Evaluation of mandibular growth in a prepubertal Class I and Class II population: a longitudinal analysis.

OBJECTIVE: This study aims to identify the presence, timing, and magnitude of a prepubertal mandibular growth spurt in a Class I and Class II population. METHODS: From the Burlington and Iowa Growth study of the AAOF Craniofacial Growth Legacy Collection, 83 Class I subjects (37 females and 46 males) and 32 Class II subjects (18 males and 14 females) were identified, as having at least seven consecutive annual lateral cephalograms taken from 5 to 11 years of age. Only subjects with a normodivergent facial pattern were considered. A customized cephalometric analysis was performed, and total mandibular length, defined as the distance between Condylion (Co) and Gnathion (Gn), was calculated. RESULTS: Overall, a significant early peak of mandibular growth was present in all the subjects analysed both in Class I (4.69 mm for males and 4.18 mm for females; P < .05) and in Class II (5.85 mm for males and 4.05 mm for females; P < .05). No differences between males and females were found for the timing of this peak (7 years for Class I and Class II females and 7 years for Class I and 6.5 years for Class II males). In males, a significantly larger peak was observed in Class II than Class I subjects (P = .007). LIMITATIONS: The main limitations of this study were the impossibility of using a suitable growth indicator to identify the timing of the early mandibular growth peak and the limited Class II records retrievable. CONCLUSION: This investigation suggests that a prepubertal mandibular growth peak is consistently present in both Class I and Class II males and females of clinically significant magnitude. Despite that, chronological age confirms to be unsuitable to identify this peak.

Bone quality in relation to skeletal maturation in palatal miniscrews insertion sites.

INTRODUCTION: This study aimed to investigate the relationship between bone density and quantity at the insertion sites of palatal miniscrews and skeletal maturation-evaluated with the middle phalanx maturation method-in growing patients. METHODS: Sixty patients were analyzed as having a staged third finger middle phalanx radiograph and a cone-beam computed tomography of the maxilla. On the cone-beam computed tomography, a grid was designed to parallel the midpalatal suture (MPS) and posterior to the nasopalatine foramen, both on the palatal and lower nasal cortical bones. Bone density and thickness were measured at the intersections, and medullary bone density was also calculated. RESULTS: Of patients in MPS stages 1-3, 67.6% showed a mean palatal cortical thickness of <1 mm, whereas in 78.3% of the patients in stages 4 and 5, it was >1 mm. The nasal cortical thickness showed a similar trend (MPS stages 1-3: 62.16% <1 mm; MPS stages 4 and 5: 65.2% >1 mm). There was a significant difference in the density of the palatal cortical bone between MPS stages 1-3 (1272.05 ± 191.13) and stages 4 and 5 (1572.33 ± 274.89) and in nasal cortical density between MPS stages 1-3 (1428.09 ± 198.97) and stages 4 and 5 (1597.97 ± 267.75) (P <0.001). CONCLUSIONS: This study revealed a correlation between skeletal maturity and maxillary bone quality. MPS stages 1-3 have lower palatal cortical bone density and thickness but high nasal cortical bone density values. MPS stage 4 and, even more, stage 5 show increasing palatal cortical bone thickness and palatal and nasal cortical bone density values.

Duration of stages of the Middle Phalanx Maturation method in a contemporary population: A 6-year longitudinal analysis.

