. mutans, V. dispar, and P. acidifaciens were highly associated with deciduous teeth caries. S. noxia may be associated with the abiding health of FPM; however, this requires additional studies.

Photobiomodulation effect on angiogenic proteins produced and released by dental pulp cells.

OBJECTIVE: To verify the photobiomodulation effect on angiogenic proteins produced and released by dental human pulpal fibroblasts (HPFs). MATERIAL AND METHODS: HPFs were irradiated with 660-nm low-level laser at fluences of 2.5 J/cm2 and 3.7 J/cm2. The control group was not irradiated. MTT, crystal violet, and ELISA assays respectively verified viability, proliferation, and angiogenic protein (supernatant/lysate) at 6 h, 12 h, and 24 h after photobiomodulation. Capillary-like structure formation assay verified functional role. Two-way ANOVA/Tukey's test and ANOVA/Bonferroni's multiple comparisons test respectively verified cell viability/proliferation and intragroup and intergroup comparisons of protein synthesis (p < 0.05). RESULTS: Irradiated and non-irradiated HPFs showed statistically similar cell viability and proliferation pattern. Intragroup comparisons showed similar patterns of protein synthesis for all groups: VEGF-A, VEGF-C, and vascular endothelial growth factor receptor 1 (VEGFR1) increased significantly in the supernatant, while FGF-2 and VEGF-A increased significantly in the lysate. The lower fluence significantly increased BMP-9 (6 h) in the supernatant and VEGFR1 (6 h and 12 h) and VEGF-D (24 h) in the lysate, while the higher fluence significantly increased BMP-9 (6 h) in the supernatant and VEGFR1 (12 h) in the lysate. Regardless of the time, both fluences statistically downregulated placental growth factor (PLGF) and PDGF secretion. Both fluences statistically decreased VEGF-A secretion (24 h) and PLGF production (6 h). CONCLUSION: Photobiomodulation produced stimulatory effects on angiogenic protein secretion by pulp fibroblasts. In terms of photobiomodulation, over time, both fluences significantly increased the secretion of VEGF-A, VEGF-C, and VEGFR1 and significantly upregulated BMP-9 (6 h) in the supernatant; for capillary-like structure formation, the fluence of 2.5 J/cm2 was better than the fluence of 3.7 J/cm2. CLINICAL RELEVANCE: This study results addressed effective photobiomodulation parameters tailored for pulp angiogenesis.