OBJECTIVE: The patterning cascade model of crown morphogenesis has been studied extensively in a variety of organisms to elucidate the evolutionary history surrounding postcanine tooth form. The current research is the first to use a large modern human sample to examine whether the crown configuration of lower deciduous and permanent molars aligns with expectations derived from the model. This study has two main goals: 1) to determine if metameric and antimeric pairs significantly differ in size, accessory trait expression, and relative intercusp spacing, and 2) assess whether the relative distance among early-forming cusps accounts for observed variation in accessory cusp expression.
METHODS: Tooth size, intercusp distance, and morphological trait expression data were collected from 3D scans of mandibular dental casts representing participants of the Harvard Solomon Islands Project. Paired tests were utilized to compare tooth size, accessory trait expression, and relative intercusp distance between diphyodont metameres and permanent antimeres. Proportional odds logistic regression was implemented to investigate how the odds of greater accessory cusp expression vary as a function of the distance between early-developing cusps.
RESULTS: Comparing paired molars, significant differences were identified for tooth size and cusp 5 expression. Several relative intercusp distances emerged as important predictors of cusp 6 expression, however, results for cusp 5 and cusp 7 did not match expected patterns. These findings support previous quantitative genetic results and suggest the development of neighboring crown structures represents a zero-sum partitioning of cellular territory and resources. As such, this study contributes to a better understanding of the foundations of deciduous and permanent molar crown variation in humans.

OBJECTIVE: To compare preparation times using manual, rotary, and reciprocating files during pulpectomy treatment of primary molars.
METHODS: This study was an in vitro, randomised, cross-sectional study.
METHODS: The study was performed on 60 extracted human primary mandibular second molars. Only mesiobuccal canals were prepared using one of three preparation techniques; each preparation technique group comprised 20 canals. Canal preparations were performed by a single, skilled operator using stainless-steel (ss) K-files (ISO size 20-35), a ProTaper Gold SX file, and a WaveOne Gold Medium file following glide path preparation. Preparation times were recorded in second (s) with a digital stopwatch.
METHODS: Preparation times were compared using analysis of variance and the Kruskal-Wallis analysis of variance, where appropriate. The level of significance was set at P ≤ 0.05.
RESULTS: The mean preparation time using the ss K-files was significantly longer (186.4 s) than when using the ProTaper Gold SX (29.6 s) or WaveOne Gold Medium files (30.5 s) (P < 0.001). Similar preparation times were recorded when using the ProTaper Gold SX and WaveOne Gold Medium files (P = 0.939).
CONCLUSIONS: Preparation times with the ProTaper Gold SX and WaveOne Gold Medium files were significantly faster than when using the ss K-files to prepare primary tooth root canals for pulpectomy. Similar preparation times were noted when using the rotary and reciprocation instrumentation groups (P > 0.05).

Articular cartilage damage still remains a major problem in orthopedical surgery. The development of tissue engineering techniques such as autologous chondrocyte implantation is a promising way to improve clinical outcomes. On the other hand, the clinical application of autologous chondrocytes has considerable limitations. Mesenchymal stromal cells (MSCs) from various tissues have been shown to possess chondrogenic differentiation potential, although to different degrees. In the present study, we assessed the alterations in chondrogenesis-related gene transcription rates and extracellular matrix deposition levels before and after the chondrogenic differentiation of MSCs in a 3D spheroid culture. MSCs were obtained from three different tissues: umbilical cord Wharton\'s jelly (WJMSC-Wharton\'s jelly mesenchymal stromal cells), adipose tissue (ATMSC-adipose tissue mesenchymal stromal cells), and the dental pulp of deciduous teeth (SHEDs-stem cells from human exfoliated deciduous teeth). Monolayer MSC cultures served as baseline controls. Newly formed 3D spheroids composed of MSCs previously grown in 2D cultures were precultured for 2 days in growth medium, and then, chondrogenic differentiation was induced by maintaining them in the TGF-β1-containing medium for 21 days. Among the MSC types studied, WJMSCs showed the most similarities with primary chondrocytes in terms of the upregulation of cartilage-specific gene expression. Interestingly, such upregulation occurred to some extent in all 3D spheroids, even prior to the addition of TGF-β1. These results confirm that the potential of Wharton\'s jelly is on par with adipose tissue as a valuable cell source for cartilage engineering applications as well as for the treatment of osteoarthritis. The 3D spheroid environment on its own acts as a trigger for the chondrogenic differentiation of MSCs.

