Eruption disturbances in the mixed dentition: orthodontic considerations for primary dental care.

The primary dental care clinician is in a prime position to identify deviations from normal dental development. Disturbances can affect any new erupting tooth. The objective of this narrative review is to describe several situations in which eruption disturbances can arise during the mixed dentition. It will provide an overview of the orthodontic considerations of these disturbances in addition to key summary points on interceptive management, based on the best available evidence.

Effectiveness of tongue-tie assessment tools in diagnosing and fulfilling lingual frenectomy criteria: a systematic review.

It is unclear how effective tongue-tie classification assessment tools are in diagnosing symptomatic tongue-tie and fulfilling lingual frenectomy criteria. The purpose of this systematic review is to determine and evaluate any association between tongue-tie severity, as measured by pre-treatment assessment tools, and post-operative outcome following tongue-tie division. PubMed, EMBASE, and the Cochrane search engines were used to retrieve articles published between 1947 and 2021. Included studies consisted of patients with symptomatic tongue-tie, assessment by either the Coryllos, Kotlow, or Hazelbaker Assessment Tool for Lingual Frenulum Function (HATLFF) classification tool, and tongue-tie division. A total of 205 abstracts were identified; 31 studies met the criteria for a full-text review, of which, only 14 studies met the criteria for data extraction and analysis. Six studies used the HATLFF, 2 studies used the Kotlow, 5 studies used the Coryllos, and 1 study used a combination of both Kotlow and Coryllos methods. Significant heterogeneity was evident across all studies. No statistical correlation between the two variables could be determined. Although tongue-tie division procedures appear to provide benefits in breastfeeding and speech, there are no data to suggest a statistically significant association between the severity of tongue-tie, and the correct identification of patients who would benefit from tongue-tie division. © 2022 Australian Dental Association.

The quality and readability of online molar incisor hypomineralization patient education materials: a systematic analysis.

BACKGROUND: Molar incisor hypomineralization (MIH) is estimated to affect 14% of children worldwide. It is crucial that patients and their families have access to easily comprehensible and reliable MIH-relevant information. This study aims to determine the quality, reliability and readability of online patient education materials about MIH. METHODS: A systematic search strategy was adopted. Five validated tools were used to assess the content of the 21 websites that satisfied inclusion/exclusion criteria. Data analyses were applied via GraphPad Prism software version 9 (GraphPad Software, San Diego, CA, USA). RESULTS: Five (23.8%) websites only satisfied the criteria for understandability and two (9.5%) websites satisfied the criteria for actionability using the Patient Education Materials Assessment Tool (PEMAT). No website contained the Health on the Net (HON)Code Seal and the mean (SD) Journal of the American Medical Association number of benchmarks per website was 1.33/4 (1.02). All websites failed to reach recommended minimum readability levels. Higher PEMAT scores were associated with 'easier' readability. CONCLUSIONS: Online patient education materials related to MIH are lacking in quality and reliability, and are too difficult for most to read easily. The authors of MIH-related online content should consider reference to quality of information tools when developing patient education materials.

An assessment of the treatment information contained within the websites of direct-to-consumer orthodontic aligner providers.

BACKGROUND: The use of direct-to-consumer (DTC) orthodontic aligners is growing. The purpose of this study was to evaluate the quality of information contained within the websites of DTC orthodontic aligner providers. METHODS: Websites that satisfied inclusion criteria were assessed for the presence of specific treatment-related features. Four validated quality of information instruments and readability tools were used to evaluate the content of the websites. Descriptive statistical analyses and intra-examiner reliability tests were performed. RESULTS: Twenty-one websites were evaluated. Few websites referred to the need for pre-treatment dental health (38.1%) and indefinite post-treatment retention (23.8%). Most websites (95.2%) were categorized as either 'poor' or 'very poor' according to their DISCERN scores. DISCERN items regarding information bias and treatment risks scored particularly poorly. Cohen's kappa intra-examiner reliability testing for DISCERN scores was 0.81-0.89. Three websites honoured two out of the four Journal of the American Medical Association benchmarks and 18 honoured one benchmark only. The readability scores indicated 'difficult to read' content. CONCLUSIONS: The quality of information contained within the websites of DTC orthodontic aligner providers is poor. Patient consent for DTC aligner treatment based solely on the information contained within the websites is likely to be invalid.

