Digital measurement of deciduous tooth dimensions in China: A cross-sectional survey

OBJECTIVE

Crown dimensions data of deciduous teeth hold anthropological, forensic, and archaeological value. However, such information remains scarce for the Chinese population. This multi-center study aimed to collect a large sample of deciduous crown data from Chinese children using three-dimensional measurement methods and to analyze their dimensions.

DESIGN

A total of 1592 children's deciduous dentition samples were included, and the sample size was distributed according to Northeast, North, East, Northwest, Southwest and South China. Digital dental models were reconstructed from plaster dental models. Independent sample t test, paired t test, principal component analysis (PCA), and factor analysis (FA) were used to analyze the tooth crown dimensions.

RESULT

18,318 deciduous teeth from 1592 children were included. Males exhibited slightly larger values than females. The range of sexual dimorphism percentages for each measurement was as follows: mesiodistal diameter (0.40-2.08), buccolingual diameter (0.13-2.24), and maxillogingival diameter (0.48-3.37). The FA results showed that the main trend of crown dimensions changes was the simultaneous increase or decrease in mesiodistal diameter, buccolingual diameter and maxillogingival diameter in three directions.

CONCLUSION

This is the first large-scale survey of deciduous tooth crown dimensions in China, which supplements the data of deciduous tooth measurement and provides a reference for clinical application.

Deciduous pulp tissue implantation into the root canal of mandibular incisor resulted in pulp revascularization: a case report with a 5-year follow-up

To explore a new method to implant deciduous tooth pulp into the canal of young permanent teeth with necrotic pulps and apical periodontitis for the regenerative endodontic treatment of tooth no: 41 in a 7-year-old male. Briefly, 1.5% Sodium Hypochlorite (NaOCl) irrigation and calcium hydroxide-iodoform paste were used as root canal disinfectant at the first visit. After 2 weeks, the intracanal medication was removed, and the root canal was slowly rinsed with 17% Ethylene Diamine Tetraacetic Acid (EDTA), followed by flushing with 20 mL saline and then drying with paper points. Tooth no: 72 was extracted, and its pulp was extracted and subsequently implanted into the disinfected root canal along with induced apical bleeding. Calcium hydroxide iodoform paste was gently placed over the bleeding clot, and after forming a mineral trioxide aggregate (MTA) coronal barrier, the accessed cavities were restored using Z350 resin composite. The root developments were evaluated via radiographic imaging at 6 months, 1 year and 5 years after treatment. Imaging and clinical analysis showed closure of the apical foramen, thickening of the root canal wall, and satisfactory root length growth. Autologous transplantation might be useful to regenerate dental pulp in necrotic young permanent teeth.

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.

Performance of near-infrared light transillumination in the detection of occlusal caries lesions in deciduous teeth

BACKGROUND

This study compared the performance of near-infrared light transillumination (NILT; DIAGNOcam [DC]) in detecting occlusal caries lesions in deciduous molars with the performance of the International Caries Detection and Assessment System (ICDAS), digital radiographic method (RX) and laser fluorescence (DIAGNOdent pen [LFpen]).

METHODS

Fifty-seven extracted deciduous molars with no frank cavitation caries lesions were selected. One site per tooth was evaluated twice each by two examiners using all methods. Then, a histological examination was performed using a stereomicroscope. The performance of the methods was assessed with respect to two thresholds: D1 (all visible caries lesions affecting enamel) and D3 (caries lesions extended into dentin).

RESULTS

A weighted kappa and intraclass correlation coefficients were calculated for intra- and inter-observer reproducibilities, varying from 0.31 (RX) to 0.89 (LFpen). The intra-observer reproducibility at D1 and D3 thresholds varied from 0.51 (ICDAS) to 0.85 (DC) and from 0.30 (ICDAS) to 1.00 (RX), respectively. The inter-observer reproducibility varied from 0.28 (RX) to 0.47 (DC) and from 0.22 (LFpen) to 0.75 (DC), respectively. At the D1 threshold, higher sensitivity and accuracy were found for LFpen (0.76/0.71) and ICDAS (0.65/0.66); and higher specificities were found for RX (0.94), DC (0.79), and ICDAS (0.71). At the D3 threshold, all methods exhibited lower sensitivities (0.13-0.35) and higher specificity, accuracy, and area under the ROC curve values (0.70-1.00). All methods showed a correlation with histological results, especially for ICDAS and DC.

CONCLUSIONS

NILT technology (DC) and LFpen exhibited similar performance for the detection of occlusal caries lesions in deciduous molars when compared with ICDAS criteria.

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.

The effect of silver diamine fluoride on the bond strength of glass ionomer to the enamel of primary teeth

Background

Dental caries is a disease which is caused by the acidic by-products of the metabolic processes of dental plaque. Silver components are one of the clinical solutions to prevent caries. This study aimed to investigate the effect of silver diamine fluoride (SDF) application on the shear bond strength of glass ionomer to primary teeth enamel.

Materials and Methods

In this in vitro study, a total of 48 anterior sound primary teeth were randomly divided into four groups (n = 12). The control group (G1) consisted of healthy primary teeth, and the three experimental groups (G2-G4) were composed of demineralized primary teeth. The second group did not undergo SDF treatment, the third group underwent SDF treatment, and the fourth group underwent SDF treatment plus polishing. Glass ionomer cylinders were bonded to all specimens and subsequently tested by a universal testing machine to measure the glass ionomer shear bond strength. The type of fracture was examined by a stereomicroscope. Data analysis was carried out using the SPSS 22 statistical software. Data were analyzed by one-way analysis of variance and posthoc Tukey tests (α =0.05).

Results

The mean shear bond strength of the glass ionomer was significantly higher in the control group than in the other three groups (P < 0.05). The mean shear bond strength of glass ionomer was significantly higher in the SDF-treated group than in the non-SDF treated and SDF-treated and polished groups (P < 0.05).

