Are palatal rugae reliable markers for 3D superimposition and forensic human identification after palatal expansion? A systematic review.

OBJECTIVES: Palatal rugae are periodic structures situated in the palatal mucosa, often used as landmarks for human identification and superimposition of digital dental models. This review aims to collect the current evidence regarding whether orthodontic palatal expansion could affect the stability of the palatal rugae and to give preliminary guidelines. MATERIALS AND METHODS: A systematic review of the literature was performed in the scientific databases Pubmed; Embase; WoS; and Cochrane. Grey Literature was also sought (clinicaltrial.gov; ICTRP; AHRQ; INAHTA). The search protocol, was registered in PROSPERO (N*208722). Data extraction comprised: year of publication, journal, sample size, characteristics of the experimental and control group, type of expander, expansion protocol, rugae classification, measurement method on casts, time between casts, method error, rugae change, morphology change and overall outcome. Risk of bias of the included articles was evaluated with the Newcastle-Ottawa Scale. RESULTS: A total of 12394 manuscripts were retrieved after duplicate removal. From these, nine articles were finally included for data extraction. three studies scored as low risk of bias, two as medium and four as high. CONCLUSIONS: The morphology of the palatal rugae can be modified by palatal expansion techniques, especially by rapid maxillary expansion. The first rugae is the most stable along with the points close to the palatal midline, which should be used as a reference both for manual or semi-automatic superimpositions. Human identification and serial superimpositions based on palatal rugae should not be carried immediately post expansion and be taken in consideration with caution in patients who underwent prior palatal expansion.

Risk factors for orthodontic fixed retention failure: A retrospective controlled study.

Objective: : To investigate the potential correlation between fixed orthodontic retention failure and several patient- and treatment-related factors. Methods: : Patients finishing treatment with fixed appliances between 2016 and 2017 were retrospectively included in this study. Those not showing fixed retention failure were considered as control group. Patients with fixed retention failure were considered as the experimental group. Additionally, patients with failure of fixed retainers in the period of June 2019 to March 2021 were prospectively identified and included in the experimental group. The location of the first retention failure, sex, pretreatment dental occlusion, facial characteristics, posttreatment dental occlusion, treatment approach and presence of oral habits were compared between groups before and after treatment separately by using a Fisher exact test and a Mann-Whitney U test. Results: : 206 patients with fixed retention failure were included, 169 in the mandibular and 74 in the maxillary jaws. Significant correlations were observed between retention failure in the mandibular jaws and mandibular arch length discrepancy (P = 0.010), post-treatment growth pattern (P = 0.041), nail biting (P < 0.001) and abnormal tongue function (P = 0.002). Retention failure in the maxillary jaws was more frequent in patients with IPR in the mandibular jaws (P = 0.005) and abnormal tongue function (P = 0.021). Conclusions: : This study suggests a correlation between fixed retention failure and parafunctional habits, such as nail biting and abnormal tongue function. Prospective studies with larger study populations could further confirm these results.

Performance of the Malmgren Index for Assessing Root Resorption on 2D vs. 3D Radiographs: A Pilot Study.

OBJECTIVES: To compare the performance of the Malmgren index on 2D and 3D radiographs. METHODS: Patients with a panoramic radiograph and a cone beam computed tomography (CBCT) taken at an interval of <3 months and presenting root resorption (RR) on at least one incisor and/or canine were retrospectively included. RR was scored twice by two observers using the Malmgren index in both the 2D and 3D sets, and intra-class correlation coefficient (ICC) was calculated. RESULTS: 155 teeth were analyzed. The ICC was the lowest in 2D, followed by overall, transversal and sagittal 3D. Malmgren scores were systematically higher in 2D, which overestimated RR, especially in the transversal plane on all incisors and canines and in the sagittal plane on the maxillary incisors. 2D respectively leads to 28.0-34.8% of false positives and negatives when discriminating between RR or not. The early stages of RR are often misdiagnosed in 2D, while later stages are more accurate. CONCLUSIONS: The original Malmgren index is not suited for 3D images, especially axial, where using dichotomized values (resorption yes/no) leads to overestimation of RR. A low-dose CBCT of the upper incisors could detect RR with high diagnostic accuracy in the early stages of orthodontic treatment, especially in patients with dental trauma or familial RR history.

