ObjectiveThe aim of the study was to analyze the prevalence and distribution of ectopic eruption of the permanent maxillary first molar (EEM) in individuals scheduled for orthodontic treatment and to investigate the association of EEM with dental characteristics, maxillary skeletal features, crowding, and other dental anomalies.MethodsA total of 1,317 individuals were included and randomly divided into two groups. The first 265 subjects were included as controls, while the remaining 1,052 subjects included the sample from which the final experimental EEM group was derived. The mesiodistal (M-D) crown width of the deciduous maxillary second molar and permanent maxillary first molar, maxillary arch length (A-PML), maxillomandibular transverse skeletal relationships (anterior and posterior transverse interarch discrepancies, ATID and PTID), maxillary and mandibular tooth crowding, and the presence of dental anomalies were recorded for each subject, and the statistical significance of differences in these parameters between the EEM and control groups was determined using independent sample t-tests. Chi-square tests were used to compare the prevalence of other dental anomalies between the two groups.ResultsThe prevalence of maxillary EEM was 2.5%. The M-D crown widths, ATID and PTID, and tooth crowding were significantly greater, while A-PML was significantly smaller, in the EEM group than in the control group. Only two subjects showed an association between EEM and maxillary lateral incisor anomalies, which included agenesis in one and microdontia in the other.ConclusionsEEM may be a risk factor for maxillary arch constriction and severe tooth crowding.

The aim of the study was to analyse the prevalence and distribution of buccally displaced canines (BDCs) in subjects scheduled for orthodontic treatment and to investigate the association between BDC and sagittal, vertical, and transverse dentoskeletal relationships. A study sample of 1852 subjects was examined, and it was divided randomly into two groups. A first group of 252 subjects served as control group: the 'reference' prevalence rates for the examined parameters were calculated in this group. The remaining 1600 subjects comprised the sample from which the experimental BDC group was derived. Presence of unilateral or bilateral maxillary BDC, ANB, and SN GOGn angles for sagittal and vertical skeletal relationships, intercanine and intermolar distances, and tooth crowding at the maxillary arch were recorded for each subject. The statistical significance of differences between the BDC and the control groups in transverse relations and tooth crowding at the upper arch was tested by means of independent sample t-tests. Chi-square tests were performed to compare the prevalence rates of BDC and also sagittal and vertical skeletal features in the two groups. The prevalence rate of BDC was 3.06 per cent with a male-to-female ratio of 1:1. BDC subjects exhibited a significant association with hyperdivergent skeletal relationships (38.8%), reduced maxillary intercanine width, and crowding in the upper arch. The presence of specific dentoskeletal characteristics can be considered as a risk indicator for developing a buccal displacement of upper permanent canines.

obiettivi. Scopo del lavoro è illustrare le più recenti strategie di trattamento intercettivo in una fase di dentizione mista precoce nei pazienti con malposizione del canino permanente mascellare. Materiali e metodi. Dopo aver eseguito la diagnosi di dislocamento del canino è possibile attuare una serie di manovre di terapia intercettiva per favorire la sua eruzione. Sono descritte singolarmente tutte le metodiche di trattamento proposte dalla letteratura, specificando per ogni opzione l’apporto e la validità scientifica. Risultati. Da un’attenta analisi e revisione bibliografica emerge come l’approccio terapeutico nei confronti di una malposizione canina abbia subito un’importante evoluzione nel corso degli anni. Si passa infatti da un metodo di tipo passivo/ osservazionale, che prevede la semplice estrazione del canino deciduo e il monitoraggio radiografico, a interventi di terapia attiva più complessi che possono prevedere l’espansione del mascellare superiore, in associazione o meno alla distalizzazione dei settori latero-posteriori. Discussione. Nei casi di diagnosi precoce, il recupero del canino malposto prevede un nuovo approccio che integra le manovre già descritte con l’estrazione del canino e del primo molare decidui come elementi determinanti nella programmazione ortodontica. Conclusioni. L’obiettivo del trattamento intercettivo del canino mascellare è quello di aumentare le percentuali di successo di eruzione spontanea del canino permanente mascellare diagnosticato in una fase precoce di sviluppo, evitando meccaniche ortodontiche più complesse e biologicamente invasive per il paziente