Conclusion

Although the glass ionomer bond strength to sound enamel was higher than other groups by a significant margin, the application of SDF increases the shear bond strength of the glass ionomer to remineralized white spot enamel in primary teeth.

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.

Dentists' Self-evaluated Ability in Diagnosing and Updating About Pulpotomy

OBJECTIVE

This study aimed to self-evaluate the knowledge of different dental professionals' profiles in Brazil on diagnosing and indicating pulpotomy in primary teeth and how these groups updated on this theme.

METHODS

Three groups (G1: professors, G2: specialists, and G3: professionals) answered an online questionnaire containing 20 questions and returned 416 questionnaires. Data were subjected to Chi-square associative tests and t tests, with P < .05.

RESULTS

G1 and G2 reported to indicate pulpotomy, highlighting the tendency of these groups towards seeking updates on this subject. All 3 groups used academic materials for updating. However, G2 had a high demand for updates through congresses, whilst G3 had a high demand for updates through social media (Google and Google Scholar). The most cited indication by G1 and G2 was "accidental pulp exposure" and by G3 was "teeth with extensive carious lesions that have involved the pulp with radiographic confirmation." All 3 groups opted for pulpotomy to keep the tooth in the arch. Thus, G1 and G2 are the groups who are more updated on the subject, using mainly academic materials, which can be associated with the fact that such groups indicated pulpotomy in primary teeth. The lower interest in searching about pulpotomy in G3 can be understood as a nonclinical application of the topic for this group.

CONCLUSIONS

Professionals who work directly with paediatric dentistry (professors or specialists) felt more capable of diagnosing and treating cases of pulpotomy. In addition, most of the professionals used scientifically based sources for getting information and actualisation on the subject of pulp therapies.

Factors associated with the survival of primary maxillary anterior teeth after intrusive luxation: a retrospective longitudinal study

PURPOSE

To evaluate the survival rate of primary maxillary anterior teeth following intrusive luxation and identify associated factors.

METHODS

A retrospective longitudinal study was conducted at a primary dental trauma centre using 88 dental records of children with intrusive luxation between 2007 and 2018. The variables of interest were time the tooth remained in the alveolus, degree of intrusion, accentuated overjet, lip protection, visible plaque, compromised germ of the permanent successor, clinical signs of infectious and inflammatory processes, endodontic treatment, pulp canal obliteration, sex, age at the time of trauma, family income, mother's schooling, and immediate care. Descriptive, bivariate, and Cox regression analyses were performed (p < 0.05; 95% CI).

RESULTS

The 88 dental records of children with intrusive luxation included 128 teeth. Survival rate throughout the follow-up period was 65.6% (n = 84). Age older than three years and eight months (HR 2.28; 95% CI 1.04-4.99; p = 0.039), the development of an infectious process (HR 3.51; 95% CI 1.39-8.86; p = 0.008), development of an inflammatory process (HR 2.35; 95% CI 1.17-4.71; p = 0.016) and compromised germ of the permanent successor (HR 4.38; 95% CI 1.99-9.61; p < 0.001) were associated with a lower survival rate of intruded primary maxillary anterior teeth.

CONCLUSION

The survival rate during the follow-up period of intruded primary maxillary anterior teeth was considered high. A significantly lower survival rate was associated with age, the occurrence of an infectious process and inflammatory process, and the compromised germ of the permanent successor.

Cystic lesion between a deciduous tooth and the succeeding permanent tooth: a retrospective analysis of 87 cases

Objectives

The purpose of this study is to investigate the characteristics of dentigerous and radicular cysts that occur between deciduous and succeeding permanent teeth and to propose considerations for differential diagnosis of cysts at the treatment planning stage in the outpatient clinic.

Materials and Methods

A total of 87 patients with a cystic lesion located between a deciduous tooth and the succeeding permanent tooth participated in the study. Twelve variables were analyzed to diagnose such a cyst. For data analysis, Fisher's exact test was used to determine the statistical significance of the variables.

Results

Of the total 87 patients who participated in this study, 69 were diagnosed with dentigerous cysts and 18 were diagnosed with radicular cysts. Seven of the 12 differential factors analyzed in this study were statistically significant: age, location, symptoms, dental caries, endodontic treatment, delayed eruption, and size.

Conclusion

Several criteria can be considered for diagnosis of dentigerous cysts or radicular cysts. Age, location, presence of symptoms and dental caries, previous endodontic treatment, cystic size, and delayed eruption of impacted permanent teeth are reliable factors that should be considered when diagnosing dentigerous and radicular cysts.

Biological characteristics and pulp regeneration potential of stem cells from canine deciduous teeth compared with those of permanent teeth

BACKGROUND

Clinical studies have demonstrated that dental pulp stem cells isolated from permanent teeth (PT-DPSCs) are safe and efficacious for complete pulp regeneration in mature pulpectomized permanent teeth with complete apical closure. Moreover, dental pulp stem cells from deciduous teeth (DT-DPSCs) have also been shown to be useful for pulp regenerative cell therapy of injured immature permanent teeth. However, direct comparisons of the pulp regenerative potential of DT-DPSCs and PT-DPSCs from the same individual have not been performed. This study aimed to compare the differences in stem cell properties and pulp regenerative potential of DT-DPSCs and PT-DPSCs of identical origin.

METHODS

DT-DPSCs and PT-DPSCs were isolated from the same individual dogs at 4 months and 9 months of age, respectively. The expression of cell surface antigen markers, proliferation and migration activities, and gene expression of stem cell markers, angiogenic/neurotrophic factors and senescence markers were compared. The effects of conditioned medium (CM) derived from these cells on cellular proliferation, migration, angiogenesis, neurite outgrowth and immunosuppression were also compared. Autologous transplantation of DT-DPSCs or PT-DPSCs together with G-CSF was performed to treat pulpectomized teeth in individual dogs. The vascularization and reinnervation of the regenerated pulp tissues were qualitatively and quantitatively compared between groups by histomorphometric analyses.