Early prevention of maxillary canine impaction: a randomized clinical trial.

OBJECTIVES: To investigate the effect of three interceptive measures (slow maxillary expansion (SME) with removable plates (1), extraction of both upper deciduous canines (DC) (2) and no intervention (3)) on maxillary canine (MC) position in patients with early mixed dentition (EMD) and lack of upper arch space. These three groups were additionally compared to a control group (4) with adequate upper arch space. NULL HYPOTHESIS: None of the studied strategies outperforms the others regarding improvement of MC position. TRIAL DESIGN: Four-arm parallel group prospective randomized controlled trial. PARTICIPANTS: Patients in EMD with at least one impacted MC, non-resorbed DC, and no crossbite. INTERVENTIONS: Patients with a lack of space were randomly distributed to protocols (1), (2), and (3). PRIMARY OBJECTIVE: To assess the change in MC position after 18 months follow up. SECONDARY OBJECTIVES: To assess canine eruption and need for orthodontic intervention within 18-60 month follow up. OUTCOME ASSESSMENT: Five variables defined canine position: sector, canine-to-midline angle, canine-to-first-premolar angle, canine-cusp-to-midline distance, and canine-cusp-to-occlusal-plane distance on two panoramic radiographs at 0 (T1) and 18 months (T2). Mean differences between groups were compared with linear mixed models, corrected for age and sex. RANDOMIZATION: The patient allocation sequence was generated by an electronic randomization list. BLINDING: The operator taking the measurements was blinded to the groups. RESULTS: Seventy-six patients were included (142 canines, mean age 9.2 years, 60.5 per cent male, mean follow up 1.9 years), 19, 17, 14, and 26 patients in groups 1-4, respectively. In absence of dental crossbite in patients with lack of space and impacted MC, SME improved the canine sector (P = 0.040), compared to no intervention (P = 0.028). Canine-to-midline angle and canine-to-occlusal-plane distance significantly decreased in all groups at T2. Extraction improved the canine-to-first-premolar angle at T2 more than other strategies in EMD (P = 0.015-0.000). CONCLUSIONS: Early SME improves the canine sector and reduces the need for major orthodontic intervention in the long term. Taking a first panoramic radiograph in EMD allows timely intervention in case of MC impaction. TRIAL REGISTRATION NUMBER: NCT05629312 (Clinical Trials.org). Trial status: follow up ongoing.

Third molar position after completion of orthodontic treatment: a prospective follow-up.

OBJECTIVES: To prospectively follow up a previously reported sample, analyzing (1) changes in third molar (M3) position after completion of 2 different types of orthodontic treatment: (2) non-extraction treatment with (HG) vs without cervical headgear (non-HG) and (3) first or second premolar extractions (PM1-2) compared to a non-extraction group (NE). METHODS: A total of 474 patients were prospectively followed up. Panoramic radiographs were taken pre- (T1), post-treatment (T2) and at follow-up (T3). T3 records (a mean of three years after treatment) were available for 135 (HG vs non-HG) and 134 patients (PM1-2 vs NE), respectively. Angulation, vertical position, relation with the mandibular canal and mineralization status of M3 at T2 and T3 were statistically compared. RESULTS: The HG group presented more M3 with ideal vertical orientation at T3. In NE-cases, further improvement in angulation and orientation can be expected after debonding, as well as a deterioration in the relationship with the mandibular canal. Extractions accelerated upper M3 vertical eruption and PM2 extractions led to long-term larger lower retromolar spaces. CONCLUSIONS: The use of cervical headgear increased upper M3 uprighting three years after debonding, while little changes in M3 position were found after orthodontic treatment with extractions. However, PM2 extractions led to larger retromolar spaces and better M3 angulation in the long term.

