Comparing the accuracy of 3 different liquid crystal display printers for dental model printing.

INTRODUCTION: This study aimed to evaluate the accuracy in terms of trueness and precision of 3 different liquid crystal display (LCD) printers with different cost levels. METHODS: Three LCD 3-dimensional (3D) printers were categorized into tiers 1-3 on the basis of cost level. The printers' accuracies were assessed in terms of trueness and precision. For this research, 10 standard tessellation language (STL) reference files were used. For trueness, each STL file was printed once with each 3D printer. For precision, 1 randomly chosen STL file was printed 10 times with each 3D printer. After that, a model scanner was used to scan the models, and STL comparisons were performed using reverse engineering software. For the measurements regarding trueness and precision, the Friedman test was used. RESULTS: There were significant differences among the 3 printers (P <0.05). The trueness and precision error were lower in models printed with a tier-1 printer than in the remaining 3D printers (P <0.05). The tier-2 and -3 printers presented very similar performance. CONCLUSIONS: LCD 3D printers can be accurately used in orthodontics for model printing depending on the specific orthodontic use. The cost of a printer is relevant to the results only for the higher expense of the 3D printer in this study.

Comparing CBCT to model scanner for dental model scanning. An in vitro imaging accuracy study.

OBJECTIVE: The aim of this study is to compare the accuracy of cone beam computed tomography (CBCT) for dental model scanning to the accuracy of model scanners. METHODS: Subjects from private practice were collected and scanned according to specific selection criteria. A total of 10 STL files were produced and used as reference files. They were printed with a three-dimensional (3D) printer and then scanned with CBCT and model scanner. For trueness evaluation, all models were scanned once with both equipments. Each file derived from each scan was compared with the corresponding reference model file. For the precision measurements, the physical model from the first master reference model file was scanned 10 times with each equipment and compared with the reference STL file. A reverse engineering software was used for all 3D best-fit comparisons. RESULTS: With regard to the measurement of trueness of each method, the calculated mean root mean square (RMS) value was 0.06±0.01mm for the CBCT, and 0.15±0.02mm for the model scanner. There was a significant difference between the two methods (P<0.01). For the evaluation of precision of each scanner, the mean RMS value was 0.0056±0.001mm for the CBCT, and 0.153±0.002mm for model scanner. There was a significant difference between the two methods (P<0.01). CONCLUSIONS: Cone Beam Computed Tomography seems to be an accurate method for scanning dental models. CBCT performs better than model scanners to scan dental models in terms of trueness and precision.

Molecular and Biological Aspects of Orthodontic Tooth Movement: Possibilities for Bioengineering Intervention: A Narrative Review.

BACKGROUND: The current review's goal is to examine, with a critical eye, the effect of various biomedical parameters on orthodontic tooth movement in an attempt to provide the reader with related mechanisms of this issue focusing on certain key points. METHODS: This critical review was conducted using the following keywords in the search strategy: "biomedical molecules", "biomarkers", "orthodontics", "orthodontic tooth movement", "acceleration", "gene therapy", and "stem cells". Cochrane Library, Medline (PubMed), and Scopus were the databases that were used for the electronic search. Studies published until June 2023 were considered. RESULTS: The use of biomedical approaches in orthodontic tooth movement has been investigated via different procedures and applications. Surgical approaches, biomarkers affecting orthodontic tooth movement, different biological events and mechanisms, RANK, RANK-L, OPG molecular triad, and vibration methods are the basic parameters of biomedical interventions that are examined in the present review. CONCLUSIONS: The biomedical approach seems to offer a variety of applications to control orthodontic tooth movement. The scarcity of human studies, as well as the high cost and complexity of these methods, currently limit the available accurate data concerning this issue.

Effects of Diet Consistency on Rat Maxillary and Mandibular Growth within Three Generations-A Longitudinal CBCT Study.

