Spontaneous Mandibular Dentoalveolar Changes after Rapid Maxillary Expansion (RME), Slow Maxillary Expansion (SME), and Leaf Expander-A Systematic Review.

BACKGROUND: This systematic review aims to analyze the spontaneous dentoalveolar changes in the mandibular arch after maxillary expansion in growing patients obtained with different expansion protocols: Rapid Maxillary Expansion (RME), Slow Maxillary Expansion (SME), and Leaf Expander. METHODS: The study adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Eligibility criteria were established in the PICO format, involving patients who underwent slow, rapid, or leaf maxillary expansion during the mixed or early permanent dentitions. A comprehensive search of electronic databases and manual searches was conducted up to December 2023. The outcome measures included inter-mandibular first permanent molar width, inter-deciduous molar and canine width, arch perimeter, and arch length; both short- and long-term results were considered. The articles that met the inclusion criteria were included in this systematic review and were qualitatively evaluated using a methodological quality scoring system with a 13-point scale. To assess the inter-examiner agreement concerning the article selection and the qualitative assessment of the included studies, Kappa statistics were computed. RESULTS: A total of 1184 articles were identified through electronic and manual searches. After the removal of duplicates and the initial examination of the titles and abstracts, 57 articles were considered for the full text analysis, and according to the eligibility and exclusion criteria, 22 studies were finally selected, composed of 8 randomized controlled trials (RCTs) and 14 retrospective/case-control studies. The qualitative assessment of the included studies showed the following scores: 6 papers have high research quality, 5 have moderate quality, and 11 have low quality. SME demonstrated negligible mandibular changes, with less than 1 mm variation on average (range 0.46-2.00 mm) in the selected parameters and relapses observed in the long term. RME induced more significant increases, particularly in intermolar width greater than 1 mm, which ranged between 0.93 and 3.3 mm, and good stability over the long term. Leaf Expander exhibited promising short-term lower intermolar width increases greater than 1 mm and ranged from 0.5 to 1.69 mm, but long-term stability was not thoroughly evaluated. CONCLUSIONS: SME results in negligible short- and long-term effects, while RME, especially with Haas-type appliances, exhibits significant intermolar width increases that remain stable over the years. Leaf Expander shows short-term lower intermolar width increases, requiring further investigation into long-term stability.

Comparison of the skeletal, dentoalveolar, and periodontal changes after Ni-Ti leaf spring expander and rapid maxillary expansion: a three-dimensional CBCT based evaluation.

BACKGROUND: The aim of the present study was twofold:(1) three-dimensionally evaluate the quantitative skeletal and dentoalveolar changes after Ni-Ti leaf spring expander (leaf expander) and rapid maxillary expansion (RME) in mixed dentition patients;(2) analyze the modifications of the buccal alveolar bone plate of the maxillary first permanent molars. METHODS: Patients who underwent CBCT scans before and after maxillary expansion were randomly selected from the records archived at the Department of Biomedical Surgical and Dental Sciences, University of Milan, Italy. Inclusion criteria were the following: no systemic disease or syndromes; maxillary transverse deficiencies (difference between the upper intermolar width and the lower intermolar width of at least 3 mm and/or clinical need based on radiographic evaluation), early mixed dentition with ages between 7 to 10 years old; cervical vertebra maturation stage (CVMS) 1 or 2; no pathologic periodontal status; skeletal class I or II; maxillary expander cemented on the upper second deciduous molars. Exclusion criteria were the following: patients with pubertal or post-pubertal stage of development (CVMS 3-6); late deciduous or late mixed dentition, impossibility to use the second primary molar as anchorage; skeletal class III malocclusion; craniofacial syndromes; patients unable to be followed during the treatment period. Twenty-three patients treated with Leaf Expander, 11 males (mean age 7.8 ± 0.6 years) and 12 females (mean age 8.1 ± 0.8 years), met the inclusion criteria and constituted the case group. Twenty-four (control group) treated with conventional RME, 12 males (mean age 8.4 ± 0.9 years) and 12 females (mean age 8.1 ± 0.7 years). The paired-sample T test was used for intra-group comparison to evaluate the difference between before (T1) and after (T2) maxillary expansion. Independent sample t-test was computed to perform between groups comparison of the skeletal, dentoalveolar, and periodontal changes. RESULTS: The Leaf Expander and RME group showed a significant increase between T1 and T2 for most of the skeletal and dentoalveolar variables. Concerning the skeletal variables only the RME demonstrated a significant increase at the level of the posterior nasal (PNW) and apical base width (PABW) and maxillary mid-alveolar width (MMW). Despite this, when compare with the Leaf Expander, the RME group exhibited a statistically larger width increase for only two skeletal parameters: PNW (p = 0.03) and MMW (p = 0.02). No significant changes at the periodontal level were found in either group. CONCLUSIONS: According to the current research, the authors confirm the effectiveness of the Leaf Expander and RME to produce similar skeletal and dentoalveolar effects in mixed dentition subjects. Moreover, the devices anchored to deciduous teeth did not reduce the thickness and height of the buccal bone at the level of the maxillary permanent first molars in either of the two groups.