OBJECTIVE: To determine the duration and age at the beginning of each stage corresponding to the circumpubertal period in the Middle Phalanx Maturation method (MPM) and to assess the differences between males and females. MATERIALS AND METHODS: Sets of X-rays of the middle phalanx of the third finger taken at 6-month intervals were analysed for 246 skeletal Class I subjects (102 females and 144 males) between 9 and 15 years of age. After staging, the duration of each stage was derived from chronological ages, and the difference between males and females for both duration and age at the beginning of each stage was investigated. RESULTS: The median duration for MPS2 and MPS3 was 1 year for both sexes, while MPS4 showed a median duration of 1 year in females and 9 months in males, with no significant differences between the sexes. Mean age at the beginning of MPS2 was 10y11m for females and 11y11m for males; for MPS3, it was 11y8m for females and 13y1m for males; for MPS4, it was 12y9m for females and 13y11m for males; for MPS5, it was 13y4m for females and 14y3m for males. The differences between the sexes were statistically significant for all the stages (P < .001). CONCLUSIONS: This study confirms, with relevant sample size, the median duration of 1 year for each MPM stage from MPS2 to MPS4. Despite the distinctive interindividual variability, the interquartile range is 6 months or less for all but one interval, confirming the soundness of the results.

Prevalence of oral behaviours in general dental patients attending a university clinic in Italy.

BACKGROUND: Oral behaviors represent a diverse array of habits beyond the physiological behaviors of the stomatognathic system. OBJECTIVE: To describe the prevalence of different oral behaviors, as reported with the Oral Behavior Checklist (OBC-21), in a convenience sample of patients attending an Italian university clinic for routine dental cares. METHODS: In this study, charts of adult patients presenting to the dental department of a regional hospital in Trieste, Italy, from January 2018 and January 2019 were reviewed. Patients with complete files were retrieved, and those with orofacial pain complaints were excluded. OBC-21 scores and grades (score of 0 corresponding to no risk, 1-24 to low risk, and higher than 24 to high risk) were analyzed and stratified according to age and sex. RESULTS: Data from a total of 1424 patients were reported. The overall mean OBC score was 13.3 ± 9.9, with 6.7% no-risk grade, 79.6% low-risk grade, and 13.7% high-risk grade. In general, mean OBC scores decreased with increasing age. Females showed a higher frequency of high-risk grade than males. Most frequent prevalent habits included yawning (73.1%), eating between meals (66.9%) and chewing food on one side only (63.3%). Other behaviors were also highly prevalent, including pressing, touching, or holding teeth together other than while eating (52.7%) and awake clenching (47.5%). CONCLUSION: A low-risk grade of oral behaviors has been found to be frequent in our sample. Future studies are warranted to confirm these findings in larger, representative general populations and to assess if any of these habits are linked to negative effects on the stomatognathic system.

Artificial intelligence to support early diagnosis of temporomandibular disorders: A preliminary case study.

BACKGROUND: Temporomandibular disorders (TMDs) are disabling conditions with a negative impact on the quality of life. Their diagnosis is a complex and multi-factorial process that should be conducted by experienced professionals, and most TMDs remain often undetected. Increasing the awareness of un-experienced dentists and supporting the early TMD recognition may help reduce this gap. Artificial intelligence (AI) allowing both to process natural language and to manage large knowledge bases could support the diagnostic process. OBJECTIVE: In this work, we present the experience of an AI-based system for supporting non-expert dentists in early TMD recognition. METHODS: The system was based on commercially available AI services. The prototype development involved a preliminary domain analysis and relevant literature identification, the implementation of the core cognitive computing services, the web interface and preliminary testing. Performance evaluation included a retrospective review of seven available clinical cases, together with the involvement of expert professionals for usability testing. RESULTS: The system comprises one module providing possible diagnoses according to a list of symptoms, and a second one represented by a question and answer tool, based on natural language. We found that, even when using commercial services, the training guided by experts is a key factor and that, despite the generally positive feedback, the application's best target is untrained professionals. CONCLUSION: We provided a preliminary proof of concept of the feasibility of implementing an AI-based system aimed to support non-specialists in the early identification of TMDs, possibly allowing a faster and more frequent referral to second-level medical centres. Our results showed that AI is a useful tool to improve TMD detection by facilitating a primary diagnosis.

The Impact of Orthodontic Treatment on Masticatory Performance: A Literature Review.

