Apical Pressure Generated Using Conventional Syringe Irrigation in Immature Teeth—An In Vitro Study

This in vitro study aimed to evaluate apical pressure during irrigant delivery with syringe irrigation in immature teeth with an open apical foramen. Conventional syringe irrigation was performed in a 3D-printed immature incisor. A 5 mL syringe combined with 25 G and 30 G cannulas was used. Open-ended and side-vented needle tip designs were assessed. Cannulas were placed at tooth length (TL), TL −1 mm, TL −2 mm, and TL −4 mm. The syringe plunger was moved with a force of 10 N, 20 N, 40 N, and 80 N to simulate clinical conditions. A pressure sensor measured periapical pressures during irrigation. Each experiment was repeated 10 times. Data were analyzed descriptively (maximum, mean, standard deviation, 95% CI) with the critical threshold indicative of extrusion set at 7.64 mbar. 30 G cannulas with both needle tip designs never exceeded the threshold at any TL with a plunger force of 10–40 N. At 80 N, 30 G open-ended cannulas exceeded the threshold in 10%, 30 G side-vented in 20–60% of the measurements. At any TL, 25 G open-ended cannulas and 25 G side-vented cannulas never crossed the threshold with forces of 10–20 N and 10 N, respectively. Consequently, 30 G cannulas with both designs can be recommended for irrigant delivery in immature teeth. 25 G cannulas ought to be used with caution.

Estimating Chronological Age by Dental Measurements on the Periapical Radiographs of an ‎Iranian Adult Population

Background: This study aimed to assess the accuracy of chronological age estimation based on dental measurements made on the Periapical (PA) radiographs of an Iranian adult population. Methods: This study evaluated 90 parallel PA radiographs of sound maxillary canine teeth of 39 males and 51 females. Tooth length, root length, pulp length, pulp width, and root width at points A, B, and C according to Kvaal’s method were measured on PA radiographs using Scanora software. The collected data were analyzed using SPSS. Results: Maximum root width at point A provided the highest accuracy for gender estimation (77.7%). A significant correlation was noted between maximum pulp width at points B and C with age. Besides, a regression formula for age estimation was obtained. Conclusion: Maximum pulp width at points B and C could be used for age estimation in the adult population besides other parameters.

Estimating Chronological Age by Dental Measurements on the Periapical Radiographs in Iranian Adults

Objectives: This study aimed to assess the accuracy of chronological age estimation based on dental measurements made on periapical (PA) radiographs of an Iranian adult population. Materials and Methods: This study evaluated 90 parallel PA radiographs of sound maxillary canine teeth of 39 males and 51 females. Tooth length, root length, pulp length, pulp width and root width at points A, B and C according to the Kvaal’s method were measured on PA radiographs using Scanora software. Data were analyzed using SPSS. Results: Maximum Root width at point A had the highest accuracy for sex estimation (77.7%). A significant correlation was noted between maximum pulp width at points B and C with age and a regression formula for age estimation was obtained. Conclusion: Maximum pulp width at points B and C can be used for age estimation in adult population beside other parameters.

Neonatal line may develop after birth in the Indo-Pacific bottlenose dolphin (Tursiops aduncus)

Studies using teeth to estimate age in marine mammals presume that the neonatal line (NNL) develops at birth. This study of Indo-Pacific bottlenose dolphins (Tursiops aduncus (Ehrenberg, 1833)) is the first to investigate when the NNL appears in odontocete dentine. Two to four teeth were prepared by decalcification, thin-sectioning, and staining for 103 dolphins, including 7 dolphins of known age. Tooth length, prenatal and postnatal dentine and NNL widths were measured. Developmental class (foetus, young neonate, older neonate, <1-year-old calf, 1-year-old calf) was assigned using carcass external features. NNL presence or absence was categorised for individual dolphins. The NNL was absent in a near-term foetus and all except one young neonate and fully formed in 50% of older neonates, whose estimated ages were 1 week to 2 months. It was absent in a known-age dolphin aged 4–7 weeks. NNL width was greater in dolphins less than 1 year old compared with those that were 1 year old. Factors that trigger NNL development are unknown. The present study suggests that the NNL may not be related to birth per se in dolphins, as has been clearly demonstrated in humans. Physiological processes, driven by diet, and behavioural changes during the first few months of postnatal life may be important drivers for NNL formation in odontocetes.

Accuracy of cone beam computed tomography in predicting the linear dimensions of impacted maxillary canines- A clinical study

Background and Objectives: This study was conducted to investigate the accuracy of CBCT by comparing the linear measurements of impacted maxillary canines measured by CBCT scans with physical measurements from digital calipers. Method: 18 patients in the age group of 13 years and above having impacted maxillary canine/s classified as sector III or IVwith complete root formation and willing for surgical extractionwere included. CBCT scan was taken of the quadrant of interest using KODAK 9000 3D Extraoral Imaging System. All linear measurements (mesiodistal width, labiolingual width and total length of tooth) were carried out. After the atraumatic surgical removal of impacted canines, the teeth were collected and the same measurements were made by digital calipers, using the same points as those used for the CBCT scans. The data obtained were subjected to statistical analysis. Results: Intra and inter observer reliability was excellent as coefficient of correlation was above 0.92 for all digital caliper and CBCT measurements. Comparison of intra-examiner CBCT and Digital Caliper methods in measurements of labiolingual width, mesiodistal width and total tooth length by Paired-t test showed no statistically significant difference for labiolingual width and mesiodistal. Conclusion: The labiolingual and mesiodistal tooth width measurements from CBCT scans were accurate and the differences between the digital caliper and CBCT measurements were not statistically significant. Total tooth length measurements derived from the CBCT images were less accurate compared with the actual measurements.

Growth hormone receptor gene is related to root length and tooth length in human teeth

ABSTRACT Objectives: To examine the relationship between tooth length and growth hormone receptor (GHR) gene variants in a healthy Japanese population. Materials and Methods: The subjects consisted of 193 Japanese adults (69 men, 124 women), aged 13 to 56 years. Genomic DNA was extracted from saliva and genotyped GHR rs6184 and rs6180 variants using the Taqman genotyping. Computed tomography (CT) images were acquired using a dental cone-beam CT scanner and reconstructed using open-source OsiriX medical image processing software. The maxillary (upper; U) and mandibular (lower, L) central incisors (1), lateral incisors (2), canines (3), first premolars (4), second premolars (5), first molars (6), and second premolars (7) were evaluated. Teeth were assessed for crown height (CH), root length (RL), overall tooth length (C+R), and crown to root ratio (C/R). The relationships between GHR variants and CH, RL, C+R, and C/R were statistically examined. Results: The GHR variant rs6184 was associated with the root lengths and tooth length for the upper and lower lateral incisors and upper canines (U2 RL; U3 RL, C+R; L2 RL [P &lt; .05]). Conclusions: The results indicate that the GHR rs6184 variant is associated with tooth length and ratio dimensions in a Japanese cohort. Further studies utilizing a larger sample size are needed to confirm this finding.