RESULTS

The rates of positive CXCR4 and G-CSFR expression in DT-DPSCs were significantly higher than those in PT-DPSCs. DT-DPSCs migrated at a higher rate with/without G-CSF and exhibited increased expression of the stem cell markers Oct3/4 and CXCR4 and the angiogenic factor VEGF and decreased expression of the senescence marker p16 than PT-DPSCs. DT-DPSC-derived CM promoted increased cell proliferation, migration with G-CSF, and angiogenesis compared with PT-DPSC-derived CM; however, no difference was observed in neurite outgrowth or immunosuppression. The regenerated pulp tissues in the pulpectomized teeth were quantitatively and qualitatively similar between the DT-DPSCs and PT-DPSCs transplant groups.

CONCLUSIONS

These results demonstrated that DT-DPSCs could be a potential clinical alternative to PT-DPSCs for pulp regenerative therapy. DT-DPSCs can be preserved in an individual cell bank and used for potential future pulp regenerative therapy before the supply of an individual's own sound discarded teeth has been exhausted.

失活剂烧伤致乳磨牙早失及恒牙胚丧失2例

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.

[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.

Prevalence of premature loss of deciduous teeth and its relationship with gender among children from Acapulco, Guerrero: a cross-sectional study

BACKGROUND

Premature loss of deciduous teeth is the exfoliation or extraction before physiological replacement with < 50% or < 75% of the root of the substitute tooth formed or if there is > 1 mm of alveolar bone covering the permanent successor tooth organ. This study aimed to estimate the prevalence of premature tooth loss in children and identify associated factors in a health center in Acapulco, Guerrero.

METHODS

We conducted a cross-sectional study in which we collected information from 109 clinical records of children examined from January 2019 to August 2021. Sociodemographic data of the children and parents were collected: socioeconomic level, non-pathological personal history, and the history of premature deciduous tooth loss. Multivariate analysis to identify factors associated with premature deciduous tooth loss was performed with CIETmap statistical software. Odds ratio (OR) and 95% confidence interval (CI) were calculated to estimate the strength of the association.

RESULTS

The prevalence of premature loss of primary teeth was 40% (43/109). The leading cause was caries (84%, 36/43). The tooth organ with the highest loss occurrence was the lower right second molar (33%, 14/43). Gender was identified as an associated factor, with males having a higher risk of loss (ORa = 2.97; CI95% = 1.33-6.65).

CONCLUSIONS

Our results were similar to those reported in other studies. Strategies aimed at health promotion directed at parents and children should be reinforced.

What is the survival rate of deciduous molars in cases with agenesis of premolar successors? A systematic review

OBJECTIVES

To systematically review the literature on the survival rate of deciduous molars in cases of agenesis of premolar successors.

MATERIALS AND METHODS

Four electronic databases and partial grey literature were searched up to November 2020. The PECOS eligibility criteria included (P) second deciduous molar (E) exposed to agenesis of a premolar successor (O) evaluated by the survival rate in the oral cavity, infraocclusion, and root resorption through (S) observational studies. Risk of bias (RoB) was assessed using the checklists from the Joanna Briggs Institute and the level of evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) tool.

RESULTS

Three studies were included: one with low, one with moderate, and one with high RoB. Synthesis methods included the frequency of persistent deciduous second molars during the follow-up. Approximately 82% to 89% remained in the oral cavity after 5 to 13 years. The incidence of root resorption was 11%, and the infraocclusion was 1 mm. The level of evidence was considered low for each outcome. There was considerable RoB regarding the observational studies and a need for clinical and radiographic monitoring of the deciduous molars.

CONCLUSIONS

Maintaining a deciduous molar in the oral cavity in patients with agenesis of the premolar successor is a viable clinical choice since 82% to 89% of the retained molars evaluated were in good condition over a follow-up ranging from 5 to 13 years. Infraocclusion and root resorption did not seem to increase considerably. The level of evidence was considered low for each outcome.

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.

Bond strength and microleakage of different types of cements in stainless steel crown of primary molar teeth

BACKGROUND

The margin of crown is a significant area for plaque accumulations. Therefore, the ability of the cement to seal the margin is very important. The aim of the present study was to evaluate the bond (retentive) strength, microleakage, and failure mode of four different types of cements in stainless steel crown (SSC) of primary molar teeth.

MATERIALS AND METHODS

In this experimental study, eighty extracted primary molar teeth were divided into two groups of forty teeth to test the microleakage and bond strength. The crowns were cemented according to the manufacturer guidelines with four cement types including self-cure glass ionomer, resin-modified glass ionomer, polycarboxylate, and resin cements. Stereomicroscope and universal testing machine were used to measure the microleakage and bond strength, respectively. For calculating the surface area of crowns, three-dimensional scanning was used. Furthermore, the failure mode was examined after the bond strength test. The cements surfaces and the tooth-cement interfaces were evaluated using scanning electron microscopy (SEM). The obtained values were analyzed using SPSS-23 software through Shapiro-Wilk and one-way analysis of variance tests. Means, standard deviations, medians, and interquartile ranges were calculated. P < 0.05 was considered as statistically significant in all analyses.

RESULTS

Significant differences between microleakage (P = 0.001) and failure mode (P = 0.041) of the four types of cements were obtained. However, the mean bond strengths of the four groups did not differ significantly (P = 0.124). The obtained SEM images confirmed the results of bond strength and microleakage.