Influence of age and diet consistency on the oral muscle pressure of orthodontically treated and untreated subjects with normal occlusion and comparison of their 3D facial shape.

OBJECTIVES: (1) To investigate the effect of age and diet consistency on maximum lips, tongue and cheek pressure of orthodontically treated and untreated subjects with normal, Class I dental occlusion, (2) to find out whether there is a muscle imbalance between anterior tongue and lip pressure in the same subjects at different ages and (3) to compare the 3D facial shape of treated and untreated individuals. MATERIAL AND METHODS: Subjects with normal occlusion were prospectively grouped into orthodontically treated/untreated and in children/adolescents/adults. Iowa Oral Performance Instrument was used to record the maximum muscle pressure. Two-way ANOVA and Tukey post hoc test analysed age-specific differences in muscle pressure. Two-way ANCOVA analysed the effect of diet consistency on muscle pressure. Lips and tongue imbalance was analysed using z-scores and 3D faces using a generalized Procrustes analysis. RESULTS: One hundred thirty-five orthodontically untreated and 114 treated participants were included. Muscle pressure was found to increase with age in both groups, except for the tongue in treated subjects. No differences in the balance between lips and tongue muscle pressure were found, but a higher cheek pressure in untreated adults (p<0.05) was observed. 3D facial shapes showed subtle differences. Untreated subjects with soft diet consistency showed lower lip pressure (p<0.05). CONCLUSION: Oral muscle pressure of orthodontically treated patients without relapse does not differ from that of untreated patients with Class-I occlusion. CLINICAL RELEVANCE: This study provides normative lip, tongue and cheek muscle pressure in subjects with normal occlusion, which can be used for diagnosis, treatment planning and stability.

The use of blended learning in postgraduate education in orthodontics: student versus teacher perception.

OBJECTIVE: To investigate the use of blended learning (BL) in Postgraduate Education in Orthodontics. METHODS: A self-developed online questionnaire was sent to 244 teaching staff members of the European Orthodontic Departments. They were asked to answer it and share it with their postgraduate students. 18 questions for teaching staff and 27 for postgraduate students evaluated the use, perceptions, feedback options, learning outcomes, and teacher's role in BL. The answers of teaching staff and students were statistically compared by Fisher's Exact Test, Chi-Square Test, Unpaired t-test, and Mann-Whitney Test. RESULTS: 124 completed questionnaires were received, 44 from teaching staff and 80 from postgraduate students. Teaching staff is more acquainted with BL than students (P = 0.001). Both groups found BL courses a good alternative to traditional courses (P = 0.654). The use of interactive multimedia was more appreciated by students (P = 0.015). Both groups found students' results not to change with BL, but teaching staff had a more negative perception (P = 0.012). In general, teaching staff perceived feedback and interaction as less essential than postgraduates in BL. Teaching staff felt more like coaches when using BL, while postgraduates did not perceive any changes in teachers' roles (P = 0.006). Limitations: Due to the General Data Protection Regulation it was not possible to directly contact the postgraduate students in Postgraduate Orthodontic Programs throughout Europe. Therefore, this study completely relied on the goodwill of the teaching staff being contacted. CONCLUSION: The main differences in perception between teaching staff and postgraduate students were student results, teachers' role, use, and importance of feedback and interactive multimedia. Although both groups found BL courses to stimulate students' learning and to be a relevant cost-effective addition to traditional courses, they were hesitant to fully replace them with BL.

Skeletal and soft-tissue changes in humans with untreated normal occlusion throughout lifetime: a systematic review.