Three-dimensional evaluation of the maxillary sinus in patients with different skeletal classes and cranio-maxillary relationships assessed with cone beam computed tomography.

The objective was to evaluate the relationship between the dimensions of the maxillary sinuses (MSs) and various cephalometric parameters. MS volume (MSV), MS surface (MSS), linear maximum depth (LMD), linear maximum width (LMW), and linear maximum height (LMH) were calculated on CBCT scans of 99 adults. Two sets of two-way (ANOVA) assessed the influence respectively of ANB and SNA angles and of the gender on MS dimensions. Pearson's correlation was calculated between MS dimensions and different cephalometric variables. Reliability and accuracy of the proposed method was tested with intra-operator and inter-operator intraclass correlation coefficient (ICC). Two-way ANOVA showed no statistically significant difference in MSV, MSS and LMH between ANB groups, whilst males were associated with bigger sinuses. LMW showed statistically significant difference in both ANB and gender groups. LMD showed no statistically significant difference. The second Two-way ANOVA showed significantly larger MSV, MSS and LMD in patients with increased or reduced SNA angle but not between genders. LMW and LMH also showed a significant difference between genders. All linear measurements showed a significant interaction of the two factors. The intra-observer and inter-observer ICC scored high for all the tested measurements. MSV and MSS showed a positive correlation with S-N, PNS-A, S-Go, N-Me, N-Ans and the distance between Mx points. LMW had a negative correlation with Ba-S-N angle and N-Me, LMH with Ba-S-N angle, S-Go and Mx r-Mx l and LMD with N-Me and N-ANS. LMW had a positive correlation with Mx r-Mx l, LMH with S-N, S-N^Ans-Pns, N-Me, N-Ans and LMD with S-N, Ba-S-N, PNS-A, S-Go and distance between Mx points. In conclusion, MSV and MSS did not differ between the three skeletal classes, males showed significantly larger MS than in females. Concerning the influence of the cranio-maxillary relationship (SNA) and gender on MS dimension, subjects with a retrusion (SNA < 80°) or protusion (SNA > 84°) of the maxillary alveolar bone had larger MSV, MSS, LMW, LMH and LMD than subjects with a normal cranio-maxillary relationship (SNA 82 ± 2°). A statistically significant high positive correlation was observed between S-N, Pns-A, S-Go, Mx-R/Mx-r and MS dimension. Further studies that evaluate similar outcomes in different races may be able to enrich our knowledge on this topic.

Evaluation of Enamel Surfaces after Different Techniques of Interproximal Enamel Reduction.

