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.

Alveolar bone response distal to applied orthodontic forces in ovariectomized rats.

OBJECTIVES: The aim of this study was to investigate the effect of the application of orthodontic tooth forces on the alveolar bone distal to the loaded teeth, in ovariectomized female rats. METHODS: Twenty-four eight-month-old Wistar rats were divided into one group ovariectomized at the age of six months and one control. An orthodontic appliance delivering a mesial traction force of 60 gr* was placed on the right maxillary 1st molar of all animals for 14 days. Histology of the alveolar bone, of the adjacent and distal teeth to the loaded molar and the contralateral side, was performed following euthanasia. RESULTS: In the non-ovariectomized rats, extensive resorption was noticed in the direction of the orthodontic movement in the 2nd and 3rd molar interdental space, whereas the respective contralateral interdental space did not show any remodeling activity. Ovariectomized rats displayed reduced osseous tissue in the interdental space of both sides. The alveolar bone in the interradicular area of the 2nd loaded molar revealed frontal resorption, whereas, the alveolar interradicular bone of the contralateral 2nd molar showed internal resorption. CONCLUSIONS: In conclusion, orthodontic forces applied to the dentoalveolar complex of ovariectomized rats affect bone remodeling, even in areas distal to the site of force application. This finding should be taken into account during orthodontic treatment of women during menopause.

Intrauterine growth restriction affects bone mineral density of the mandible and the condyle in growing rats.

OBJECTIVES: To investigate in growing rats the effect of intrauterine growth restriction (IUGR) on the bone mineral density of the mandible and tibia, as well as the quality of the mandibular and condylar bone. METHODS: Twelve male rats were born IUGR by mothers sustaining 50% food restriction during pregnancy. Twelve control male rats were born by mothers fed ad libitum. Dual-energy X-ray absorptiometry (DEXA) of the tibia, proximal tibial metaphysis and the mandible, biochemical markers, histology and histomorphometrical analysis on the mandibular and subchondral bone of the condyle were performed. RESULTS: IUGR significantly affected bone mineral density (BMD) of both tibial and mandibular bones. IUGR rats had significantly lower osteocalcin values (p=0.021) and phosphorus (p=0.028), but not 25-OH vitamin D (p=0.352). Bone area percentage in the mandible was significantly lower (51.21±5.54) in IUGR compared to controls (66.00±15.49), and for subchondral bone of the condyle for IUGR (47.01±6.82) compared to controls (68.27±13.37). IUGR had a significant reduction in the fibrous layer, but not the proliferating layer, with the hypertrophic layer significantly increased. CONCLUSION: Maternal restricted nutrition during gestation can affect BMD of the mandible and the tibia of the offspring animals.

Patient-reported experiences and preferences with intraoral scanners: a systematic review.

BACKGROUND: Intraoral scanners have become an increasingly popular alternative to conventional impression methods. Although their accuracy and validity have been examined thoroughly, patient-reported information including experiences, preferences, and satisfaction has not yet been investigated in a systematic way. OBJECTIVE: The objective of this systematic review is to investigate the available data and appraise the evidence on patient-reported experiences and preferences following impression taking with intraoral scanners. SEARCH METHODS: Unrestricted search of seven databases (Pubmed, CENTRAL, Cochrane reviews, Scopus, Web of Science, Clinical Trials, and ProQuest) and grey literature were conducted until October 2020. Detailed search strategies were developed for each database. SELECTION CRITERIA: Studies involving individuals of any gender or age, subjected to full arch impression taking with conventional and intraoral scanning methods were eligible for inclusion. DATA COLLECTION AND ANALYSIS: Following the retrieval and selection of the studies, data extraction was performed. Risk of bias assessment was performed using the RoB 2 and ROBINS-I tools. RESULTS: From the initially identified records, nine studies [eight crossover (two of them randomized) and one parallel group] were eventually included in the present systematic review. Randomized studies were shown, overall, to have some concerns regarding bias, whereas the non-randomized studies were found to be at serious risk, mainly because of bias due to confounding. All studies demonstrated some benefit in favour of intraoral scanning compared with conventional techniques. More positive feelings were generally observed with the intraoral scanners regarding smell, taste, sound, vibration, nausea, and queasiness. Overall, comfort assessment mostly favoured digital methods. No differences were found concerning the level of anxiety between the two methods. Among the included studies, time perception was a parameter leading to contradictory results. LIMITATIONS: These emerge due to the nature and characteristics of the information retrieved from the included studies. The validation of the instruments to capture patient-reported outcomes needs to be further elaborated. CONCLUSIONS: Intraoral scanners seem to be a promising new asset in the orthodontic office from the perspective of individuals' experiences and preferences. Nevertheless, to investigate patient-reported outcomes correctly, further high-quality studies are required in the future. REGISTRATION: Open Science Framework (https://osf.io/ayug2/).

The effect of facemask in patients with unilateral cleft lip and palate: a systematic review and meta-analysis.