This study evaluates the efficacy of 3D-printed band and loop space maintainers (3D-BLSMs) to mitigate concerns caused by early primary tooth loss in children when compared to their conventional equivalents. Over 9 months, 62 participants aged 6 to 12 years participated in a randomized clinical study. This study evaluated their failure rates (de-cementation, debonding, solder breakage, loop breakage, band breakage, and abutment tooth fracture), gingival health, and patient overall satisfaction. Random assignments were made to place the participants in two groups: traditional band and loop space maintainers or the 3D-BLSMs. The findings show that at 9 months, 3D-BLSMs provided significantly higher survival rates (77.4%) than conventional maintainers (51.6%, p < 0.01). Gum inflammation was mild in both groups, highlighting the need for good oral hygiene. In both groups, patient satisfaction exceeded 90%. Although there was some pain at first with 3D-BLSMs, this eventually subsided and aesthetic preferences disappeared. There were no negative consequences noted, and both groups needed ongoing dental treatment. In conclusion, with excellent patient satisfaction in both groups, 3D-printed space maintainers offer greater long-term durability in reducing dental concerns following early primary tooth loss.

BACKGROUND: The black staining effect of silver-containing solutions for use to arrest caries can have a negative aesthetic impact on children and parents. This study aims to assess the staining effects of Silver Diamine Fluoride/Potassium Iodide (SDF/KI), SDF and Nanosilver Fluoride (NSF).
METHODS: Forty-four extracted carious primary molars were collected and randomly divided into four groups (n = 11). The carious tissue in all teeth was removed using a chemo-mechanical caries removal agent with an excavator. After caries removal in all groups, SDF, SDF/KI, and NSF were applied to the different groups, while no solution was applied to the control group. Subsequently, the teeth in all groups were restored with compomer. Color values L*, a* and b* were measured using a spectrophotometer at three time points: immediately after compomer restoration (T0), one week later (T1), and four week later (T2). Changes in brightness (ΔL) and color (ΔE) over time were calculated and comparisons among groups were made.
RESULTS: The SDF solution induced statistically significant black staining (p = 0.013) and a decrease in L* value (p < 0.001) on the compomer material compared to the other groups over time.
CONCLUSIONS: It was observed that SDF/KI has the potential to reduce the black staining effect of SDF, though not entirely. Novel experimental solutions like NSF may offer an alternative to counteract the staining effect of SDF.

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BACKGROUND: The aim of this retrospective study was to determine the long-term clinical and radiographic success of our previous randomized clinical trial and to compare the success of hyaluronic acid, with the widely used formocresol and ferric sulphate agents.
METHODS: This retrospective study is the extension of the 1-year survey of our randomized clinical trial that had compared the effectiveness of a hyaluronic acid pulpotomy over formocresol and ferric sulphate pulpotomies and included clinical and radiographic evaluations with a follow-up period of over 24 months for 44 children who applied to our clinic between May 2019 and September 2019. Long-term clinical and radiographic data were obtained from the periodic files of our department, wherein each tooth\'s file was examined to identify any clinical and radiographic findings. Descriptive statistics and Pearson\'s chi-square tests were used to evaluate the data. Statistical significance was considered as p < 0.05.
RESULTS: The clinical and radiographic success rates of the hyaluronic acid, formocresol, and ferric sulphate groups were not statistically different at > 24 months. None of the teeth in the hyaluronic acid group showed any clinical findings at > 24 months.
CONCLUSIONS: Hyaluronic acid pulpotomies exhibited comparable success rates to formocresol and ferric sulphate materials spanning over 24 months examinations. Because of convenient accessibility and applicability of hyaluronic acid, it may be recommended as a promising alternative medicament for pulpotomy treatments of primary molars. However, further long-term follow-up human studies are needed to better understand the effect of hyaluronic acid on the dental pulp of human primary molars.