According to the literature, interproximal enamel reduction (IER) has become a consolidated technique used in orthodontic treatments to gain space in particular situations such as dental crowding, non-extractive therapies, tooth-size discrepancies, and prevention of dental relapse. There are different methods to realize stripping, and enamel surfaces resulting after this procedure can be analyzed with SEM. The aim of this study was to analyze how different devices of IER leave the surface of the teeth. One hundred and sixty freshly extracted, intact human lower incisors were included in the study, fixed in a plaster support, and then processed with four different techniques of enamel reduction and finishing. Then, they were divided randomly into eight groups (A1-A2, B1-B2, C1-C2, D, and E), each containing twenty teeth. The A, B, and C groups were divided into two subgroups and then all the teeth were observed at SEM. Each digital image acquired by SEM showed that there were streaks on the surfaces, due to the cutter used. The results of this study showed that only group C2 (tungsten carbide bur followed by twelve steps of medium-fine-ultrafine 3M Soft Lex disks) has a few line, which is very similar to group E (untreated group), while the other groups have a lot of lines and show a rougher final surface.

Evaluation of Masticatory Muscles in Adult Patients with Maxillary Hypoplasia Treated with Surgically Assisted Rapid Maxillary Expansion (SARME): A Retrospective Study.

Aim: The aim of the present study was to investigate modifications in electromyographic activity of temporal and masseter muscles before and after surgically assisted rapid maxillary expansion (SARME) in adult subjects. Materials and Methods: Data from 20 patients with unilateral posterior crossbite were selected retrospectively from the Orthodontics Department of the University of Genoa and the Department of Biomedical Surgical and Dental Sciences of the University of Milan, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico Milan. Inclusion criteria were set as skeletal class I; adult patients (age > 18); good general health; patients with a transverse maxillary deficiency with unilateral posterior crossbite and maxillary constriction ≥ 5 mm; Superficial electromyographic (EMG) examinations at T0 and T1. Exclusion criteria were smoking, metabolic bone diseases (e.g., hyperparathyroidism, vitamin C deficiency), chronic use of corticoids before or during treatment, parafunctional habits (e.g., bruxism), and temporomandibular joint dysfunction. The Shapiro−Wilk test was performed to check whether the data were normally distributed. Differences for each variable before and after SARME were analyzed with a paired t-test (p < 0.05). Results: The statistical analysis demonstrated no statistically significant differences between the EMG values taken before and after SARME regarding the standardized electrical activity of the masticatory muscles (masseter and anterior temporalis (p > 0.05)). Conclusions: Considering the specific conditions of this study, it can be concluded that SARME did not alter the EMG activity of the masseter and temporal muscles. The present study has shown that the masticatory musculature evaluated after approximately 8 months of therapy can adapt well to SARME.

Method Presentation of a New Integrated Orthodontic-Conservative Approach for Minimally Invasive Full Mouth Rehabilitation: Speed Up Therapy.

The materials available today allow for extensive oral rehabilitations in a non-invasive way, and often an orthodontic preparation is useful and, thanks to the use of clear aligners, is predictable and comfortable. A preliminary study of the wax-up, mock-up, and set-up allow the clinician to plan every aspect of the treatment in detail. Furthermore, the procedure offers the patient an intuitive and understandable view of the expected final result. The new proposed method, called "speed up therapy", allows for the integration of the orthodontic set-up with the mock-up technique, simulating the occlusal and aesthetic components of the planned restoration, in all details. The clinical case presented, demonstrates step by step the predictability and clinical reliability of the proposed procedure. The final clinical result coincides exactly with the initial mock-up and demonstrates that the proposed method is predictable and reliable. The correct execution of the technique is rigorously customized, and its success is operator dependent, both for the clinical aspects and for the dental laboratory. Thus, the visualization of the objectives of the treatment constitutes a decisive support for the clinician and provides the patient with the possibility of benefiting from an immediate improvement by making it easier for them to accept a treatment plan. The visualization also includes an orthodontic phase that potentially lengthens the treatment but makes the realization more conservative and predictable.

Oral ecological environment modifications by hard-cheese: from pH to microbiome: a prospective cohort study based on 16S rRNA metabarcoding approach.