Web-based information on orthodontic clear aligners: a qualitative and readability assessment.

BACKGROUND: Data regarding the quality of information (QOI) related to orthodontic clear aligners (OCAs) on the internet are lacking. The aim of the present investigation was to assess the quality and readability of websites providing information regarding OCAs to prospective patients. METHODS: Three search terms were entered separately into three search engines. Four validated QOI instruments were used to determine the QOI and readability of the content contained within the websites that satisfied predetermined criteria. Descriptive statistical analyses and intrarater testing for DISCERN scores were calculated. RESULTS: Forty-nine websites satisfied inclusion/exclusion criteria. General dentists (44.9%) and specialist orthodontists (26.5%) authored the majority of websites. One website contained the Health on the Net (HON) code seal. Cohen's kappa for DISCERN scores was good (0.87). The overall mean (SD) DISCERN score was 38.55 (8.00)/80, range 26-60. The websites authored by 'Direct-to-consumer' OCA providers recorded the lowest DISCERN mean score (33/80). One website contained all four Journal of the American Medical Association (JAMA) benchmarks. The mean (SD) Flesch Reading Ease score was 53.92 (9.08), range 36-82.5. CONCLUSIONS: The QOI of the website content related to OCAs is poor and is 'fairly difficult' to read. Website authors should consider using QOI instruments and readability tools to enable the delivery of evidence-based and easily readable information regarding OCAs to prospective patients.

Ultrasound measurements of the masseter muscle as predictors of cephalometric indices in orthodontics: a pilot study.

This study investigated the potential of ultrasound measurements of the masseter muscle to accurately predict indices normally derived from cephalograms. Masseter muscle measurements on 11 adults (22 to 30 y) were made using lateral cephalometrics and extended field-of-view ultrasound. The ultrasound technique was validated in a simulation pilot study using 12 dry skulls and raw chicken breasts. Twenty cephalometric variables were analyzed against four ultrasound measurements of the masseter muscle. Highly significant correlations (r = 0.81-0.85, p = 0.001-0.002) between ultrasound measurements of the masseter muscle and cephalometric measurements representing the length of the superficial masseter muscle, the length and shape of the mandible and vertical facial proportions were demonstrated. Predictive equations from regression analyses were constructed to deduce ramus length and shape from the ultrasound measurements. The results provide pilot data suggesting that ultrasound is a potential clinical tool for sequential evaluation of masseter muscle length in orthodontics and facial muscle growth studies.

The localisation of ED1 antibody in the resorbing hard tissues of the periodontium.

A dental hard tissue resorptive model was used to determine the periodontal ligament (PDL) distribution of lysosomal membrane antibody ED1 to cells of the macrophage-phagocyte lineage. Immunolabel was identified in mononuclear cells around inflammatory sites in the PDL, while multinuclear cells were labelled in resorption bays present in both bone and dentine. As repair of the tissues occurred, the label became less obvious. The presence of strong ED1 label in alveolar bone marrow provided evidence supporting the haemopoietic origin of the similarly labelled PDL cells. Also, evidence confirming the current theory that multinucleated resorptive cells differentiate along a monocyte-macrophage pathway was provided. t was concluded that ED1 is a positive PDL marker for mononuclear and multinuclear cells involved in the inflammatory and resorptive processes.

Hypothermic insult to the periodontium: a model for the study of aseptic tooth resorption.