Age-related skeletal and soft-tissue changes are important in orthodontics, especially due to the increase of adult patients seeking treatment. The aim of this study is to assess the available evidence regarding age-related skeletal and soft-tissue changes in untreated Angle Class I. Articles studying skeletal and soft-tissue changes in orthodontically untreated subjects with Angle Class I and comparing them between age groups were included. Studies focusing on a single age group or in languages other than English were excluded. Risk of bias was assessed with both the MINORS and ROBINS-I tools. 50 studies were included, showing high methodological heterogeneity and a lack of information in subjects over 60 years old. In subjects with Angle Class I, the mandibular plane inclination was reported to reduce from 7 and 20 years old, while the anterior and posterior facial height continue to increase in late adult life. The anterior cranial base length increases until 20 years old, afterwards decreasing slowly until late adulthood. Nasal width increases and the nasolabial angle decreases during adolescence. Upper lip length and lower lip length increase from 6 to 18 years along with retrusion of the lips in late adulthood. Age-related skeletal and soft-tissue changes are documented in the literature from childhood until the fifth decade of life, but studies mostly focus on subjects until 20 years old. Changes after the second decade of life are studied only for the vertical and sagittal dimensions. No changes are reported in the transversal dimension beyond 15 years for neither skeletal nor soft tissues. Well-designed, long-term prospective cohort studies considering all three dimensions of skeletal and soft tissues are needed for confirmation of these findings (PROSPERO: CRD42020203206).

Age- and sex-related differences in 3D facial shape and muscle pressure in subjects with normal occlusion.

BACKGROUND AND OBJECTIVE(S): (1) To derive descriptive statistics of three-dimensional (3D) facial shape, lip and cheek muscle pressure in subjects of European descent with normal dental occlusion. (2) To analyse the effect of age and sex on 3D-facial soft tissue morphology and muscle pressure in the same sample. (3) To assess the independent effect of muscle pressure on face shape. METHOD: 129 subjects with normal occlusion were cross-sectionally recruited and divided into: children (mixed dentition), adolescents and adults (permanent dentition, < and ≥18 years respectively). Muscle pressure was recorded using the Iowa Oral Performance Instrument. MeshLab, MeVisLab and Meshmonk tool box were used to clean, annotate landmarks and generate the 3D images. Two-way analysis of variance and post-hoc tests were used to analyse age and sex differences in face shape and muscle pressure. The effect of muscle pressure on face shape was analysed by Pearson correlation and Partial Least Square regression. RESULTS: Significant facial differences were observed between adults and adolescents and adults and children in both sexes, showing flattening of cheeks and lips and protrusion of nose and chin. Significant cheek protrusion and retrusion of the vertical midface were found in adult women compared to men. Lip and cheek pressure increased with age, but their effect on face shape was not significant. CONCLUSIONS: This study provides 3D age- and sex-specific facial models and muscle pressure of subjects without malocclusion. These can be used as a reference for clinicians focused on facial assessment in treatment planning and follow-up.

Neuromuscular Stability of Dental Occlusion in Patients Treated with Aligners and Fixed Orthodontic Appliance: A Preliminary Electromyographical Longitudinal Case-Control Study.

The aim of the present study was to evaluate if, after treatment with aligners (ALIGN) and fixed orthodontic appliance (FOA), alterations of the neuromuscular activity may occur and if differences in these changes can be detected between the two treatments. Sixteen healthy patients (7 FOA, 9 ALIGN) with class I or class II molar relation were recruited. Standardized surface electromyography (ssEMG) was used to evaluate the activity of the masticatory muscles (masseters-MM and temporalis-TM) before the beginning of the orthodontic treatment (T1), at the end (T2), and 3 months (T3) after the end of the treatment. Intragroup (within timepoints) and intergroup differences were statistically analyzed. At T1, the mean values of each ssEMG index were within the normal range in both groups. At T2, the FOA group showed larger differential recruitment of the MM than TA muscles with a value slightly over the normal range. All the indexes were normalized at T3, and no differences emerged between groups. In the FOA group, the index of MM symmetrical contraction increased significantly at T3 compared to T1 and T2. In the ALIGN group, no significant changes were observed between each timepoint. In FOA subjects, a slight alteration of the muscular activity appeared immediately after bracket removal and this alteration normalized after 3 months of rescue. In subjects treated with aligners, no significant alteration of the muscular activity was assessed.