BACKGROUND: In this study, wistar rats were used to examine the impact of diet consistency on maxillary and mandibular growth over three generations. METHODS: In this investigation, a breeding sample of 60 female and 8 male wistar rats was used. Measuring was only performed on female animals. The first generation's primary breeding sample consisted of 20 female wistar rats that were 30 days old and 4 male rats that were also 30 days old; two subsequent generations were created from these animals. At the age of 100 days, CBCTs were collected of all male rats. Twenty-eight craniofacial landmarks were selected for the linear measurements on stl format extracted from the DICOM files. A Bonferroni test was performed for the statistical analysis. RESULTS: Means of measurements of all soft diet groups compared to corresponding measurements of the hard diet groups were significantly different. According to linear measurements, there was statistical difference on the maxillary measurements between the soft diet groups of the first and third generation, while the rest did not appear to have any statistical difference. There was significant difference for the mandibular dimensions only when the first generation soft diet group was compared with the third generation soft diet group. CONCLUSIONS: Food consistency has a significant impact on the growth and development of the maxilla and mandible. Soft diet habits may result in retrognathic mandible, and narrower maxilla.

The Effect of Third Molars on the Mandibular Anterior Crowding Relapse-A Systematic Review.

The present systematic review updates the evidence on wisdom teeth contributing to lower incisor crowding following orthodontic treatment. Relevant literature was searched on online databases, namely Pubmed, Scopus, and Web of Science, up to December 2022. Eligibility criteria were formulated using the PICOS approach and PRISMA guidelines. Eligible research included original clinical studies involving patients previously being treated orthodontically with permanent dentition at the end of treatment, regardless of sex or age. The initial search yielded 605 citations. After considering eligibility criteria and removing duplicates, only 10 articles met the criteria for inclusion. The risk of bias of eligible studies was evaluated using the Cochrane Handbook for Systematic Reviews and Interventions tool. The majority were highly biased, mainly regarding allocation concealment, group similarity, and assessment blinding. The vast majority did not report statistically significant associations between the presence of third molars and crowding relapse. However, a minor effect has been suggested. Seemingly, there is no clear connection between mandibular third molars and incisor crowding after orthodontic treatment. The present review did not find adequate evidence to advocate preventative removal of the third molars for reasons of occlusal stability.

Direct 3D-Printed Orthodontic Retainers. A Systematic Review.

Three-dimensional (3D) printing technology has shed light on many fields in medicine and dentistry, including orthodontics. Direct 3D-printed prosthetics, implants or surgical devices are well-documented. The fabrication of orthodontic retainers using CAD technology and additive manufacturing is an emerging trend but the available data are scarce. The research approach of the present review included keywords in Medline, Scopus, Cochrane Library and Google Scholar up to December 2022. The searching process concluded with five studies eligible for our project. Three of them investigated directly 3D-printed clear retainers in vitro. The other two studies investigated directly 3D-printed fixed retainers. Among them, one study was in vitro and the second was a prospective clinical trial. Directly 3D-printed retainers can be evolved over time as a good alternative to all the conventional materials for retention. Devices that are 3D-printed are more time and cost efficient, offer more comfortable procedures for both practitioners and patients and the materials used in additive manufacturing can solve aesthetic problems, periodontal issues or problems with the interference of these materials with magnetic resonance imaging (MRI). More well-designed prospective clinical trials are necessary for more evaluable results.

Effects on Facial Growth Following Masseter Muscle Resection in Growing Rats-A Systematic Review.

An individual's facial appearance is heavily influenced by facial symmetry. In the asymmetric mandible, periosteal apposition and endochondral ossification in one of the condyles may stimulate asymmetric growth of the body. Our aim was to review the impact on the growth following masseter resection. Relevant studies up to October 2022 were retrieved from PubMed, Scopus, and Web of Science. The PICOS method was utilized to determine eligibility, and the SYRCLE risk of bias tool was utilized to provide an estimate of potential bias. A predetermined algorithm was used to search the databases. The results of our systematic review of seven studies indicate that the masseter muscle strongly impacts craniofacial growth and development. Resection of the masseter muscle significantly reduces the sagittal and vertical development of the jaw in rats. In addition, the masseter muscle excision influences the mandibular morphology, including the condylar area, angle, and development direction of the jaw.