The aim of this narrative review was to evaluate the possible association between orthodontic therapy and improved masticatory function. A search strategy was conducted using the PubMed database for up to January 2020 using the keywords "mastication" and "orthodontics". Only human studies investigating mastication in orthodontics settings were selected. The search strategy resulted in 1,011 articles, out of which 57 were included in the final analysis. Investigations have generally agreed that masticatory and chewing functions improved post-orthodontic and orthognathic treatments. Studies also showed improvement in the quality of life of patients' post-orthodontic treatment. The articles examined reinforced that besides esthetic reasons, orthodontic therapy does improve the masticatory and chewing functions of individuals, ultimately enhancing their health-related quality of life.

Circumpubertal maxillomandibular growth in untreated subjects with skeletal Class II relationship: A controlled longitudinal study according to the third finger middle phalanx maturation.

INTRODUCTION: Despite the substantial prevalence of skeletal Class II Division 1 malocclusion, only a few studies analyzed the maxillomandibular growth changes in these subjects with contrasting results. This study compared the longitudinal maxillomandibular growth changes in growing subjects with Class I and II skeletal relationships, specifically during the circumpubertal growth phase assessed by the modified third finger middle phalanx maturation (MPM) method. An attempt to uncover any maxillomandibular growth peak in subjects with Class II relationship has been followed. METHODS: From the files of the Burlington Growth Study, a total of 32 subjects (13 males, 19 females) with at least 7 annual lateral cephalograms taken at 9 and 16 years old were included and equally distributed between Class II and Class I groups matched for sex. Overall changes in 12 cephalometric parameters were calculated, and maxillomandibular growth peak was also identified individually and used to register subjects according to the year of growth peak ± 2 years. According to this procedure, annualized changes (trends) were analyzed along with the corresponding prepubertal, pubertal, and postpubertal MPM stages. RESULTS: No significant differences were seen between subjects with Class I and II skeletal relationships at 9 and 16 years, except for the parameters of the sagittal maxillomandibular relationship, such as ANB angle. Overall, changes for all the cephalometric parameters were similar between the groups, except for the CoGn distance increment that was significantly lower in the subjects with a Class II relationship. In both groups, the annual changes in CoA, CoGn, and CoGo distances showed a clear peak at the time point corresponding to a median MPM stage 3. CONCLUSIONS: In subjects with a skeletal Class II relationship, mandibular deficiency appears to be mostly established during the prepubertal growth stage and further aggravated during puberty. However, the maxillomandibular growth trend in subjects with Class II relationship is generally similar to that of subjects with a Class I relationship, including the existence of a pubertal peak.

Does the planned miniscrew position reflect the achieved one? A clinical study on the reliability of guided miniscrew insertion using lateral cephalogram and maxillary stereolithography file for planning.

INTRODUCTION: The anterior area of the palate is widely used as an insertion site for orthodontic miniscrews. These temporary anchorage devices can be placed either directly or using an insertion guide, and various kinds of digital planning and guides are currently available. This study aimed to verify if the guided procedure can guarantee the correct position of the miniscrews on the patient compared with the digital project. METHODS: Twenty-five consecutively treated patients were included in the study. Angular and linear displacements of the miniscrews were evaluated among 3 groups: the planned position, the model position, and the achieved position. RESULTS: The median achieved angle between 2 digitally planned screws was 6.22° (interquartile range: 4.35°, 9.08°) and the difference between the angles in the planning and the achievement groups was significant (P <0.001). Lateral and vertical differences were also found among the 3 groups. CONCLUSIONS: Results show that the examined workflow is clinically efficient. Differences between the digitally planned position of the orthodontic miniscrews, the control position, and the achieved position were detected both for angular and linear measurements but were not clinically significant.

Low Arousal Threshold Estimation Predicts Failure of Mandibular Advancement Devices in Obstructive Sleep Apnea Syndrome.

