Tooth Morphology Overview

This chapter provides an overview of tooth morphology, including a review of tooth anatomy, tooth development, and associated nomenclature and numbering systems. First, basic tooth morphology nomenclature is presented. Next, various tooth numbering systems are described and discussed, and the Federation Dentaire Internationale (FDI) system is detailed. Third, tooth surfaces and ridges are explained along with terminology, followed by an explanation of tooth crown and root anatomy. Fourth, the stages of tooth formation are described, starting with the bud stage, and followed by the cap stage, bell stage, and maturation. Annotated diagrams are presented for clarity. Finally, two currently accepted hypotheses explaining tooth formation are presented

Assessment of Knowledge towards Radiation Protection Measures among Newly Graduated Dentists from Egypt and the Kingdom of Saudi Arabia: A Questionnaire-Based Cross-Sectional Study

Background: It is hypothesized that knowledge towards ionizing radiation (IR) protection measures is lacking among newly graduated dentists from Egypt and Saudi Arabia. The purpose of the present questionnaire-based study was to compare the IR protection knowledge among newly graduated dentists from Egypt and the Kingdom of Saudi Arabia (KSA). Methods: The present investigation was a questionnaire-based study and had a cross-sectional observational analytical design. Newly graduated dentists were defined as individuals who had graduated from a credentialed dental institution within the past 36-months. The questionnaire was related to knowledge about radiation safety, awareness and practices. The questionnaire comprised of 17 multiple choice questions. Questionnaires in which all the 17 questions were not answered or had missing pages were excluded. Odds ratios were computed for the number of correct and incorrect responses and 95% confidence intervals were determined. Individuals that provided up to 40%, 41% to 70% and >70% correct answers were categorized as having “low competence”; “moderate competence” and “high competence” in IR knowledge. p-values less than 0.05 were considered statistically significant. Results: The mean percentage of correct answers provided by dentists from Egypt and KSA were 56.9% and 67.4%, respectively. There was no statistically significant difference in the percentages of correct responses for the 17 questions submitted by respondents from Egypt and KSA. The overall percentage of correct responses ranged between 40.2–71.2% and 45.4–81.4% for respondents from Egypt and KSA, respectively. The odds ratios and 95% confidence intervals showed no statistically significant correlation in the responses from respondents from Egypt and KSA for each of the 17 questions addressed. Conclusion: Newly graduated dentists from Egypt and KSA are moderately competent regarding IR doses and related safety measures. It is recommended that modifications in the undergraduate dental education curriculum with emphasis on IR safety and practice would help enhance the knowledge and competence of students and newly graduated dentists. Moreover, routine continuing dental education seminars/programs may help enhance the IR knowledge of dental students and dentists

Periodontal and peri-implant status and whole salivary interleukin 1-beta levels among individuals using selective serotonin reuptake inhibitors: an observational study

Objective: Selective serotonin reuptake inhibitors (SSRI) are commonly used for managing psychological diseases such as depression. These disorders are also directly associated with periodontal and peri-implant diseases, namely periodontitis and peri-implantitis, respectively. It is hypothesized that there is no difference in periodontal and peri-implant clinicoradiographic status and unstimulated whole salivary interleukin (IL)-1β levels in participants using selective serotonin reuptake inhibitors (SSRI) and controls (individuals not using SSRI). The aim of the present observational case-control study was to compare periodontal and peri-implant clinicoradiographic statuses and whole salivary IL-1β in participants using SSRI and controls. Methods: Users of SSRI and controls were included. In all participants, periodontal (plaque index [PI], gingival index [GI], probing depth [PD], clinical attachment loss [AL] and marginal bone loss [MBL]) and peri-implant (modified PI [mPI], modified GI [mGI], PD and crestal bone loss [CBL]) were assessed. Unstimulated whole saliva was collected and IL-1β levels were determined. Information related to duration of implants in function, duration of depressive symptoms and treatment of depression was retrieved from healthcare records. Sample-size was estimated using 5% error and group comparisons were performed. P < 0.05 was considered statistically significant. Results: Thirty-seven SSRI users and 35 controls were assessed. Individuals using SSRI had a history of depression of 4.2 ± 2.5 years. The mean age of SSRI-users and controls were 48.7 ± 5.7 and 45.3 ± 5.1 years, respectively. Tooth brushing twice daily was reported by 75.7% and 62.9% SSRI-users and controls, respectively. There was no statistically significant difference in PI, mPI, GI, mGI, PD, clinical AL, numbers of MT and mesial and distal MBL and CBL among individuals using SSRI compared with controls (Tables 3 and 4). The unstimulated whole salivary flow rate in individuals using SSRI and controls was 0.11 ± 0.003 and 0.12 ± 0.001 ml/min, respectively. Whole salivary IL-1β levels in individuals using SSRI and controls were 57.6 ± 11.6 pg/ml and 34.6 ± 5.2 pg/ml, respectively. Conclusion: Users of SSRI and controls demonstrate healthy periodontal and peri-implant tissue statuses with no marked differences in whole salivary IL-1β levels provided oral hygiene is stringently maintained.Princess Nourah Bint Abdulrahman University - grant No. [PNURSP2022R63, PNURSP2023R63