BACKGROUND: The oral ecosystem conditions dental health, and is known to be positively modified by oral hygiene which cannot always be performed between meals, especially outside home. It is therefore important to identify the practices to be adopted to influence the oral environment in an anticariogenic direction. Milk and cheese are considered functional foods and have a role on oral health. There are several mechanisms by which cheese exerts its beneficial effects on teeth. The aim of the present study was to examine whether short term consumption of hard cheese would affect the oral pH and microbial flora of healthy adults modifying ecological oral environment. The Next Generation Sequencing (NGS) approach was applied to study the effect of Italian Grana Padano (GP), as a prototype of typical hard cheese, on the oral microbiota composition. Finally, we explored Streptococcus mutans/sanguinis ratio as a marker of protective biofilm composition. METHODS: Nine oral-healthy adults were instructed to eat 25 gr of GP cheese for 5 consecutive days. Three time points were chosen for supragingival samples collection and pH measurement. 16S rRNA-gene sequences were obtained both from oral samples and GP cheese using the MiSeq platform and analyzed against the expanded Human Oral Microbiome Database (eHOMD). ProgPerm was used to perform statistical analyses to investigate strain differential representation after cheese consumption. RESULTS: Taxonomic analyses of the oral microbiota revealed that Firmicutes was the most abundant phylum, followed by Proteobacteria and Actinobacteria. GP cheese significantly modifies oral pH, causing a shift toward basic conditions which are kept for a few hours. The Streptococcus mutans/Streptococcus sanguinis ratio lowers in the last observed timepoint. CONCLUSION: Our results reveal that a portion of GP cheese eaten after dinner provides important micronutrients (i.e. calcium, vitamins and some aminoacids such as arginine) and changes oral pH toward basic conditions, resulting in a light modification of the oral microbiome towards the reduction of the overall amount of acidophilic bacteria. Furthermore, the S. mutans/S. sanguinis ratio is reduced, contributing to obtain a more protecting environment towards caries establishment and evolution.

A CBCT based analysis of the correlation between volumetric morphology of the frontal sinuses and the facial growth pattern in caucasian subjects. A cross-sectional study.

BACKGROUND: The aim of this study was to evaluate the relationship between frontal sinus shape and facial growth pattern. METHODS: The three-dimensional examination was carried out by means of 80 CBCT scans selected from a sample of 1247 records of patients treated, for different reason, at the Department of Biomedical Surgical and Dental Sciences at University of Milan, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico Milan. The sample (age ranges between 12 and 40 years) was divided according to gender and age in four groups (12-17, 18-20, 21-30, 31-40). Left and right frontal sinus volume (VOL), surface (SUP) and linear maximum width (XMAX), depth (ZMAX) and height (YMAX) were calculated using Mimics Research 17.0 (Materialise N.V., Leuven, Belgium). Cephalometric analysis has been performed for all subjects to categorize the patients depending on their facial growth pattern. Univariate and multivariate regression analysis were performed to investigate any association of frontal sinuses measurements (height, width, depth, volume and surface) and cephalometric variables. P value < 0.05 was considered statistically significant. RESULTS: A total of 160 frontal sinuses were measures in 80 patients: 40 men and 40 women, average age of 23.5 ±14.6. Globally the frontal sinuses had the following average dimensions: volumes of 9055.8 ± 6505 mm3 and surfaces of 3820.3 ± 2125 mm2. The statistical analysis showed that frontal sinus volume was statistically significant (p=0.003) greater for male (11,425 mm3) than female (6597.5 mm3). Similarly, the surface showed to be greater in men than in women (p=0.005). No correlation between age and frontal sinuses characteristics has been found. A statistically significant (p<0.05) increase of frontal sinus depth, surface and volume was correlated with SNB angle. In addition, frontal sinus volume increased in subjects with greater anterior skeletal dimension values and with a superior length of the cranial base. Furthermore, a decrease of ANB has been found related to an increase in frontal sinus volume (p=0.04). CONCLUSIONS: The present study showed a correlation between frontal sinuses dimensions and craniofacial aspects, despite the inter-individual variability of their morphology. The results suggested that young adults in whom the frontal sinuses have reached their maximum size, while vertical growth continues, a larger frontal sinus may be associated with future vertical growth.