Long-Term Effect of Diet Consistency on Mandibular Growth within Three Generations: A Longitudinal Cephalometric Study in Rats.

BACKGROUND: This study investigated the effect of diet consistency on mandibular growth of Wistar rats through three generations. METHODS: A total breeding sample of 60 female and 8 male Wistar rats were used in this study. Measurements took place only on female animals. Twenty female Wistar rats at 30 days old and four male rats at 30 days old comprised the primary breeding sample of the first generation, and from these animals two different generations were reproduced. Lateral cephalometric X-rays were taken from all female rats at the age of 100 days. A total of 7 craniofacial landmarks were selected for the linear measurements, and 12 curves and 90 landmarks were selected for geometric morphometric analysis of the lateral X-rays. Bonferroni test and a permutation test were performed for the statistical analysis. RESULTS: Means of measurements of all soft diet groups compared to hard diet groups were significantly smaller. According to linear measurements, there was a significant difference only between the first-generation soft diet with the third-generation soft diet group. According to geometric morphometric analysis, the statistical differences appeared on the condylar process and the angle of the mandible. CONCLUSIONS: The soft diet could be responsible for less mandibular growth, and this information might be passing through generations.

Full Mouth Treatment of Early Childhood Caries with Zirconia Dental Crowns: A Case Report.

Pediatric dentists should always strive for cosmetic and functional rehabilitation when treating decaying or injured primary teeth. The most popular restoration technique for such teeth is "strip crowns" made of composite materials, but more recently, zirconia and preveneered stainless steel crowns have gained popularity. Moreover, zirconia crowns are usually preferred over stainless steel crowns for aesthetic reasons. The aim of this case report is to present a 4-year-old patient with a high caries risk who underwent a full-mouth pediatric zirconia crown treatment. The operation was performed under general anesthesia. This article describes the restoration of all primary teeth and the follow-up 6 months after the parents' request to improve the aesthetics. The gingival health and the adaptation of the zirconia crown were evaluated both clinically and radiologically. In this case, the preformed pediatric zirconia crowns provided functional and durable restoration while restoring the natural appearance of the teeth. However, primary dental prevention, including education on oral hygiene and dietary habits, remains the cornerstone in preventing early childhood caries and promoting oral health in pediatric patients. It is important to note that dental intervention under general anesthesia should only be considered as a last resort after all other options have been exhausted, due to the potential risks associated with the use of general anesthesia.

Orthodontic Retainers-A Critical Review.

The achievement of aesthetic, functional occlusion should not mark the end of the orthodontic intervention. To prevent relapse, retention needs advance planning, and may vary in duration. This review aims to present and comment on the available means of retention. The ever-popular, passive Hawley-like removable appliances are credible in maintaining the desired occlusion. Modifications are the removable appliance Wrap Around, having the labial archwire extending to the premolars; the translucent retainer, Astics, a unique aesthetic Hawley-type device; and the reinforced removable retainer, which features a metallic grid reinforcing the acrylic base. Vacuum-formed retainers are easy to fabricate and are readily prescribed. By contrast, fixed retainers are made of orthodontic wire and composite resin bonded on the lingual or palatal surfaces of the anterior teeth. Patient-related variables need evaluation to select the appropriate retainer, while patients ought to realize the importance of retention and comply with offered guidance. Overall, the orthodontist is responsible for keeping the patient informed on the properties and the duration of retention, even before starting active orthodontic treatment.

Comparison between orthodontic and surgical uprighting of mandibular molars: a systematic review.