CONCLUSION

Resin cement and resin-modified glass ionomer, respectively, showed superior properties and are recommended for use in SSCs of primary molar 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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01683-0.

Relationship of pH and the viscosity of five different iron supplements with the absorption of iron ions and enamel discoloration in the anterior primary teeth (an in vitro study)

BACKGROUND

Various iron drops are prescribed to children to prevent iron-deficiency anemia. The current study aimed to evaluate and compare the physicochemical profile of iron drops and the effect of these medicines on the color of primary teeth.

MATERIALS AND METHODS

On the commencement of this experimental study, the pH and viscosity of five types of iron drops were measured. For the purpose of the current study, sixty healthy anterior deciduous teeth were provided; thereafter, they were assigned to five groups and then exposed to iron drops. The color and color difference of each specimen were measured by VİTA Easyshade Compact after 2 weeks. The amount of absorbed iron was determined by atomic absorption. The data were analyzed using two-way ANOVA and Tukey's test (P < 0.05).

RESULTS

As evidenced by the obtained results, all medications demonstrated acidic pH and discoloration. The viscosity values of iron drops were reported to be within the range of 2.07-33.58 cP. Based on the results of Pearson's correlation coefficient test, discoloration showed a correlation with pH and atomic absorption (P < 0.05).

CONCLUSION

Analyzed iron drops displayed low pH and discoloration higher than 3.3 which can be easily distinguished with naked eyes. Medicine labels should include warning statements on the feasibility of dental discoloration and erosion.

Comparison of nerve fibers in the deciduous first and second molar teeth: an in vitro study

INTRODUCTION

Sensory nerves of the tooth pulp have been evolved in both deciduous and permanent teeth for conducting possible damages to the teeth. Although it has been reported that the deciduous tooth's pulp is histologically similar to permanent teeth, the difference in the density of nerves between the first and second deciduous molars has been reported in no studies.

AIM

The aim of the study was to investigate the histological assay of pulpal nerves and assess the relationship between diameter and density of nerve fibres in the first and second deciduous molar teeth.

MATERIALS AND METHODS

In this in vitro study, 15 deciduous first and 16 deciduous second extracted from molar teeth belonging to children aged from 5 to 8 years were studied. After fixation, the decalcified teeth were sectioned and then stained with silver solution and calcitonin gene-related peptide (CGRP) antibody. The mean diameter of myelinated fibres, un-myelinated fibres, and density of peripheral network fibres of dental pulp were examined.

RESULTS

The results showed that the mean diameter of myelinated and non-myelinated fibres and density of nerve fibres were significantly more in the second molars (4.269, 2.328 µm, 2.6 fibres per unit area) compared to the first molar teeth (3.793, 2.093 µm, 1.8 fibres per unit area) (P < 0.032, 0.019, 0.003, respectively). An important finding in this study, which is reported for the first time, is the presence of fatty cells (adipocytes) in pulp tissue of some of the first deciduous molars as well as the second molars.

CONCLUSIONS

Based on the results of the current study, differences between nerve fibres of first and second molar teeth are significant. It could be concluded that the less sensitivity to pain of the first deciduous molars compared with the second deciduous molars, is due to the lower nerve density of this tooth.

Efficacy of silver diamine fluoride and sodium fluoride in inhibiting enamel erosion: an ex vivo study with primary teeth

PURPOSE

To assess the efficacy of silver diamine fluoride (SDF) and sodium fluoride (NaF) in inhibiting enamel erosion in primary teeth.

METHODS

80 primary canine teeth were immersed for 24 h in 2% NaF, 10% SDF, or distilled water. Afterward, some of them underwent a 10-min acid challenge using either 1% or 10% citric acid while others did not. Specimens selected for negative controls were immersed in distilled water but not exposed to the acids, whereas those selected for positive controls were not only immersed in distilled water, but also exposed to the acids. Following, 3-mL samples were collected for calcium and phosphorus analysis by an atomic emission spectrometer.

RESULTS

1% acid caused higher phosphorus loss in the positive control group than in the others (no differences between them). Regarding 10% acid, the SDF group showed lower phosphorus loss compared to the positive control and NaF groups. From calcium loss analysis, SDF and NaF groups presented no significant difference when compared to the positive control groups after both acidic challenges.

CONCLUSION

Considering phosphorus loss values, 10% SDF seems to be effective in inhibiting enamel erosion after 1% and 10% citric acid challenges, whereas 2% NaF only after 1% citric acid challenge. Regarding calcium loss values, both fluoride agents seem to have no impact on inhibiting enamel erosion after 1% and 10% citric acid challenges.

Effect of silver diammine fluoride on micro-ecology of plaque from extensive caries of deciduous teeth - in vitro study

Background

The mechanism of action of silver diammine fluoride (SDF) on plaque micro-ecology is seldom studied. This study investigated micro-ecological changes in dental plaque on extensive caries of deciduous teeth after topical SDF treatment.

Methods

Deciduous teeth with extensive caries freshly removed from school children were collected in clinic. Unstimulated saliva collection and initial plaque sampling were done before tooth extraction, then each caries was topically treated with 38% SDF in vitro. After intervention, each tooth was stored respectively in artificial saliva at 37 °C. Repeated plaque collections were done at 24 h and 1 week post-intervention. Post-intervention micro-ecological changes including microbial diversity, microbial metabolism function as well as species correlations were analyzed and compared after pyrosequencing of the DNA from the plaque sample using Illumina MiSeq platform.

Results

After SDF application, microbial diversity decreased (P > 0.05), although not statistically significant. Microbial community composition post-intervention was noticeably different from that of supragingival and pre-intervention plaque as well as saliva. At 1 week post-intervention, the relative content of Pseudomonas, Fusobacterium and Pseudoramibacter were higher than before, while most of the other bacteria were reduced, although the changes were not statistically significant (P > 0.05). The inter-microbial associations became more complex, much more positive associations among survived bacteria were observed than negative ones. COG function classification diagram showed carbohydrate transportation and metabolic functions in the plaque were significantly reduced at 24 h and 1 week post-intervention.