The aim of the current investigation was to define an animal model for the study of hard tissue resorption by examining the responses of the periodontal ligament (PDL) to both single and multiple episodes of hypothermic injury to the crowns of rat teeth. A group of 12 male rats weighing 200-250 g were anesthetized, and pellets of dry ice (CO2) were applied once to the crowns of the right first maxillary molars for continuous periods of 10 or 20 min. Animals were sacrificed at 2, 7, 14 and 28 days and tissues were processed for routine histological examination. A second group of eight animals and a third group of 12 animals were subjected to three applications of dry ice over a period of 1 week and sacrificed at 2 and 14 days respectively after the final application. In addition to thermal insult, the periodontium of teeth from a fourth group of six rats was subjected to mechanical trauma. Examination of the sections from the group undergoing a single freezing episode revealed that, by 1 week, shallow resorption lacunae had appeared on the root surface. These became more extensive after 14 days. At the same time hyaline degeneration was evident in the PDL. Within this group, teeth subjected to the longer 20-min application times generally showed more extensive injuries. By 28 days, evidence of repair was observed with reparative cementum beginning to line the resorption lacunae in the root dentin. Sections from animals subjected to multiple episodes of thermal trauma and those subjected to additional mechanical insult showed more extensive external root resorption than those from single-injury animals. It was concluded that low temperature stimuli applied to the crowns of rat molars were capable of eliciting a sterile degenerative response in the PDL which, in turn, resulted in external root resorption. Furthermore, the degree of this tissue injury was commensurate with the duration and number of exposures to the trauma. The results also indicated that progression of the resorptive process required periodic exposure to the injury, in the absence of which repair to the damaged root occurred.

Begg appliance management of a moderately crowded Angle Class 11 Division 2 malocclusion.

A case is presented that shows Begg appliance management of an Angle Class II division 2 malocclusion. The judicious use of anchorage bends and Class II elastics enabled the successful treatment of the poor posterior and anterior relationships, at the same time addressing the chief complaint of crooked front teeth.

Microvascular luminal volume changes in aged mouse periodontal ligament.

Data for the microvascular bed in the aged periodontal ligament have not been established. This investigation tested the hypothesis that the luminal microvascular volume decreased in the aged ligament. Mice 35 days old and one year old were vascular-perfused and the mandibular first molar periodontal ligament processed for electron microscopy. Tissue quadrats from each circumferential third ligament region were recorded at 150-microns intervals from the alveolar crest to the apex for randomized sampling of blood vessel lumina. The data were analyzed with a generalized linear model at the p < 0.01 level for the interaction of the aging effect with differences across regions. Stereological parameters were established for vessel lumen volume, and for surface and length densities. Mean ligament width decreased from 119.9 +/- 16.94 (micron +/- SE) in young mice to 60.0 +/- 10.58 (micron +/- SE) in aged mice. The luminal volume of 8.63 +/- 1.37 (% +/- SE) in young ligament increased to 9.83 +/- 2.14 (% +/- SE) in aged ligament. Collecting venules and the combined group of arterio-venous anastomoses with terminal arterioles showed a two-fold increase in luminal volume density (p < 0.01). In aged ligament, regional shifts affected the microvascular bed distribution, but these changes were not consistent across regions, or with depth. The average cross-sectional tissue area served per capillary decreased from 2117 microns 2 to 1451 microns 2 for young and old. Average ligament thickness served per capillary dropped from 52.5 microns to 27.5 microns. These reductions in average diffusion distances indicated a change in the quality of the diffusion barrier with age.

An evaluation of the J.O.E. cephalometric software.

JOE is a computerised cephalometric programme produced and promoted by Rocky Mountain Orthodontics. It is simple to use and prints a static cephalometric case description for diagnostic purposes. Although not greatly endowed with features, it provides a relatively painless and cost effective introduction to computerised cephalometrics.

Evidence for endothelial junctions acting as a fluid flux pathway in tensioned periodontal ligament.