Evaluation of the effectiveness of a novel mouth rinse containing hyaluronic acid and hydrogen peroxide on gingivitis: A randomized pilot controlled trial.

OBJECTIVE: To evaluate and compare the effectiveness of a mouth rinse with hydrogen peroxide (H2 O2 ) and hyaluronic acid (HA) versus a placebo mouth rinse on gingivitis. MATERIAL AND METHODS: This was a 21-day, double blind, randomized, two-arm parallel allocation placebo-controlled trial of 50 study participants with a diagnosis of plaque-induced gingivitis. Patients were randomly allocated to the test group or the placebo group and were assessed at three time points over the course of the study by the same operator, at baseline (T0), 7 days (T1), and 21 days follow-up (T2). Primary outcomes of the trial were improvement in gingivitis and plaque accumulation. RESULTS: In both groups there was a decrease in gingival and plaque indices but the combination of the two actives (H2 O2 /HA) proved to be more effective against gingivitis (p = 0.001). Regarding plaque index, the differences between the test product and placebo were not statistically significant (p = 0.084). Besides, the new mouthwash was considered palatable, no adverse events were registered over the 21-day period. CONCLUSIONS: The H2 O2 + HA product was more effective in reducing gingivitis when compared to a placebo while no differences were observed for plaque accumulation.

Correlation between facial growth patterns and cortical bone thickness assessed with cone-beam computed tomography in young adult untreated patients.

BACKGROUND: The vertical facial growth pattern is one of the most important issue in the orthodontic diagnosis and treatment. Previous studies investigated the association between interdental bone thickness and facial divergence using mainly bidimensional analysis. When two-dimensional dental radiographic views are not sufficient for diagnosis and measurements, cone-beam computed tomography (CBCT) images should be used to assess the alveolar bone structure three-dimensionally and with high accuracy and reliability.The aim of the present study was to evaluate the correlation between alveolar bone thickness and facial divergence in young adults untreated patients using a three-dimensional method analysis with CBCT images. METHODS: Records of 30 untreated patients (mean age 16 ± 2 years) with Angle Class I and mild to moderate crowding were analyzed. Subjects were classified as hypodivergent (<39˚), normodivergent (41 ± 2˚), and hyperdivergent (>43°). according to the inter-maxillary angle between the sagittal maxillary plane (ANS-PNS) and the mandibular plane (GN-ME). The alveolar bone thickness measurements were taken for the buccal and palatal/lingual surfaces of maxillary and mandibular anterior teeth. Axial-guided navigation (AGN) was used to locate all landmarks using a specific software (Horos 3.0). RESULTS: The statistical analysis showed a significant difference between the hypodivergent and hyperdivergent group regarding buccal bone height (P = 0.005), buccal apical bone thickness (P = 0.003) and palatal mid-root bone thickness (P = 0.006). Moreover, buccal bone height (P = 0.006) was found to be statistically significant different in normodivergent compared with hypodivergent individuals. CONCLUSIONS: Facial types were found to be correlated with alveolar bone thickness. The hyperdivergent subjects presented thinner alveolus bone in the anterior maxilla and at almost all sites in the mandible. Clinicians should be aware of the possibility of thin cortical bone plates in hyperdivergent patients, reducing antero-posterior movements to avoid fenestration and dehiscence.

Correlation between Malocclusion and Allergic Rhinitis in Pediatric Patients: A Systematic Review.