Conclusions

SDF has extensive antimicrobial effect on dental plaque, which may reduce carbohydrate metabolism in dental plaque and help promote new balance of the plaque flora.

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.

Effect of three silver diamine fluoride application protocols on the microtensile bond strength of resin-modified glass ionomer cement to carious dentin in primary teeth

BACKGROUND

Use of silver diamine fluoride (SDF) after selective caries excavation can arrest the further progress of the carious lesion. Application of potassium iodide (KI) can reduce the staining due to SDF.

AIM

The aim of the study was to evaluate the effect of the application of SDF, with and without acid etching and KI on the bond strength of resin-modified glass ionomer cement (RMGIC) to the carious dentin of primary teeth.

MATERIALS AND METHODS

In thisin vitro study, caries was induced on the occlusal surface by inoculating Streptococcus mutans strain in 36 extracted primary molars. The teeth were divided into four groups (n = 9), and the following treatments were done to the carious dentin prior to final restoration with RMGIC: Group I: 10% polyacrylic acid conditioner, Group II: 38% SDF, Group III: 37% phosphoric acid etchant followed by 38% SDF, and Group IV: 37% phosphoric acid etchant followed by 38% SDF and 10% potassium iodide solution. The microtensile bond strength was measured using universal testing machine. Failure modes were recorded using a scanning electron microscope.

RESULTS

There was no significant difference in microtensile bond strengths between the groups (P = 0.665), with the highest value seen in Group III.

CONCLUSIONS

Application of SDF with or without acid etching and KI does not affect the bond strength of RMGIC to carious dentin of primary teeth.

Method for Evaluating Neuromodulatory Properties of Dental Pulp Stem Cell as an In Vitro Model for Parkinson's Disease

Several research groups have utilized dental pulp stem cells for numerous studies as treatment modality for Parkinson's disease (PD). However, the roles of dental pulp stem cells in governing the Parkinson's disease inflammatory microenvironment remain to be evaluated. In this article, we elaborate the method where we can investigate the effects of dental pulp stem cells on neurons and microglia in an in vitro inflammatory microenvironment.

Does photobiomodulation change the synthesis and secretion of angiogenic proteins by different pulp cell lineages?

This study aimed to compare the synthesis and secretion of VEGF-A, VEGF-C, VEGF-D, VEGFR1, VEGFR2, and FGF-2 between pulp fibroblasts from human primary teeth (HPF) and stem cell from human deciduous teeth (SHED) before and after photobiomodulation. HPF were obtained from explant technique and characterized by immunohistochemistry, while SHED were obtained from digestion technique and characterized by flow cytometry. HPF (control group) and SHED were plated, let to adhere, and put on serum starvation to synchronize the cell cycles prior to photobiomodulation. Then, both cell lineages were irradiated with 660-nm laser according to the following groups: 2.5 and 3.7 J/cm². MTT and crystal violet assays respectively verified viability and proliferation. ELISA Multiplex Assay assessed the following proteins: VEGF-A, VEGF-C, VEGF-D, VEGFR1, VEGFR2, FGF-2, at 6, 12, and 24 h after photobiomodulation, in supernatant and lysate. Two-way ANOVA/Tukey test evaluated cell viability and proliferation, while angiogenic production and secretion values were analyzed by one-way ANOVA (P < .05). Statistically similar HPF and SHED viability and proliferation patterns occurred before and after photobiomodulation (P > .05). HPF exhibited statistically greater values of all angiogenic proteins than did SHED, at all study periods, except for FGF-2 (supernatant; 12 h); VEGFR1 (lysate; non-irradiated; 12 h); and VEGFR1 (lysate; non-irradiated; 24 h). Photobiomodulation changed the synthesis and secretion of angiogenic proteins by HPF. HPF produced and secreted greater values of all tested angiogenic proteins than did SHED before and after irradiation with both energy densities of 2.5 and 3.7 J/cm².

Assessment of the Silver Penetration and Distribution in Carious Lesions of Deciduous Teeth Treated with Silver Diamine Fluoride

The aim of this study was to determine the effects of 38% silver diamine fluoride (SDF) on carious lesions of human deciduous teeth. Ten extracted deciduous incisors with caries were collected and treated with SDF. After the treatment, the teeth were sectioned through the center of the carious lesion. The extent of sliver precipitation was examined using quantitative backscattered electron scanning electron microscopy (qBSE-SEM), energy-dispersive X-ray spectroscopy (EDX), and micro-computed tomography (micro-CT). The qBSE-SEM images revealed that the silver particles could penetrate through the pellicle complex, along with the rod sheaths into the demineralized enamel rods and the dentinal tubules, and form silver-enriched barriers surrounding the carious lesions at depths up to 2,490.2 μm (mean 744.7 ± 448.7 μm) within the dentinal tubules of the carious lesions, but less likely in the sound enamel. The EDX spectrum analysis revealed that carbon, oxygen, phosphorus, chlorine, silver, and calcium were the main elements detected in the lesions treated with SDF. Additionally, sodium, magnesium, aluminum, silicon, zinc, sulfur, and fluorine were detected as the minor elements within the SDF precipitation "zone." The micro-CT analysis further showed that in the deep cavitated lesions, the silver precipitation could be observed in the pulp chamber. These findings provide new evidence defining the SDF mode of action for arresting caries and suggest that the application of a highly concentrated SDF solution on deciduous teeth should be used with caution for various carious lesions.