Evolution of root length throughout orthodontic treatment in maxillary incisors with previous history of dental trauma: a longitudinal controlled trial.

OBJECTIVES: To compare changes in root length of maxillary incisors with and without dental trauma throughout orthodontic treatment. MATERIALS AND METHOD: Patients younger than 18 years, with trauma on at least one maxillary incisor, undergoing orthodontic treatment between 2017 and 2021 were included, using the contralateral side as control without trauma when available. Periapical radiographs were taken pre-treatment and at 6 months intervals, and root/crown ratio was calculated. Linear mixed models were used to describe the evolution of root length at the different time points and to compare trauma and control values. Differences between central and lateral incisors and between treatment modalities were additionally explored. RESULTS: A total of 1768 measurements were performed on 499 teeth (201 with trauma) in 135 patients. Incisor root length significantly decreased during orthodontic treatment in teeth with and without trauma. Lateral incisors with trauma were more susceptible to root resorption than those without trauma and central incisors. No significant decrease in root length was observed with removable appliances, which never exceeded 15 months of treatment. Treatment with fixed appliances led to gradually increasing, significant root length shortening in teeth with and without trauma. CONCLUSION: Treatment duration directly correlated with root length shortening both in teeth with and without trauma history. Teeth with trauma showed significantly more root resorption after treatment with fixed appliances while removable appliances had no significant influence on root length. CLINICAL RELEVANCE: Previous history of dental trauma is no absolute contra-indication to start orthodontic treatment, as long as treatment duration is kept as short as possible.

Dental changes in humans with untreated normal occlusion throughout lifetime: A systematic scoping review.

INTRODUCTION: Understanding age-related changes in normal dental occlusion is crucial for orthodontic treatment, planning, and retention, especially considering the increasing demand from adult patients. This review aimed to systematically perform a scoping literature review regarding age-related dental changes in untreated normal occlusion subjects. METHODS: An electronic search was performed until May 2020 using the following terms: "Dental Occlusion," "Dentition," "Ageing," and "Age groups." Articles studying changes in dental occlusal traits in orthodontically untreated subjects with neutroclusion and comparing them between various age groups were included. Studies focusing on a single age group or written in languages other than English were excluded. The risk of bias of the studies was assessed with both the methodological index for nonrandomized studies and the risk of bias in nonrandomized studies of intervention tools. RESULTS: From the initial 7681 articles, 40 were included. High methodologic heterogeneity was found among studies. Intercanine width was found to increase until 8.0 years and 15.0 years in the mandible and maxilla, respectively, whereas intermolar width increases in both arches until 26.0 years. After that, both parameters decrease into late adulthood. Crowding increases from mixed dentition until 60.0 years of age, especially in the mandible and females. Maxillary incisors procline with age while mandibular incisors retroclined. CONCLUSIONS: The age-related evolution of occlusal traits, together with skeletal and soft tissue changes, should be considered during orthodontic planning. Well-designed prospective cohort studies are necessary for confirmatory evidence. Expectations for treatment stability should consider muscular balance and inform patients that crowding is a sign of aging that should not always be seen as a failure of orthodontic therapy. Protocol registration number: PROSPERO CRD42020138846.

Self-Esteem and Oral Health-Related Quality of Life within a Cleft Lip and/or Palate Population: A Prospective Cohort Study.