BACKGROUND: Oral breathing, nasal obstruction and airway space reduction are usually reported as associated to allergic rhinitis. They have been linked to altered facial patterns and dento-skeletal changes. However, no firm correlation based on the evidence has been established. This systematic review has been undertaken to evaluate the available evidence between malocclusion and allergic rhinitis in pediatric patients. METHODS: The research refers to Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines, databases (Medline, Cochrane Library, Pubmed, Embase and Google Scholar) were screened, the quality was evaluated through Quality Assessment of Diagnosfic Accuracy Studies (QUADAS-2). RESULTS: The articles selected (6 out of initial 1782) were divided on the basis of the study design: two observational randomized study, three case-control study, one descriptive cross-sectional study, and one longitudinal study. A total of 2188 patients were considered. Different results were reported as related to allergic rhinitis ranging from a higher incidence of dental malocclusion, to an increase of palatal depth, and in posterior cross-bite about anterior open-bite and to longer faces and shorter maxillas. CONCLUSIONS: Most of the studies selected found a rise in the prevalence of both malocclusion and allergic rhinitis in children. However, the level of bias is high, impaired by a poor design and no conclusive evidence can be drawn.

Buccal Bone Changes Around First Permanent Molars and Second Primary Molars after Maxillary Expansion with a Low Compliance Ni-Ti Leaf Spring Expander.

Background: Vestibular bone thickness changes and dento-alveolar buccal tipping of second primary molars and of first molars after maxillary expansion performed with a slow maxillary expansion protocol was investigated. Methods: Twenty patients (mean age 7.3 ± 0.9 years old; 9 male and 11 female) were treated according to the Leaf Expander protocol. Buccal alveolar bone thickness (BT), buccal alveolar bone height (BH), inter-dental angle (TIP), and inter-molar width (IW) regarding first molars and second primary molars were calculated before and after expansion on cone beam computed tomography (CBCT) images. Descriptive statistics and paired t-tests were used to assess changes between the pre-treatment and post-treatment measurements. Results: Bone thickness vestibular to second primary molars and intermolar width of both teeth were the only variables that showed statistically significant changes. Conclusions: It appears that buccal bone thickness vestibular to first molars was not significantly reduced after maxillary expansion with the Leaf Expander. The clinical use of a slow maxillary expander with Ni-Ti springs appears efficient and safe in in the correction of maxillary hypoplasia during mixed dentition.

A Scoping Review of Respirator Literature and a Survey among Dental Professionals.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus was discovered in China in late 2019 and subsequently triggered a global pandemic. Dentists, like many other health professionals, are at an increased risk of contracting the virus as they work in close proximity to patients, especially when performing aerosol-generating procedures. Thus, in order for dentists to protect themselves and their patients, it is recommended that practitioners wear filtering facepiece 2 (FFP2) respirators. The prolonged use of these FFP2 respirators has been linked to several side effects. The aim of this paper is to assess the perceived experience associated with N95/FFP2 respirators based on the available literature and data collected through an online survey completed by Italian dental professionals. Articles were included up to May 2020 and literature searches were conducted through The National Library of Medicine, Cochrane Central Register of Controlled Trials, and Embase databases. The search terms included COVID-19, respirators, masks, and discomfort. An online survey was administered to 256 Italian dentists. The results from this survey were in agreement with the available literature. The findings concurred that the prolonged use of respirators was associated with headaches (47.5%), severe exertion and discomfort (50.8%), moderate concentration problems (54.3%), moderate breathing difficulties (63.5%), and consequently, an impaired work ability (85.5%). These findings were not influenced by the number of hours spent wearing the respirator. Despite several side effects, FFP2 respirators are fundamental in protecting dentists and their importance was acknowledged.

Volumetric Changes in the Upper Airways after Rapid and Slow Maxillary Expansion in Growing Patients: A Case-Control Study.