Comparison of in vitro properties of periodontal ligament stem cells derived from permanent and deciduous teeth

Background. Stem cells have contributed to the development of tissue-engineered-based regenerative periodontal therapies. In order to find the best stem cell sources for such therapies, the biologic properties of stem cells isolated from periodontal ligaments (PDL) of deciduous (DePDLSC) and permanent (PePDLSC) teeth were comparatively evaluated. Methods. PDL stem cells were isolated from six sound fully erupted premolars and six deciduous canines of healthy subjects. In vitro biologic characteristics such as colony formation, viability, stem cell marker identification and osteogenic differentiation (using alkaline phosphatase analysis and Alizarin red staining) were comparatively assessed using one-way ANOVA and post hoc Tukey tests using SPSS 13.0. Results. Stem cell populations isolated from both groups were CD105+ and CD90+ and CD45‒. No statistically significant differences were found in stem cell markers, colony formation and viability. Both groups were capable of osteogenic differentiation. However, alkaline phosphatase activity test showed a statistically significant difference, with PePDLSC exhibiting higher alkaline phosphatase activity (P=0.000). No statistically significant difference was seen in quantitative alizarine red staining (P=0.559). Conclusion. Mesenchymal stem cells of PDL could successfully be isolated from permanent and deciduous teeth. A minor difference was observed in the osteogenic properties of the two cell types, which might affect their future clinical applications.

Assessment of facultative anaerobes from the root canals of deciduous molars: An in vivo study

Background. The current research aimed to assess the prevalence of facultative anaerobes isolated from the root canals of deciduous molars.

Methods. The present research enrolled 60 children in the 6‒9-year age group based on clinical and radiographic findings. Under aseptic conditions, access cavities were prepared followed by collection of samples from infected root canals with the help of sterile paper points. The samples thus obtained were subjected for microbial assay.

Results. It was found that Enterococcus faecalis was isolated in 30% of cases, Escherichia coli in 28.4%, Staphylococcus aureus in 25%, α-hemolytic Streptococci in 15% and Proteus mirabilis in 1.6% of cases.

Conclusion. It was concluded from the results of the present study that the root canals of deciduous molars had predominance of facultative anaerobes, confirming its polymicrobial nature. This identification of microbes is crucial as it aids in understanding the pathogenesis of pulpal and periradicular diseases to provide effective antimicrobial irrigation and medicament for endodontic treatment.

Occlusal rehabilitation in patients with congenitally missing teeth-dental implants, conventional prosthetics, tooth autotransplants, and preservation of deciduous teeth-a systematic review

Background

Implant patients with congenitally missing teeth share some common charateristics and deserve special attention.

Methods

The PICO question was “In patients with congenitally missing teeth, does an early occlusal rehabilitation with dental implants in comparison to tooth autotransplants, conventional prosthetics on teeth or preservation of deciduous teeth have better general outcomes in terms of survival, success and better patient centered outcomes in terms of quality of life, self-esteem, satisfaction, chewing function?”

After electronic database search, a total of 63 relevant studies were eligible, of which 42 qualified for numerical data synthesis, 26 being retrospective studies. A data synthesis was performed by weighted means for survival/success/annual failure rates.

Results

The mean survival of implants was 95.3 % (prosthesis survival 97.8 %), autotransplants 94.4 %, deciduous teeth 89.6 %, and conventional prostheses 60.2 %. The implant survival in children, adolescents, and adults was 72.4, 93.0, and 97.4 %. Annual failure rates of implants 3.317 %, autotransplants 1.061 %, deciduous teeth 0.908 %, and conventional prostheses 5.144 % indicated better results for natural teeth and more maintenance needs for the both prosthetic treatments. The mean OHIP score was 27.8 at baseline and a mean improvement of 14.9 score points was reported after implant prosthetics. The mean satisfaction rates were 93.4 (implants), 76.6 (conventional prostheses), 72.0 (autotransplants), and 65.5 % (orthodontic space closure).

Conclusions

In synopsis of general and patient-centered outcomes, implants yielded the best results, however, not in children <13 years. Autotransplants and deciduous teeth had low annual failure rates and are appropriate treatments in children and adolescents at low costs. Conventional prosthetics had lower survival/success rates than the other options. Due to heterogeneity and low number of studies, patient-reported outcomes in this review have to be interpreted with caution.

Evaluation of pulpal response of deciduous teeth after direct pulp capping with bioactive glass and mineral trioxide aggregate

Aim:

The aim of this study was to evaluate the pulpal response of primary teeth after direct pulp capping (DPC) with two biocompatible materials namely mineral trioxide aggregate (MTA) and bioactive glass (BAG).

Settings and Design:

This study was a randomized clinical trial.

Materials and Methods:

A total of 22 healthy primary canine teeth scheduled for extraction for orthodontic reasons were selected. The teeth were divided into two groups of 11 and underwent DPC. The exposure sites were randomly capped with MTA or BAG in the two groups. After 2 months, the teeth were extracted and prepared for histopathologic evaluation.

Statistical Analysis:

The data were analyzed using Fisher's exact test.

Results:

In the BAG group, inflammation was seen in three patients; internal resorption and abscess were not seen at all. In the MTA group, inflammation was seen in one patient and internal resorption and abscess were not seen in any patient. Fisher's exact test showed no significant difference between the two groups (P > 0.05). Dentinal bridge formation was noted in five patients in the BAG group and six patients in the MTA group. No significant difference was observed between the BAG and MTA groups using Chi-square analysis (P = 0.67).

Conclusion:

Based on the results of this study, MTA and BAG can be used for DPC of primary teeth.