OBJECTIVES: To evaluate and compare the efficiency of orthodontic treatment and surgical uprighting of first and second mandibular molars. MATERIALS AND METHODS: An electronic literature search in PubMed, Science Direct, Embase, Scopus, Web of Science, Cochrane Library, LILACS, and Google Scholar, as well as a hand search was conducted by two independent researchers to identify relevant articles up to January 2022. In addition, a manual search was done that included article reference lists, grey literature, and dissertations. The risk of bias of the included prospective and retrospective studies was assessed with the Risk Of Bias Tool In Non-randomized Studies of Interventions (ROBINS-I) assessment tool. RESULTS: A total of six nonrandomized clinical trials (non-RCT) evaluating the efficiency of mandibular molar orthodontic and/or surgical uprighting were included. The quality analysis showed certain defects of the Non-RCTs included and, according to the criteria used, the majority of the articles were judged to be of moderate quality. CONCLUSIONS: Based on the evidence, orthodontic and surgical uprighting appear to be effective treatment methods for mandibular molars. Surgical uprighting may be associated with more complications than orthodontic uprighting. However, the existing literature on the subject is limited, heterogeneous, and methodologically limited. Therefore, the outcomes should be interpreted carefully.

Frequency and Management of Accidental Incidents in Orthodontics.

BACKGROUND: The present study aims to define through questionnaires the frequency and the variety of accidental incidents occurring in orthodontic clinical practice among Greek practicing orthodontists. METHODS: A questionnaire survey was conducted among orthodontists from the registry of orthodontists in Greece. The questionnaire was divided into two parts. The first part involved three questions relating to the socio-demographic status and the background of the orthodontist, and the second part concerned exclusively the frequency of accidental incidents that have occurred during clinical practice with three possible answers: never, once, more than once. RESULTS: From the 200 initially distributed questionnaires, 124 were finally completed and sent back (response rate: 62%). The results showed that orthodontists with more years of clinical practice had faced more accidental incidents. Among the ingestion incidents caused by foreign objects, the most frequently occurring was the ingestion of elastic separators, followed by the ingestion of elastic ligatures and ingestion of hooks. The most commonly reported traumatic incidents were the trauma-lesion of the mucosa by the orthodontic wire or part of it, followed by trauma-lesion by hooks and wire ligatures. The reported number of incidents with further complications and with patients referred to an emergency room was very low. CONCLUSIONS: The results of the present study determined a high frequency of accidental incidents among Greek orthodontists. The longer clinical experience was accompanied by more accidental incidents. Orthodontists, like other health professionals, must learn and continuously update their knowledge regarding the management protocols of medical emergencies.

Dental and Skeletal Effects of Herbst Appliance, Forsus Fatigue Resistance Device, and Class II Elastics-A Systematic Review and Meta-Analysis.

Background: Our study aimed to systematically summarize the dentoskeletal effects of Herbst appliance; Forsus fatigue resistance device; and Class II elastics in adolescent Class II malocclusion. Methods: Five databases; unpublished literature; and reference lists were last searched in August 2022. Randomized clinical trials and observational studies of at least 10 Class II growing patients that assessed dentoskeletal effects through cephalometric/CBCT superimpositions were eligible. The included studies quality was assessed with the RoB 2 and ROBINS-I tools. A random-effects model meta-analysis was performed. Heterogeneity was explored with subgroup and sensitivity analyses. Results: Among nine studies (298 patients); two-to-three studies were included in each meta-analysis. Less post-treatment upper incisor retroclination (<2) and no overbite; overjet; SNA; SNB; and lower incisor inclination differences were found between Herbst/Forsus and Class II elastics. No differences in maxilla; condyle; glenoid fossa; and most mandibular changes were found between Herbst and Class II elastics; except for a greater 1.5 mm increase in mandibular length and right mandibular ramus height (1.6 mm) with Herbst. Conclusions: Herbst and Class II elastics corrected the molar relationship; but Herbst moved the lower molars more mesially. Apart from an additional mandibular length increase; no other dental and anteroposterior skeletal difference was found. Forsus was more effective in molar correction; overjet reduction; and upper incisor control than Class II elastics. Trial registration number OSF: 10.17605/OSF.IO/8TK3R.

Artificial Intelligence as an Aid in CBCT Airway Analysis: A Systematic Review.