(1) Objective: To investigate the oral health-related quality of life (OHRQoL) and self-esteem (SE) of a population with cleft lip and/or palate (CLP) and to compare it with a non-affected control cohort. (2) Materials and methods: This study comprised 91 CLP patients and a control group of 790 individuals, seeking orthodontic treatment. OHRQoL and SE were assessed by the Child's Perception Questionnaire (CPQ) and the Dutch adaptation of the Harter's Self-Perception Profile for Adolescents. Treatment need and self-perception of oral aesthetic were assessed using the Index of Orthodontic Treatment Need (IOTN) and the Oral Aesthetic Subjective Impact Scale (OASIS). Patients' expectations and motivation for treatment were also scored. Linear models were used for statistical comparisons between groups. (3) Results: The cleft group scored higher in all domains of the CPQ, OASIS, IOTN and regarding SE for the domains of scholastic competence, athletic competence, physical appearance and behavioral conduct. The cleft group was not only more motivated and expected less discomfort during treatment but also had higher expectations for the treatment outcome. (4) Conclusions: The OHRQoL of CLP patients is strongly correlated with the presence of an oral cleft, while SE remains a personal resource not influenced by the malocclusion or medical condition.

Dental development in patients with and without unilateral cleft lip and palate (UCLP): a case control study.

OBJECTIVE: To evaluate if the presence of unilateral cleft lip and palate (UCLP) causes delay in dental age and tooth development. MATERIALS AND METHODS: Panoramic radiographs of 189 non-syndromic UCLP patients, aged from 6 to 20 years, were collected. Two measures of tooth development were examined: dental maturity scale for the seven left mandibular teeth (dental age-DA) and the degree of each tooth development (developmental score-DS). All the teeth except third molars were staged according to the Demirjian's method. The data of the cleft group were compared with a control group matched for age and gender, based on the findings observed in other 189 panoramic radiographs. RESULTS: At all ages, DA was lower in the UCLP group, but not always significantly; the highest difference was - 1.411 for females at 13 years old and - 0.776 for males at 12 years old. DS of all teeth was significantly lower in the UCLP group, at all ages under 17 in females, and at all ages under 18 in males. In UCLP group, tooth development was more delayed in the maxilla compared with the mandible. No evidence of a slower development at the cleft side compared with the non-cleft side was highlighted. CONCLUSIONS: Significant lower dental development was observed in UCLP patients compared with control ones by using DS and DA indexes. CLINICAL RELEVANCE: These findings can help the clinicians in establishing a proper orthodontic and surgical diagnosis and treatment planning in UCLP patients and for forensic age estimation's purposes.

Electromyographic analysis of the oral phase of swallowing in subjects with and without atypical swallowing: A case-control study.

BACKGROUND: Swallowing is a complex physiologic function developing mostly in the first years of life. After 6 years old, if mature deglutition is not achieved, swallowing persists as "atypical swallowing" (AS). OBJECTIVE: The aim of this study was to detect any electromyographical differences in the muscular activation pattern in patients with and without AS. MATERIALS AND METHODS: 38 adolescents and young adults were selected for this study: 20 with atypical swallowing (AS group) and 18 without (C group). Standardised surface electromyographic analysis was performed by the same operator to detect the activity of masseter (MM), temporalis (TA) and submental (SM) muscles. A Student t test for unpaired data was carried out to detect differences between the AS and C groups. A 1-way ANOVA was performed to detect any differences between the three couples of muscles. RESULTS: When compared to controls, AS patients showed a significantly longer duration of activity for each couple of muscles and for the whole duration of swallowing act (P < 0.0001) as well as lower intensity of the SM activity (P < 0.05) than controls. Within the AS and C groups, masticatory muscles (MM and TA) showed lower duration of activation (P < 0.01) and lower intensity of the spike (P < 0.0001) than SM. Within the C group, masticatory muscles also reached their activation spike earlier (1-way ANOVA, P < 0.01) than SM. CONCLUSION: Two different muscular performance models have been defined: patients with AS showed a longer activity of all the muscles involved with a lower intensity of SM activity than that of controls.