The aim is to evaluate changes in the volume of the upper airways before and after slow maxillary expansion (SME) obtained with the flexible properties of a nickel titanium leaf spring and rapid maxillary expansion (RME) with a conventional Hyrax appliance in growing patients. The records of 1200 orthodontic patients undergoing maxillary expansion from 2018 to 2019 were analyzed; among these pre and post treatment CBCT scans of 22 patients (mean age 8.2 ± 0.6 years old) treated by SME were compared with those obtained from 22 patients (mean age 8.1 ± 0.7 years old) treated by RME banded on the second primary molars. The following inclusion criteria were used: Maxillary transverse constriction, good general health, and no previous orthodontic treatment. Volumes of nasal cavity (NCavV), nasopharynx (NsPxV), and right and left maxillary sinuses (MSV) were calculated with ITK-SNAP. Shapiro-Wilk test revealed a normal distribution of data in each group. Paired t-test was used for within-group comparisons and independent t-test for between-group comparisons. Statistically significant increases occurred in NCavV, NsPxV, and MSVs after treatment with both appliances. No statistically significant difference between the appliances occurred in NCavV, NsPxV, and MSVs. Method error was considered negligible (mean intra-operator and inter-operator intraclass correlation coefficient were 0.928 and 0.911, respectively). It appears that both appliances produce similar effects on the different segments of the upper airway tract.

Biomimetic Effect of Nano-Hydroxyapatite in Demineralized Enamel before Orthodontic Bonding of Brackets and Attachments: Visual, Adhesion Strength, and Hardness in In Vitro Tests.

Dietary habits with high consumption of acidic food can induce in orthodontic patients an increased risk of demineralization lesions around orthodontic brackets and bands. The purpose of the present laboratory study is to assess the in vitro visual efficacy of a biomimetic nano-hydroxyapatite remineralizing solution in a hypomineralized enamel surface and its effect on adhesion of fixed orthodontic appliances and on enamel microhardness. Intact teeth were demineralized, and subsequently the areas of demineralization were visually recorded using a 0-100 scale. Subsequently, a remineralizing solution (Biorepair® Repair Shock Treatment) was applied for ten minutes once a day/for one week per month for a total remineralizing treatment of 3 months. Visual effects were recorded. Moreover, bond strength was recorded and adhesive remnant index scores were measured for both orthodontic brackets and composite attachments both before demineralization and after demineralization and application of remineralizing solution. Also, Vickers microhardness was measured. All data were submitted to statistical analysis. The application of remineralizing solution induced a significant in vitro reduction of demineralized areas after the first week of application. No significant differences between untreated enamel surfaces and remineralized surfaces were detected after 2 months of remineralizing treatment. Bond strength values were significantly reduced for both brackets and attachments after remineralizing treatment. However, attachments showed higher adhesion values than brackets in both conditions tested. Remineralized enamel showed significantly higher microhardness values than demineralized enamel and lower values than intact enamel.

Assessment of the Stability of the Palatal Rugae in a 3D-3D Superimposition Technique Following Slow Maxillary Expansion (SME).

The Palatal Rugae are considered a useful human identification marker for both orthodontists and forensic personnel. The principal aim of the present study was to evaluate the stability of palatal rugae with a 3D-3D superimposition procedure following Slow Maxillary Expansion (SME), in order to assess whether they kept their uniqueness and validity for human identification, even after a specific dental treatment. For this purpose, a sample of 27 digital dental models - belonging to growing patients (13 males and 14 females), aged between 8.5 and 15 years, who underwent SME therapy - was retrospectively studied and compared with a control group of 27 untreated subjects - (13 males and 14 females). Digital dental models were obtained pre-treatment and at device removal; both were processed by means of an intraoral scanner. A superimposition procedure was thus performed to reach the minimum point-to-point distance between two models of palatal rugae. Intra- and inter-observer differences were statistically analyzed by paired Wilcoxon test and Intra-class Correlation coefficient (ICC), showing values larger than 0.93. There was no difference in Root-Mean-Square (RMS) values between untreated control subjects and subjects treated with Leaf Expander (p = 0.062). A RMS value of 0.43 was the threshold to distinguish the pooled group ("Untreated" and "Leaf") from any mismatch. According to the obtained results, this study failed to reject the null hypothesis and presented no differences between the RMS values of the Test group and the RMS values of the untreated control group. This work highlighted the usefulness of 3D superimposition procedure for purposes of human identification, in subjects undergoing dental treatment. However, keeping in sight the forensic use of this technique as a helpful probation element in court, further studies should be performed to confirm these findings.

A multicenter, prospective, randomized trial of pain and discomfort during maxillary expansion: Leaf expander versus hyrax expander.

