INTRODUCTION
The smile is one of the most important components of perception and self-perception of people. It directly influences the facial expression and physical attractiveness of individuals (1). In contemporary dental practice, patient-driven esthetic diagnosis and treatment planning force clinicians to focus on the smile zone, which is directly from the patient’s perspective(2). Improper anterior spacing can cause diastemas and thus it could be considered as unesthetic by lay people (3,4). It can be caused by microdontia, a genetic condition in which the teeth are abnormally small. This anomaly can be localized or generalized. One of the most common forms of localized microdontia is that which affects the maxillary lateral incisors, called a “peg lateral”. A peg-shaped incisor has a marked reduction in diameter, extending from the cervical region to the incisal edge (5).
The prevalence of peg-shaped upper lateral incisors was reported to be higher than the prevalence of other morphological variations of permanent teeth. Agenesis or size or shape anomalies of maxillary lateral incisors are quite common, with a prevalence of 1,6% to 4,9% and can be either unilaterally or bilaterally on the left or right side of the jaw with a higher incidence on the left side of the incisors (6). Yet, women have 1.35 more chance of having peg-shaped maxillary permanent lateral incisors when compared to men. Simultaneous presence of both upper lateral incisors is a rare case (7).
Treatment choices for lateral peg-shaped incisors are various, however for any esthetic rehabilitation, it is necessary to follow a medical framework respecting the tissue economy and combining the biological, functional, and esthetic imperatives which are inseparable.
Treatment options for peg shaped laterals could be: no treatment, orthodontic treatment first (to align the teeth in the arch), direct composite bonding onto peg laterals, indirect composite placement, bonded crowns or veneers, or even metal crowns (8), extractions and implant placement, or a combination of treatments.
Orthodontics is the first esthetic therapy in the gradient and the most conservative. Most of the time the patient presents a maxillary default : a dento-dental disharmony resulting in an anterior Bolton index greater than 77.2% +/- 0.22 (9). An ill-considered closure of the spaces would lead to anterior buttock. In addition to the esthetic appearance of the reconstructed laterals, the lateral teeth are then overhung, and a functional anterior guide is ensured after prior placement of the canines in Angle Class I. Several therapeutic solutions can be envisaged depending on the associated anomalies: extractions, closing of spaces with the consequences associated with dento-dental disharmony, or morphological rehabilitation of these teeth to ensure the establishment of ideal inter-archal relationships.
In this case, the definitive mesio-distal diameter and final vertical positioning of these teeth must be determined at the beginning of the ODF treatment. In order to facilitate active orthodontic treatment (both for the bonding of an attachment to this tooth and for its future pre-prosthetic design), the peg-shaped lateral incisor should be provisionally reconstructed according to the described esthetic criteria (shape, mesio-distal diameter, color in relation to the adjacent teeth) prior to the placement of any appliances. This provisional restoration can be improved and readjusted during orthodontic treatment. However, the intra- and/or inter-arch clinical situation does not always allow it in case of maxillary anterior crowding with overlaps, dental rotation, linguo-version of the incisal block reducing the arch perimeter and consequently the spaces devoted to the lateral riziform incisor. The orthodontic treatment will, under these conditions, have to start aligning and levelling the maxillary arch, in particular, in order to meet the above-mentioned requirement.
The lack of clear best practices in the scientific literature encouraged us to establish a protocol to facilitate the therapeutic decision with the general practitioner, the orthodontist and the patient, and ultimately to guarantee the therapeutic solution best suited to the clinical situation. The patient is often referred to the general practitioner once the orthodontic treatment has been completed. This lack of coordination between disciplines represents a real loss of opportunity for patients. In this article we aim to clearly establish the different considerations to be evaluated and the steps to follow, once orthodontic treatment is started, to ensure best possible rehabilitation for the patient.