A continuous tension load of 1.0 N applied to the rat maxillary first molar for 30 min led to a significant increase (p < 0.05) in the mean number of junctions/microns of endothelial perimeter. The mean number of junctions/microns was compared with the mean number of tissue channels/microns 2 as previously reported by fitting linear and quadratic equations. An increase in the mean number of junctions/microns was associated with an increase in mean number of tissue channels/microns 2 (p < 0.01) in control and experimental periodontal ligament. Significant increases in the mean number of junctions/microns occurred in the middle-third zone for venous capillaries (p < 0.01) and in the tooth-third zone for postcapillary-sized venules (p < 0.001). It is concluded that the endothelial junctions of venous capillaries and postcapillary-sized venules provide significant pathways for fluid transport across the tensioned walls of the microvascular bed of the periodontal ligament.

A scanning electron microscope study of microcorrosion casts of the microvasculature of the marmoset palate, gingiva and periodontal ligament.

In the hard palate, sagittally oriented capillary loops, 8-10 microns in diameter and 70-250 microns high, extended perpendicularly from a subcapillary plexus to the connective tissue papillae. These loops formed a well-delineated vascular spine beneath the rugal crests. Capillary loop density was estimated to be 200-270/mm2 on the rugal crest, 75-160/mm2 on the rugal slopes and 70-140/mm2 in the trough. In the gingiva, the crevicular loop system was separated by a gap from the vestibular, palatal and col loop systems. Anastomoses occurred between these systems at a deeper level. The crevicular circular plexus varied from 1 to 4 vessels. Apical to the gingival margin the buccal vasculature was composed of occluso-apically orientated loops draining towards the vestibular sulcus. The capillary loops were 60-120 microns high near the gingival margin, compared with 40-60 microns near the mucogingival junction. The mucogingival margin was demarcated by a change in capillary orientation. The periodontal ligament contained mainly postcapillary-sized venules, 10-25 microns in diameter, orientated occluso-apically. Capillary loops, 50-100 microns long and directed at right angles to the root surface, occurred in the cervical third. These microvascular patterns of the marmoset are different from those of the mouse and rat.

Stereo-pair three-dimensional imaging of microvascular architecture in primate dental tissues.

The morphology of microvascular beds in dental tissues is poorly documented at the ultrastructural level. SEM stereo-pair imaging of microcorrosion casts reveals the markedly contrasting vascular architecture and capillary anastomoses within the nasopalatine foramen, soft palate and gingival regions of the marmoset. This primate was studied as an analogue for man to further our knowledge of periodontal anatomy and function.

A morphometric, electron microscopic analysis of tissue channels shown by ionic tracer in normal and tensioned rat molar apical periodontal ligament.

A 1.0 newton continuous, extrusive load was applied to the right maxillary molar for 30 min to determine the presence of channels as shown by the distribution of tracer across the interstitial compartment of normal and tensioned PDL. Sodium ferrocyanide (1% w/v), perfused via the common carotid arteries, was the tracer probe and tris(ethylenediamine) cobalt III chloride (1% w/v) the precipitating ion. Left molar control PDL had an overall mean of 0.43 +/- 0.05/microns2 tissue channels at 0.2 microns from the vascular endothelium, and 0.15 +/- 0.04/microns2 at 7-8 microns. On the experimental side, the overall mean number of tissue channels was 0.65 +/- 0.13/microns2 at 0-2 microns and 0.19 +/- 0.07/microns2 at 7-8 microns. A significant depth effect (P less than 0.01) was present in the control and experimental interstitial tissues for tissue channels adjacent to the endothelium of different categories of vessel. Extrusion increased the tissue channel density adjacent to arterial capillaries (P less than 0.01), venous capillaries (P less than 0.01) and postcapillary-sized venules (P less than 0.01). These findings implicate these three types of vessel as being functionally important in fluid exchange across endothelial boundaries in the PDL.