BACKGROUND: Patients with cleft lip and palate usually present a Class III skeletal pattern. Facemask (FM) is one of the conventional orthodontic treatment modalities used to address the skeletal discrepancy in cleft patients. OBJECTIVE: To investigate the potential effectiveness of FM in unilateral cleft lip and palate (UCLP) patients. SEARCH METHODS: Search without restrictions except language in seven databases since inception and hand searching until January 2019 was conducted. Detailed search strategies were developed for each database which were based on the PubMed strategy and adapted accordingly. SELECTION CRITERIA: Controlled studies assessing the effect of FM in UCLP patients were to be included. DATA COLLECTION AND ANALYSIS: After retrieval and selection of the studies, data extraction was performed. Both angular and linear cephalometric measurements were collected. Weighted mean differences (WMDs) and 95% confidence intervals (CΙs) between treated and untreated UCLP patients concerning the pre- and post-treatment angular measurements of each group were calculated using a random-effects meta-analysis model. The risk of bias in individual studies was assessed using the ROBINS-I tool. RESULTS: From nine eligible studies, five were included in the meta-analysis investigating the use of FM in patients and controls with UCLP (with and without maxillary expansion). Statistically significant differences were evident for SNA/S-N-ss, SNB/S-N-sm, ANB/ss-N-sm, and SN-MP. FM was found to induce an increase of SNA (WMD = 2.12 degrees, 95% CI: 1.58 to 2.66), ANB (WMD = 4.17 degrees, 95% CI: 3.60 to 4.74), and SN-MP angles (WMD = 2.60 degrees, 95% CI: 1.10 to 4.10) and a decrease of SNB angle (WMD = -1.94 degrees, 95% CI: -2.48 to -1.40) in UCLP patients. Low to moderate heterogeneity was observed. LIMITATIONS: They emerge due to risk of bias, exclusion of non-English papers and methodological characteristics of the included papers. CONCLUSIONS: According to the available data, FM seems to improve the sagittal skeletal relationships in UCLP patients, increasing the SNA and ANB angles and decreasing the SNB angle. Moreover, in the vertical dimension, FM increases the SN-MP angle. Regarding dental measurements, there are controversial results. More high-quality studies need to be conducted in order to further clarify the impact of FM on UCLP patients. REGISTRATION NUMBER: PROSPERO: CRD42019131619.

Incidence of incisor root resorption associated with the position of the impacted maxillary canines: A cone-beam computed tomographic study.

INTRODUCTION: The purpose of this study was to examine the incidence and position of lateral and central incisor root resorption owing to the impaction of maxillary canines by means of cone-beam computed tomography and to investigate parameters associated with the respective resorption. METHODS: Sixty-one patients presenting with unilateral or bilateral impacted maxillary canines were evaluated in a university clinic in Athens, Greece, using cone-beam computed tomography scan. No patient had undergone any type of orthodontic treatment in the past. Eleven different parameters related to the existence, grade, and localization of resorption were examined. Logistic regression analysis was used to evaluate potential associations. RESULTS: In our study, canine impaction caused lateral root resorption in 18.5% of the cases examined. Age was associated with localization of the impacted maxillary left canine in a palatal-buccal direction. More specifically, in younger patients, the impacted left canine was more likely to be located in the middle of the maxillary bone, whereas in older patients, it was more likely to be located in the palatal or buccal side of the bone. Lateral root resorption in the apical or middle third was more common in the younger ages, whereas lateral root resorption in the incisal third more common in the older ages. Lateral root resorption increased as the angle between the longitudinal axis of the impacted canine and the adjacent lateral incisor also increased. CONCLUSIONS: Incidence of lateral root resorption was 18.5% in this study population. In younger patients, the impacted canines appear more often in the middle of the maxillary bone, whereas in older patients, the canines are located more often in the palatal or buccal side of the maxilla.

The effect of osteopenia on tooth movement in ovariectomized rats. An experimental study.

OBJECTIVE: The purpose of this experimental study was to investigate in depth the effects of osteopenia related to the rate, as well as to the quality of orthodontic tooth movement, by combining experimental ovariectomy and molar movement in rats. METHODS: Twenty-four six-month-old female Wistar rats were used in this study. The animals were divided into two groups consisting of twelve animals each: Group A (control group) was subjected to orthodontic movement of the upper right first molars. Group B was subjected to orthodontic movement of the upper right first molar following bilateral ovariectomy. Ovariectomy was performed on the first experimental day and the upper right first molars were subjected to orthodontic forces 60 days post-ovariectomy, lasting for 14 days. RESULTS AND CONCLUSION: Direct inspections of the upper jaws, measurements of orthodontic movement of the upper right first molars of Group A and B, as well as histologic examinations of the alveolar bone in the upper right and left first molar regions, showed that osteopenia affects the rate of orthodontic tooth movement, as well as the quality of alveolar bone remodeling, in ovariectomized rats. Specifically, in the ovariectomized animals the alveolar bone of the non-loaded side showed extensive internal resorption, with large marrow cavities, whereas the alveolar bone of the loaded side was dense with almost no marrow cavity and frontal resorption on the surface. It appears that alveolar remodeling after the exertion of orthodontic forces follows the general paradigm of osteoporotic bone remodeling after loading.