The antimicrobial activity of tea tree oil (Melaleuca alternifolia) and its metal nanoparticles in oral bacteria

Tea tree (Melaleuca alternifolia) oil (TTO) is an antimicrobial agent, and hence, its use in fabricating nanoparticles (NP) may be useful in providing more efficacious antimicrobial agents. The current research aimed to test the antimicrobial efficacy of TTO and its TTO-Metal-NPs against oral microbes: Porphyromonas gingivalis, Enterococcus faecalis, and Streptococcus mutans. The antimicrobial activity of TTO and zinc (Zn) and iron (Fe) nanoparticles (NPs) and the combined effects of antimicrobial agents were investigated using agar well diffusion assays. Fourier-transform infrared spectroscopy (FT-IR) was used to identify the phyto-constituents of TTO. Field emission scanning electron microscopy (FE-SEM), dynamic light scatter (DLS), and zeta potential were utilized to analyze the biogenic nanoparticles’ morphology, size, and potential. The antimicrobial mode of action was determined by assessing the morphological changes under scanning electron microscopy (SEM). The TTO extracts converted Zn and Fe ions to NPs, having an average size of 97.50 (ZnNPs) and 102.4 nm (FeNPs). All tested agents had significant antibacterial efficacy against the tested oral microbes. However, the TTO extract was more efficacious than the NPs. Combination treatment of TTO with antibiotics resulted in partial additive effects against P. gingivalis and partial antagonistic effects against E. faecalis, S. mutans, and common mouthwashes (Oral B and chlorhexidine). TTO and NP-treated bacteria underwent morphological changes on treatment. M. alternifolia phytochemicals could be useful for further research and development of antimicrobial NPs. The current study highlights the variance in activity observed for different types of bacteria and antagonistic effects seen with common mouthwashes, which represent a threat to therapeutic efficacy and heighten the risk of clinical microbial resistance

Development, In-Vitro Characterization and In-Vivo Osteoinductive Efficacy of a Novel Biomimetically-Precipitated Nanocrystalline Calcium Phosphate With Internally-Incorporated Bone Morphogenetic Protein-2

The repair of large-volume bone defects (LVBDs) remains a great challenge in the fields of orthopedics and maxillofacial surgery. Most clinically available bone-defect-filling materials lack proper degradability and efficient osteoinductivity. In this study, we synthesized a novel biomimetically-precipitated nanocrystalline calcium phosphate (BpNcCaP) with internally incorporated bone morphogenetic protein-2 (BpNcCaP + BMP-2) with an aim to develop properly degradable and highly osteoinductive granules to repair LVBDs. We first characterized the physicochemical properties of the granules with different incorporation amounts of BMP-2 using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. We evaluated the cytotoxicity and cytocompatibility of BpNcCaP by assessing the viability and adhesion of MC3T3-E1 pre-osteoblasts using PrestoBlue assay, Rhodamine-Phalloidin and DAPI staining, respectively. We further assessed the in-vivo osteoinductive efficacy in a subcutaneous bone induction model in rats. In-vitro characterization data showed that the BpNcCaP + BMP-2 granules were comprised of hexagonal hydroxyapatite with an average crystallite size ranging from 19.7 to 25.1 nm and a grain size at 84.13 ± 28.46 nm. The vickers hardness of BpNcCaP was 32.50 ± 3.58 HV 0.025. BpNcCaP showed no obvious cytotoxicity and was favorable for the adhesion of pre-osteoblasts. BMP-2 incorporation rate could be as high as 65.04 ± 6.01%. In-vivo histomorphometric analysis showed that the volume of new bone induced by BpNcCaP exhibited a BMP-2 amount-dependent increasing manner. The BpNcCaP+50 μg BMP-2 exhibited significantly more degradation and fewer foreign body giant cells in comparison with BpNcCaP. These data suggested a promising application potential of BpNcCaP + BMP-2 in repairing LVBDs