BACKGROUND: Pain suffered by the young patient is the most frequent symptom during orthodontic treatment and is the one that most frightens children and causes worry in their families. AIM: To investigate pain perception and function impairment during the first week of activation of two palatal expansion screws. DESIGN: A total of 101 subjects were randomly divided into two groups: RME group included patients treated with the standard hyrax expansion screw and LEAF group included patients treated with Leaf Expander appliance. Pain intensity was assessed via the Wong-Baker scale. A questionnaire on oral function impairments was also compiled by the patients. RESULTS: The Pain Scale analysis showed that patients in the RME group suffered from a significantly higher level of pain than those in the LEAF group (88.6% vs 25%, P < .01). RME group showed highest pain indexes from day 1 to day 4 (51.4% RME vs 9.7% LEAF suffered at least once from strong pain in the first 4 days, P < .01). Furthermore, oral functions were similarly affected in both groups. CONCLUSIONS: Pain reported during maxillary arch expansion is influenced by clinical activation protocol and by the screw type. Patients treated with Leaf Expander reported significantly lower pain level in the first 7 days of treatment.

Comparison of a tridimensional cephalometric analysis performed on 3T-MRI compared with CBCT: a pilot study in adults.

OBJECTIVE: Since the introduction of cone-beam computed tomography (CBCT) in dentistry, this technology has enabled distortion-free three-dimensional cephalometric analysis for orthodontic and orthognathic surgery diagnosis. However, CBCT is associated with significantly higher radiation exposure than traditional routine bidimensional examinations for orthodontic diagnosis, although low-dose protocols have markedly reduced radiation exposure over time. The objective of this preliminary feasibility study is to compare the accuracy and diagnostic capabilities of an already-validated three-dimensional cephalometric analysis on CBCT to those of an analysis on 3-T magnetic resonance imaging (3T-MRI) to assess whether the latter can deliver a comparable quality of information while avoiding radiation exposure. MATERIALS AND METHODS: In order to test the feasibility of three-dimensional cephalometry on 3T-MRI, 18 subjects (4 male; 14 female) with mean age 37.8 ± SD 10.2, who had undergone both maxillofacial CBCT and maxillofacial 3T-MRI for various purposes within 1 month, were selected from the archive of the Department of Dentistry and Maxillofacial Surgery of Fondazione Ospedale Policlinico Maggiore, IRCCS, Milano, Italy. A three-dimensional cephalometric analysis composed of ten midsagittal and four bilateral landmarks and 24 measurements (11 angular, 13 linear) was performed on both scans using Mimics Research® v. 17.0 (NV, Technologielaan 15, 3001 Leuven, Belgium). Cephalometric analysis was performed twice by two independent orthodontists for each scan, and each orthodontist repeated the measurements 3 weeks later. Statistical analysis was performed with SPSS® 20.00 for Windows (IBM® Corporation, Sommers, NY, USA). A Bland-Altman test for each cephalometric value was performed to assess the agreement between the procedures. The intraclass correlation coefficient (ICC) was used to assess interobserver and intraobserver reliability. The coefficient of variation was used to evaluate precision. RESULTS: Both procedures showed good reliability, with mean intraobserver ICCs of 0.977/0.971 for CBCT and 0.881/0.912 for MRI. The average interobserver ICCs were 0.965 for CBCT and 0.833 for MRI. A Bland-Altman analysis for the cephalometric tracing revealed a similar range of agreement between the two modalities; the bias range (mean ± SD) was - 0.25-0.66 mm (0.174 ± 0.31) for distances and - 0.41-0.54° (0.12 ± 0.33) for angles. CONCLUSIONS: Within the main limitation of this pilot study, that is, the small sample, it is possible to state that cephalometric measurements on 3T-MRI seem to possess adequate reliability and repeatability and that they show satisfying agreement with values measured on CBCTs. An MRI examination does not expose patients to ionizing radiation and could provide an alternative to CBCT for three-dimensional cephalometrics in the future.