Introduction: The treatment of choice for obstructive sleep apnea syndrome (OSAS) is continuous positive airway pressure (CPAP). However, CPAP is usually poorly tolerated and mandibular advancement devices (MADs) are an alternative innovative therapeutic approach. Uncertainty still remains as to the most suitable candidates for MAD. Herein, it is hypothesized that the presence of low arousal threshold (low ArTH) could be predictive of MAD treatment failure. Methods: A total of 32 consecutive patients, with OSAS of any severity, who preferred an alternate therapy to CPAP, were treated with a tailored MAD aimed at obtaining 50% of their maximal mandibular advancement. Treatment response after 6 months of therapy was defined as AHI < 5 events per hour or a reduction of AHI ≥ 50% from baseline. Low ArTH was predicted based on the following polysomnography features, as previously shown by Edwards et al.: an AHI of 82.5% and a hypopnea fraction of total respiratory events of >58.3%. Results: There were 25 (78.1%) responders (p-value < 0.01) at 6 months. Thirteen patients (40.6%) in the non-severe group reached AHI lower than 5 events per hour. MAD treatment significantly reduced the median AHI in all patients from a median value of 22.5 to 6.5 (74.7% of reduction, p-value < 0.001). The mandibular advancement device reduced AHI, whatever the disease severity. A significant higher reduction of Delta AHI, after 6 months of treatment, was found for patients without low ArTH. Conclusions: Low ArTH at baseline was associated with a poorer response to MAD treatment and a lower AHI reduction at 6 months. A non-invasive assessment of Low ArTH can be performed through the Edwards' score, which could help to identify an endotype with a lower predicted response to oral appliances in a clinical setting.

Accuracy of the digital workflow for guided insertion of orthodontic palatal TADs: a step-by-step 3D analysis.

BACKGROUND: The introduction in the orthodontic field of the digital workflow for guided insertion of palatal TADs and the development of the 1-visit protocol led to the reduction of chair time and the possibility of complete customization of designs and materials. Conversely, the reduction of operative steps implicates a lower tolerance of deviations between the planned and the actual position of the miniscrews, particularly when the orthodontic device is fixed on 4 palatal TADs or has a rigid structure. This study aims to analyze the influence of each step of the digital workflow on the deviation of the miniscrews' axis of insertion in a bicortical sample. The null hypothesis is that there are no significant differences in the deviations among the operative steps. METHODS: 33 subjects were selected for insertion of bicortical palatal miniscrews with a 1-visit protocol. Digital files were collected at the three stages of the workflow (i.e., digital planning, laboratory prototype, post-insertion impression). A 3D software analysis was performed on a total of 64 miniscrews. After automatic shape recognition of the guiding holes of the digital plan and the scanbodies of the laboratory prototype and post-insertion impression as geometric cylinders, their three-dimensional longitudinal axis was traced and the deviation among them was calculated. Friedman test with Bonferroni correction was performed to assess the significance of the deviations among the three steps, with significance set at p < 0.05. RESULTS: The laboratory step has a significantly lower degree of deviations (2.12° ± 1.62) than both the clinical step (6.23° ± 3.75) and the total deviations (5.70° ± 3.42). No significant differences were found between miniscrews inserted on the left or the right side. CONCLUSIONS: This study suggests that laboratory procedures such as surgical guide production or rapid prototyping don't play a significant role in the degree of deviations between the planned and the positioned palatal TADs. Conversely, the clinical steps have a bigger influence and need to be carefully evaluated. Despite this difference, there is a cumulative effect of deviations that can lead to the failure of the 1-visit protocol.

Skeletal expansion using a miniscrew-assisted rapid palatal expansion in a 50-year-old patient.