Rare presentation of adenomatoid odontogenic tumor in a pediatric patient: a case report

The adenomatoid odontogenic tumor (AOT) is a painless benign tumor with slow growth, usually asymptomatic. It has three variants: follicular, extrafollicular, and peripheral. In the follicular type, the tumor is associated with an impacted tooth, and maxillary canines are the most frequently affected. Association with primary teeth is very rare. Treatment consists essentially in a total lesion enucleation. The objective of this paper is to present the clinical case of a 7-year-old female patient with an adenomatoid odontogenic tumor associated with the crown of the left lower deciduous canine (73), dislodging it to the mandibular base and consequently shifting and also impacting the permanent lower canine (33). The lesion was treated with careful enucleation, preserving the permanent canine, which then had its eruption path released favoring its migration to an ideal position.

Choice of Feeders Is Important When First Establishing iPSCs Derived From Primarily Cultured Human Deciduous Tooth Dental Pulp Cells

Feeder cells are generally required to maintain embryonic stem cells (ESCs)/induced pluripotent stem cells (iPSCs). Mouse embryonic fibroblasts (MEFs) isolated from fetuses and STO mouse stromal cell line are the most widely used feeder cells. The aim of this study was to determine which cells are suitable for establishing iPSCs from human deciduous tooth dental pulp cells (HDDPCs). Primary cultures of HDDPCs were cotransfected with three plasmids containing human OCT3/4, SOX2/KLF4, or LMYC/LIN28 and pmaxGFP by using a novel electroporation method, and then cultured in an ESC qualified medium for 15 days. Emerging colonies were reseeded onto mitomycin C-treated MEFs or STO cells. The colonies were serially passaged for up to 26 passages. During this period, colony morphology was assessed to determine whether cells exhibited ESC-like morphology and alkaline phosphatase activity to evaluate the state of cellular reprogramming. HDDPCs maintained on MEFs were successfully reprogrammed into iPSCs, whereas those maintained on STO cells were not. Once established, the iPSCs were maintained on STO cells without loss of pluripotency. Our results indicate that MEFs are better feeder cells than STO cells for establishing iPSCs. Feeder choice is a key factor enabling efficient generation of iPSCs.

Non-invasive sources of cells with primary cilia from pediatric and adult patients

BACKGROUND

Ciliopathies give rise to a multitude of organ-specific pathologies; obtaining relevant primary patient material is useful for both diagnostics and research. However, acquisition of primary ciliated cells from patients, particularly pediatric patients, presents multiple difficulties. Biopsies and blood samples are invasive, and patients (and their parents) may be reluctant to travel to medical centers, especially for research purposes. We sought to develop non-invasive methods of obtaining viable and ciliated primary cells from ciliopathy patients which could be obtained in the home environment.

FINDINGS

We introduce two methods for the non-invasive acquisition of primary ciliated cells. In one approach, we collected spontaneously shed deciduous (milk) teeth from children. Fibroblast-like cells were observed after approximately 2 weeks of culture of fragmented teeth. Secondly, urine samples were collected from children or adults. Cellular content was isolated and after approximately 1 week, renal epithelial cells were observed. Both urine and tooth-derived cells ciliate and express ciliary proteins visible with immunofluorescence. Urine-derived renal epithelial cells (URECs) are amenable to 3D culturing, siRNA knockdown, and ex vivo drug testing.

CONCLUSIONS

As evidence continues to accumulate showing that the primary cilium has a central role in development and disease, the need for readily available and ciliated patient cells will increase. Here, we introduce two methods for the non-invasive acquisition of cells with primary cilia. We believe that these cells can be used for further ex vivo study of ciliopathies and in the future, for personalized medicine.

Carious deciduous teeth are a potential source for dental pulp stem cells

OBJECTIVE

The objectives of this study are to isolate, cultivate, and characterize stem cells from the pulp of carious deciduous teeth (SCCD) and compare them to those retrieved from sound deciduous teeth (SHED--stem cells from human exfoliated deciduous teeth).

MATERIAL AND METHODS

Cells were obtained of dental pulp collected from sound (n = 10) and carious (n = 10) deciduous human teeth. Rate of isolation, proliferation assay (0, 1, 3, 5, and 7 days), STRO-1, mesenchymal (CD29, CD73, and CD90) and hematopoietic surface marker expression (CD14, CD34, CD45, HLA-DR), and differentiation capacity were evaluated.

RESULTS

Isolation success rates were 70 and 80 % from the carious and sound groups, respectively. SCCD and SHED presented similar proliferation rate. There were no statistical differences between the groups for the tested surface markers. The cells from sound and carious deciduous teeth were positive for CD29, CD73, and CD90 and negative for CD14, CD34, CD45, and HLA-DR and were capable of differentiating into osteogenic, chondrogenic, and adipogenic lineages.

CONCLUSION

SCCD demonstrated a similar pattern of proliferation, immunophenotypical characteristics, and differentiation ability as those obtained from sound deciduous teeth. These SCCD represent a feasible source of stem cells.

CLINICAL RELEVANCE

Decayed deciduous teeth have been usually discarded once the pulp tissue could be damaged and the activity of stem cells compromised. These findings show that stem cells from carious deciduous teeth can be applicable source for cell-based therapies in tissue regeneration.

Caries removal in deciduous teeth using an Er:YAG laser: a randomized split-mouth clinical trial

OBJECTIVES

The aim of the present clinical randomized split-mouth study was to evaluate the effectiveness and efficiency of an Er:YAG laser for caries removal in primary molars, microbiological dentin analysis, and clinical restorations after 1 year in 29 children.

MATERIALS AND METHODS

The children's teeth were randomized into two groups: (I) an Er:YAG laser group and (II) a bur preparation group. The efficiency of the treatments (the time necessary for the removal of carious tissue) was evaluated based on the time spent on caries removal in the deciduous molars. The effectiveness (caries removal capacity) of the caries removal was determined by means of a blind test in which the examiner performed a tactile and visual examination of the dentin. Microbiological analysis was performed by counting the Streptococcus mutans and Lactobacillus sp in the remaining dentin. Clinical analysis of restorations was performed using the USPHS method in combination with photographs of restored teeth, 7 days after the restorative procedure and again after 1 year. All cavities were restored with the Adper Single Bond 2/Filtek Z350 system. The obtained data were analyzed with a significance level of 5 %.