Highly cited orthodontic articles from 2000 to 2015.

INTRODUCTION: Identification of highly cited articles based on the h-index and its properties is important for the evaluation of the past, present, and future of any research discipline. In this study, we aimed to identify the h-classic articles in orthodontics. METHODS: One search on the Web of Science identified all articles from 2000 to 2015 in the 89 journals indexed by the 2015 InCites Journal Citation Reports in the scientific area "dentistry, oral surgery, and medicine." A second search was performed in the Web of Science using all mesh terms related to orthodontics. Then, we applied the h-classic method to select the recent articles with the greatest scientific impact in orthodontics. RESULTS: Eighty articles were considered as h-classic articles. They were published in 20 of the 89 dental journals of the 2015 InCites Journal Citation Reports list. Only 36 articles appeared in orthodontic journals: 23 in the American Journal of Orthodontics & Dentofacial Orthopedics (28.8%), 7 in The Angle Orthodontist (8.8%), and 6 in European Journal of Orthodontics (7.5%). Thirty-eight articles originated from Europe, 28 from the Americas, and 14 from the Middle East and Asia. CONCLUSIONS: More than half of fundamental orthodontic research is published in nonorthodontic journals showing that our field is currently limited, and interactions with other research fields should be sought to increase orthodontic research importance and appeal.

Reliability of different radiographic methods for the localization of displaced maxillary canines.

INTRODUCTION: The purpose of this study was to evaluate the reliability of the radiographic images of the main conventional x-ray techniques compared with the information from cone-beam computed tomography (CBCT). METHODS: Twenty patients with unilateral or bilateral impaction of the maxillary canines had radiographic examinations by means of periapical x-rays, occlusal x-rays, panoramic x-rays, and CBCT scans. Three experienced orthodontists examined all x-rays from each patient and evaluated the radiographic images of the impacted canines. The examiners were asked to detect resorption in adjacent teeth and the buccal-palatal position of the impacted canines. Agreement between examiners was statistically tested. RESULTS: Different diagnoses were produced by the 3 examiners regarding localization of the impacted canines and the presence or absence of root resorption of the adjacent teeth in conventional radiographic images. It appears that whereas panoramic x-ray is more sensitive in detecting resorption and tooth position, occlusal and periapical imaging have higher specificity and positive predictive value. The examiners were in good or excellent agreement when occlusal and periapicals were used for the definite diagnosis of resorption and tooth position. There was no disagreement of the examiners in CBCT images, which were used as the gold standard. CONCLUSIONS: Conventional radiographic methods demonstrated a more subjective diagnostic procedure compared with CBCT images. CBCT is a more accurate and precise examination method compared with conventional radiography for the localization of impacted teeth and root resorption of the adjacent teeth.

Open versus closed surgical exposure of palatally impacted maxillary canines: comparison of the different treatment outcomes-a systematic review.

Objective: This study aims to compare the effectiveness of two different canine exposure techniques (open and closed) regarding periodontal outcomes, duration of surgical treatment and canine's eruption, patient's inconvenience, aesthetics, and orthodontic treatment complications. Search methods: Electronic database searches of published and unpublished literature were performed. The reference lists of eligible studies were hand searched for additional studies. Selection criteria: Randomized clinical trials (RCTs), quasi-randomized clinical trials (Q-RCTs) and non-randomized trials of prospective and retrospective design with patients of any age that compared group with palatally impacted canines treated by open exposure to a similar group treated by closed exposure technique were selected. There was not any restriction in language or year of publication. Data collection and analysis: Study selection, data extraction, and risk of bias assessment were performed individually and in duplicate. Results: Search strategy resulted in 159 articles and nine articles were selected for the final analysis. They were three non-randomized trials, one Q-RCT, and two reports of another Q-RCT and three reports of one RCT. The level of reported evidence was high for the RCT and one Q-RCT but poorer for the other trials. Four articles reported periodontal outcomes, three searched the duration of surgical procedure, two the duration of canine eruption, two investigated patient's inconvenience, two reported on failure rates and two addressed aesthetic outcomes. The results are inconsistent and there is considerable disagreement for the majority of the outcomes among studies. Conclusion: According to existing articles we may conclude that there is no difference between the two techniques regarding the periodontal outcomes and aesthetic appearance. The surgical procedure is shorter in the open exposure group and the amount of postoperative pain during the first day is similar between the open and closed surgical exposure patients. However, these conclusions are based on two single trials with high level of evidence, while the rest of the studies present high risk of bias.

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.

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.

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.

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.

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.

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.

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.

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.