BACKGROUND: The use of artificial intelligence (AI) in health sciences is becoming increasingly popular among doctors nowadays. This study evaluated the literature regarding the use of AI for CBCT airway analysis. To our knowledge, this is the first systematic review that examines the performance of artificial intelligence in CBCT airway analysis. METHODS: Electronic databases and the reference lists of the relevant research papers were searched for published and unpublished literature. Study selection, data extraction, and risk of bias evaluation were all carried out independently and twice. Finally, five articles were chosen. RESULTS: The results suggested a high correlation between the automatic and manual airway measurements indicating that the airway measurements may be automatically and accurately calculated from CBCT images. CONCLUSIONS: According to the present literature, automatic airway segmentation can be used for clinical purposes. The main key findings of this systematic review are that the automatic airway segmentation is accurate in the measurement of the airway and, at the same time, appears to be fast and easy to use. However, the present literature is really limited, and more studies in the future providing high-quality evidence are needed.

Comparing a Fully Automated Cephalometric Tracing Method to a Manual Tracing Method for Orthodontic Diagnosis.

Background: This study aims to compare an automated cephalometric analysis based on the latest deep learning method of automatically identifying cephalometric landmarks with a manual tracing method using broadly accepted cephalometric software. Methods: A total of 100 cephalometric X-rays taken using a CS8100SC cephalostat were collected from a private practice. The X-rays were taken in maximum image size (18 × 24 cm lateral image). All cephalometric X-rays were first manually traced using the Dolphin 3D Imaging program version 11.0 and then automatically, using the Artificial Intelligence CS imaging V8 software. The American Board of Orthodontics analysis and the European Board of Orthodontics analysis were used for the cephalometric measurements. This resulted in the identification of 16 cephalometric landmarks, used for 16 angular and 2 linear measurements. Results: All measurements showed great reproducibility with high intra-class reliability (>0.97). The two methods showed great agreement, with an ICC range of 0.70−0.92. Mean values of SNA, SNB, ANB, SN-MP, U1-SN, L1-NB, SNPg, ANPg, SN/ANS-PNS, SN/GoGn, U1/ANS-PNS, L1-APg, U1-NA, and L1-GoGn landmarks had no significant differences between the two methods (p > 0.0027), while the mean values of FMA, L1-MP, ANS-PNS/GoGn, and U1-L1 were statistically significantly different (p < 0.0027). Conclusions: The automatic cephalometric tracing method using CS imaging V8 software is reliable and accurate for all cephalometric measurements.

Applications of Biotechnology to the Craniofacial Complex: A Critical Review.

BACKGROUND: Biotechnology shows a promising future in bridging the gap between biomedical basic sciences and clinical craniofacial practice. The purpose of the present review is to investigate the applications of biotechnology in the craniofacial complex. METHODS: This critical review was conducted by using the following keywords in the search strategy: "biotechnology", "bioengineering", "craniofacial", "stem cells", "scaffolds", "biomarkers", and "tissue regeneration". The databases used for the electronic search were the Cochrane Library, Medline (PubMed), and Scopus. The search was conducted for studies published before June 2022. RESULTS: The applications of biotechnology are numerous and provide clinicians with the great benefit of understanding the etiology of dentofacial deformities, as well as treating the defected areas. Research has been focused on craniofacial tissue regeneration with the use of stem cells and scaffolds, as well as in bioinformatics with the investigation of growth factors and biomarkers capable of providing evidence for craniofacial growth and development. This review presents the biotechnological opportunities in the fields related to the craniofacial complex and attempts to answer a series of questions that may be of interest to the reader. CONCLUSIONS: Biotechnology seems to offer a bright future ahead, improving and modernizing the clinical management of cranio-dento-facial diseases. Extensive research is needed as human studies on this subject are few and have controversial results.

Histological and Biochemical Analysis after Posterior Mandibular Displacement in Rats.