BACKGROUND: This manuscript investigates the prevalence, classification, accompanying findings, and treatment modalities associated with infraoccluded primary molars. The aim of this study categorizing primary molars based on the severity of infraocclusion and assessing their respective treatment interventions across different severity groups.
METHODS: The classification, treatment types, accompanying findings, and the condition of succeeding premolars of infraoccluded molars were documented. Chi-square tests, including Fisher\'s Exact Chi-square test, Fisher Freeman Halton Exact Chi-square test, and One Sample Chi-square test, were conducted. The predetermined significance level was less than 0.05.
RESULTS: The study population consisted of 3132 subjects aged 3 to 15 years, with a prevalence of 4.3% for infraocclusion. Infraocclusion typically manifests between 6 and 9 years of age and predominantly affects mandibular primary molars. Treatment interventions varied based on infraocclusion severity, with more invasive procedures required for severe cases. Accompanying findings associated with infraocclusion include adjacent teeth tipping, significant deviation in midline shifts towards the affected side and increased caries. Additionally, succeeding premolar agenesis was observed in 2% of infraoccluded molars, with extraction rates higher in cases where the successor tooth was mesially or distally located.
CONCLUSIONS: The study offers novel insights to dental practitioners concerning the severity and distribution of treatment interventions for infraocclusion. It suggests that more severe cases may necessitate more invasive procedures, with the aim of enhancing patient outcomes through timely intervention and personalized therapeutic strategies.

In the realm of regenerative medicine and therapeutic applications, stem cell research is rapidly gaining traction. Dental pulp stem cells (DPSCs), which are present in both deciduous and permanent teeth, have emerged as a vital stem cell source due to their accessibility, adaptability, and innate differentiation capabilities. DPSCs offer a readily available and abundant reservoir of mesenchymal stem cells, showcasing impressive versatility and potential, particularly for regenerative purposes. Despite their promise, the main hurdle lies in effectively isolating and characterizing DPSCs, given their representation as a minute fraction within dental pulp cells. Equally crucial is the proper preservation of this invaluable cellular resource. The two predominant methods for DPSC isolation are enzymatic digestion (ED) and outgrowth from tissue explants (OG), often referred to as spontaneous growth. This protocol concentrates primarily on the enzymatic digestion approach for DPSC isolation, intricately detailing the steps encompassing extraction, in-lab processing, and cell preservation. Beyond extraction and preservation, the protocol delves into the differentiation prowess of DPSCs. Specifically, it outlines the procedures employed to induce these stem cells to differentiate into adipocytes, osteoblasts, and chondrocytes, showcasing their multipotent attributes. Subsequent utilization of colorimetric staining techniques facilitates accurate visualization and confirmation of successful differentiation, thereby validating the caliber and functionality of the isolated DPSCs. This comprehensive protocol functions as a blueprint encompassing the entire spectrum of dental pulp stem cell extraction, cultivation, preservation, and characterization. It underscores the substantial potential harbored by DPSCs, propelling forward stem cell exploration and holding promise for future regenerative and therapeutic breakthroughs.

BACKGROUND: The survival of ART restorations can be influenced by the choice of the restorative material. The aim of this randomized non-inferiority controlled trial was to compare the 2-year survival rate and cost analysis of two encapsulated glass ionomer cements (GIC) as occlusoproximal restorative materials in primary molars.
METHODS: Children from public schools in Tietê (Brazil), aged 4-8 years with occlusoproximal dentine carious lesions in primary molars were selected and randomly assigned to receive either Equia Forte (EF) or Riva Self Cure (RSC) as restorative materials. Treatment was carried out by two trained final-year dental students in schools following ART premises. Restorations were assessed by a trained and calibrated examiner after 2, 6, 12, 18, and 24 months. The primary outcome was restoration survival after 2 years, analyzed using Kaplan-Meier survival and Cox regression analysis (α = 5%). Professional and materials costs for each group were collected in Brazilian Reais (R$) and converted into US dollars (US$) and analyzed using Monte-Carlo simulation.
RESULTS: A total of 152 children (76 per group) were included in the study, and 121 (79%) were evaluated after 2 years. The overall 2-year restoration survival rate was 39% (EF = 45%; RSC = 32%) with no difference between the groups. The baseline and 2-year total cost of restorations using RSC was lower when compared to EF (incremental cost: US$ 6.18).
CONCLUSIONS: After two years of follow-up, Riva Self Cure shows comparable restoration survival rates to Equia Forte, being more cost-effective in the Brazilian perspective.
BACKGROUND: This randomized clinical trial was registered on ClinicalTrials.Gov - NCT02730000.