This case report illustrates a nonsurgical treatment plan using a miniscrew-assisted rapid palatal expander (MARPE) in a 50-year-old patient with maxillary transverse deficiency. The MARPE appliance consisted of a conventional Hyrax expander anchored to 4 orthodontic miniscrews. The exact locations of the miniscrews were determined with virtual planning software. Cone-beam computed tomography (CBCT) scans were superimposed on the maxillary digital model, and 3-dimensional-printed surgical guides were used to accurately position the mini-implants. A slow expansion protocol was used, and the appliance was held in place during the entire treatment (almost 20 months). Pretreatment, postexpansion, and posttreatment CBCT scans show the parallel expansion obtained without dental torque compensation or bite opening. The posttreatment scan showed that a long period is required to complete the midpalatal suture mineralization. MARPE has proven effective in correcting transverse discrepancies, even in adults. However, posttreatment CBCT imaging showed incomplete ossification of the midpalatal suture, demonstrating that the retention period should be extended in some adult patients.

Mechanical Evaluation of the Stability of One or Two Miniscrews under Loading on Synthetic Bone.

The aim of the present study was to evaluate the primary stability of a two-miniscrew system inserted into a synthetic bone and to compare the system with the traditional one. Forty-five bi-layered polyurethane blocks were used to simulate maxillary cancellous and cortical bone densities. Samples were randomly assigned to three groups-one-miniscrew system (Group A, N = 23), two-miniscrew system (Group B, N = 22) and archwire-only (Group C, N = 10). A total of 67 new miniscrews were subdivided into Group A (23 singles) and Group B (22 couples). 30 mm of 19″ × 25″ archwires were tied to the miniscrew. The load was applied perpendicularly to the archwire. Maximum Load Value (MLV), Yield Load (YL) and Loosening Load (LL) were recorded for each group. The YL of Group B and C had a mean value respectively of 4.189 ± 0.390 N and 3.652 ± 0.064 N. The MLV of Group A, B and C had a mean value respectively of 1.871 ± 0.318N, of 4.843 ± 0.515 N and 4.150 ± 0.086 N. The LL of Group A and B had a mean value respectively of 1.871 ± 0.318 N and of 2.294 ± 0.333 N. A two- temporary anchorage device (TAD) system is on average stiffer than a one-TAD system under orthodontic loading.

Cervical vertebral maturation: Are postpubertal stages attained in all subjects?

INTRODUCTION: The cervical vertebral maturation (CVM) method comprises 6 stages reported to be prepubertal (1 and 2), pubertal (3 and 4) and postpubertal (5 and 6), and its use has been recommended for planning treatment timing in orthodontics. Reliable use of the method implies that pubertal stages have to mature into postpubertal as soon as the growth peak is terminated. The present study was aimed at determining whether postpubertal CVM stages 5 or 6 are attained in all subjects. METHODS: A total of 450 adult subjects (270 females and 180 males; mean age, 30.4 ± 27.3 years; range, 20-45 years) seeking orthodontic treatment and having a lateral head film were included in the study. Customized cephalometric analysis was used, and each recording was converted into an individual CVM code according to the concavities of the C2 to C4 and shapes of C3 and C4. The retrieved CVM codes, either falling within the reported norms (regular cases) or not (exception cases), were also converted into the CVM stages and a newly introduced CVM score (0-9) capable of defining intermediate stage. RESULTS: The most frequent CVM stage was 5, while the CVM stage 6 was attained in only one third of the sample. Up to about 11% of adult subjects showed the pubertal CVM stage 4. Irrespective of the CVM stage or CVM score, no significant differences were seen between the sexes or across ages. The C4 showed a rectangular vertical shape in only 16.4% of the cases. CONCLUSIONS: The percentage of adult population maintaining a pubertal CVM stage 4 is not high, but still relevant from a clinical standpoint. In light of this finding, planning treatment timing-based only on CVM appears not fully reliable.

Do Chlorhexidine and Probiotics Solutions Provoke Corrosion of Orthodontic Mini-implants? An In Vitro Study.