RESULTS

The Er:YAG laser was less effective and had the same efficacy as bur preparation during caries removal at the pulpal wall of deciduous molars. In the surrounding walls, bur preparation was the more effective method. Regardless of the method employed, the affected dentin in the pulpal wall had similar amounts of S. mutans and Lactobacillus sp. The restorations were clinically accepted by the USPHS method over a 1-year period.

CONCLUSION

It can be concluded that caries removal with an Er:YAG laser has no influence on the clinical behavior of restorations.

CLINICAL RELEVANCE

Irradiation with an Er:YAG laser is appropriate for caries removal in primary teeth.

Maternal attitudes towards tooth decay in children aged 12-18 months in Pelotas, Brazil

AIM

This was to assess mothers' attitudes towards dental caries in children aged 12-18 months.

METHODS

This study targeted mothers of children aged 12-18 months. Data about demographic and socioeconomic status were collected by interviews with each mother. In addition, the mother was asked about her attitudes regarding caries in her child's primary teeth. A dental examination of each child was also conducted. Chi-square, bivariate, and multiple logistic regression analyses were performed.

RESULTS

A total of 262 mother-child pairs were included, and 18.7 % of the children had dental caries. If a child presented with dental caries in their primary teeth, 93.5 % of the mothers reported that they would take the child to a dentist. Mothers who had only one child and those who had children with dental caries were more likely to report that they did not expect primary dental caries treatment by the dentist.

CONCLUSION

Most mothers reported that they would take their children to a dentist when they presented with dental caries. Despite this positive result, educational measures should continue to be emphasised, especially among mothers of children at a higher risk of caries and among first-time mothers.

Clinical and radiographic evaluation of Portland cement added to radiopacifying agents in primary molar pulpotomies

AIM

This was to evaluate the clinical and radiographic outcomes of Portland cement (PC) added to radiopacifying agents in primary molar pulpotomies.

METHODS

Thirty primary mandibular molars of children aged between 5 and 9 years were randomly assigned to the following groups: PC; PC with iodoform (PC + CHI(3)); PC with zirconium oxide (PC + ZrO(2)) and treated by pulpotomy technique. Clinical and radiographic follow-up assessments were performed at 6, 12 and 24 months. Statistical analysis was performed by Fisher's exact test (P < 0.05).

RESULTS

The clinical and radiographic evaluations showed 100 % success rates, and the results showed no statistically significant difference between groups.

CONCLUSIONS

According to this study, PC added to radiopacifying agents exhibited satisfactory clinical and radiographic results in primary molar pulpotomies.

Treatment outcomes of primary molars direct pulp capping after 20 months: a randomized controlled trial

INTRODUCTION

The aim of this randomized controlled trial was to compare the radiographic and clinical success rates of direct pulp capping (DPC) using ProRoot mineral trioxide aggregate (MTA) or calcium enriched mixture (CEM).

METHODS AND MATERIALS

A total of 42 symptom-free carious vital primary molars (21 pairs) were selected in this split mouth trial and randomly pulpotomized in two experimental groups. Pinpoint pulp exposures were covered by the same blinded operator with MTA or CEM, and then restored by amalgam. Radiographic and clinical successes were evaluated at 20 month follow-up. Data were statistically analyzed using McNemar test.

RESULTS

Nineteen patients were available for 20-month follow-up; only one failed tooth was extracted in the CEM group. All available teeth were symptom-free, however, the final evaluated success rate was 89% in CEM (CI 95%: 0.82-0.96) and 95% in MTA (CI 95%: 0.85-1) groups without statistical difference (P=0.360). Worst case scenario was applied for missing value analysis; assuming that the 2 lost cases in CEM group had failed and the only lost case in MTA group was due to treatment success, as a result the success of CEM and MTA were 81% (CI 95%: 0.72-0.90) and 95% (CI 95%:0.85-1), respectively, with no statistical difference (P=0.078). In the reverse scenario, the success of MTA and CEM were 86% (CI 95%: 0.78-0.94) and 90% (CI 95%: 0.82-0.98), respectively; again with no statistical difference (P=0.479).

CONCLUSION

Effectiveness of MTA and CEM biomaterials for primary molars' DPC was similar; CEM can be a suitable alternative for MTA.

Comparison of the cleaning capacity of Mtwo and Pro Taper rotary systems and manual instruments in primary teeth

Background:

Root canal cleaning is an important step in endodontic therapy. In order to develop better techniques, a new generation of endodontic instruments has been designed. The aim of this study was to compare the effectiveness of manual K-files (Mani Co, Tokyo, Japan) and two rotary systems–Mtwo (Dentsply-Maillefer, Ballaigues, Switzerland) and ProTaper (VDW, Munich, Germany)–for root canal preparation in primary molars.

Materials and Methods:

India ink was injected to 160 mesiobuccal and distal root canals of mandibular primary molars. The teeth were randomly divided into three experimental groups and one control group. In each experimental group, either manual instruments (K-files) or rotary instruments (Mtwo or ProTaper) were used to prepare root canals. After cleaning the canals and clearing the teeth, ink removal was evaluated with a stereomicroscope. Statistical analysis was done with Kruskal–Wallis and Friedman tests.

Results:

There were no significant differences in cleaning efficiency between manual and rotary instruments. Only ProTaper files performed significantly better in the coronal and middle thirds than in the apical third of the root canal.

Conclusion:

Manual K-files and the Mtwo and ProTaper rotary systems showed equally acceptable cleaning ability in primary molar root canals.