The present study aimed to investigate any biochemical and histological changes of the rat condyle and mandible in animals that had sustained mandibular growth restriction. Seventy-two male Wistar rats were divided into two equal groups, experimental and control. Each group consisted of three equal subgroups. The animals were sacrificed 30, 60, and 90 days after the start of the experiment. Blood samples were collected from the eye, and the osteoprotegerin (OPG), Receptor Activator of Nuclear Factor Kappa B Ligand (RANKL), and Macrophage Colony-Stimulating factor (MCSF)concentrations were measured by using enzyme-linked immunosorbent assay (ELISA) kits. A histological analysis was performed on the mandibular condyles. The blood serum values of OPG, RANKL, and MCSF did not exhibit any statistically significant difference between groups or subgroups. However, significant histological changes became evident after a histomorphometric condylar examination was performed. The Bone Surface/Total Surface ratio appeared reduced in the anterior and posterior regions of the condyle. In addition, the Posterior Condylar Cartilage Thickness was measured and determined to be significantly diminished. The present intervention that employed orthodontic/orthopedic devices did not prove to have any significant effect on the circulating proteins under study. Posterior displacement of the mandible may culminate only in local histological alterations in condylar cartilage thickness and its osseous microarchitecture.

Comparison in Terms of Accuracy between DLP and LCD Printing Technology for Dental Model Printing.

BACKGROUND: The aim of this study is to evaluate the accuracy of a Liquid Crystal Display (LCD) 3D printer compared to a Direct Light Processing (DLP) 3D printer for dental model printing. METHODS: Two different printers in terms of 3D printing technology were used in this study. One was a DLP 3D printer and one an LCD 3D printer. The accuracy of the printers was evaluated in terms of trueness and precision. Ten STL reference files were used for this study. For trueness, each STL file was printed once with each 3D printer. For precision, one randomly chosen STL file was printed 10 times with each 3D printer. Afterward, the models were scanned with a model scanner, and reverse engineering software was used for the STL comparisons. RESULTS: In terms of trueness, the comparison between the LCD 3D printer and DLP 3D printer was statistically significant, with a p-value = 0.004. For precision, the comparison between the LCD 3D printer and the DLP 3D printer was statistically significant, with a p-value = 0.011. CONCLUSIONS: The DLP 3D printer is more accurate in terms of dental model printing than the LCD 3D printer. However, both DLP and LCD printers can accurately be used to print dental models for the fabrication of orthodontic appliances.

Anterior Mandibular Displacement in Growing Rats-A Systematic Review.

Skeletal Class II malocclusion is the most common skeletal anomaly in orthodontics. Growth in the body of the deficient mandible is induced by periosteal apposition and endochondral ossification in the condyle. Functional appliances have been used in the correction of Class II malocclusions by inducing mandibular growth. Despite their utilization though, their effect still remains controversial. The aim of the present study is to review the existing literature regarding the effects of mandibular protrusion in mandibular growth of growing rats. A protocol was followed according to the guidelines of the Cohrane Handbook for Systematic Reviews. Databases were searched using a specific algorithm. From the ten studies finally analyzed, we conclude that the use of a functional appliance in growing rats induces cell proliferation and bone formation in their condyles, resulting in mandibular growth.

Frequency and Local Etiological Factors of Impaction of Permanent Teeth among 1400 Patients in a Greek Population.

BACKGROUND: The purpose of this study is to analyze the frequency of impaction of permanent teeth, beyond the third molars, and to highlight the factors causing this condition. METHODS: Panoramic radiographs of 1400 patients that sought orthodontic treatment in private practice were retrieved and examined. All teeth that had not been erupted at the time of the examination while their root formation was completed were considered impacted. RESULTS: In total, 212 out of 1400 patients had at least one impacted tooth (15.14%). The highest incidence of tooth impaction was in the canines of the maxilla, followed by the central incisors of the maxilla, the second molars of the mandible and the second premolars of the mandible. The most common etiological factors responsible for the impaction were the ectopic eruption pathway, loss of space in the arch, the ankylosis of the deciduous teeth and the presence of supernumerary teeth. CONCLUSIONS: Tooth impaction is frequently seen in everyday orthodontic practice. The upper canines are the teeth most frequently associated with impaction and failure of eruption. It is important to diagnose cases of impaction early on and identify the etiological factors in order to achieve immediate and effective treatment per patient.