PURPOSE: The aim of this study was to explore the surface roughness and hardness of the implant head of orthodontic mini-implants made from different alloys before and after their in vitro exposure to agents for prevention of gingivitis, mucositis, and peri-implantitis: chlorhexidine and probiotics. MATERIALS AND METHODS: Three types of commercially available mini-implants were tested: 316 stainless steel, titanium Grade 5, and titanium Grade 23 (both Ti-6Al-4V alloys with the same atomic weight percentage of Ti, Al, and V, with the difference being in maximal reduction of O2 in Grade 23 to 0.13% of atomic weight). They were immersed in three experimental solutions: artificial saliva, saliva with probiotic bacteria Lactobacillus reuteri, and saliva with oral antiseptic chlorhexidine (CHX). Samples were immersed for 28 days, thermocycled, then stored in an incubator at 37°C. Surface roughness and microhardness on five samples of each of the three implant types were measured by atomic force microscopy and the Vickers method, respectively. RESULTS: Exposure of titanium implant Grade 5 to probiotics significantly increased roughness compared with other media (P < .005). Exposure to CHX significantly increased the roughness of steel implants (P < .05). Neither saliva, probiotic, nor CHX altered microhardness of titanium implants significantly. In steel implants, the exposure to CHX and probiotics decreased microhardness compared with unexposed implants (P < .031), but not in comparison to saliva. CONCLUSION: Probiotics seem to increase roughness of titanium mini-implants, while CHX seems to increase roughness of steel mini-implants. Only stainless steel implants had an altered, decreased hardness after exposure to CHX, although the same was found after their exposure to saliva. For patients undergoing orthodontic treatment with temporary anchorage units, CHX could be recommended for titanium, and probiotics for stainless steel mini-implants in oral-hygiene maintenance.

Class III Treatment with Skeletal and Dental Anchorage: A Review of Comparative Effects.

OBJECTIVES: This review addresses the comparative effects of skeletal anchored maxillary protraction (MP) versus dental anchored MP. MATERIALS AND METHODS: The studies retrieved had to have both test and control groups treated by the use of a facemask with or without the use of skeletal anchorage though either (palatal/buccal) maxillary or mandibular miniscrews/miniplates, respectively. RESULTS: Nine articles were included. Dentoalveolar changes were seen in all the studies. In particular, a significant proclination of the upper incisors was documented in the group treated with a dental anchorage facial mask, as compared to that treated with skeletal anchorage. Comparing the two methods, almost all the studies indicated a greater maxillary advancement in the group treated with skeletal anchorage. CONCLUSIONS: Therapies with skeletal anchorage produce greater maxillary protraction, reducing undesirable dental effects.

Cephalometric Floating Norms for the ß Angle and MMBP-Wits.

The importance of an accurate measurement of sagittal jaw relationship, that is, skeletal class, is critical to orthodontic treatment planning. The ANB angle, ß angle, and MMBP-Wits are among indices of sagittal jaw relationship. All of these indices are subjected to geometrical distortion, especially from facial divergence, making the use of floating (individualized) norms necessary. This study thus provides floating norms for the ANB angle and for the first time for the ß angle and MMBP-Wits. Lateral head films were obtained from 119 subjects (74 females and 45 males; mean age, 11.2 ± 1.5 years; range, 8.2-14.0 years) with well-balanced and pleasant profile and a near-ideal occlusion. Multiple regression models were employed to quantify the association of the ANB angle, ß angle, and MMBP-Wits each with other four angular cephalometric parameters including SNA, SN/PP, SN/MP, and NSBa angles. The ß angle and MMBP-Wits were associated with the SNA and SN/MP angles; the ANB angle was associated with all the four other cephalometric variables. Floating norms for the ß angle and MMBP-Wits (but not ANB angle) have been cross-tabulated according to the SNA angle (from 74° to 90°) and SN/MP angle (from 24° to 44°). While the ANB angle is subjected to significantly more geometrical distortion as compared to the ß angle and MMBP-Wits, floating norms may be used to individualize the reference values for both the ß angle and MMBP-Wits.