Maxillary lateral incisor agenesis- case report for clinical management

The following case-report represents the trouble and treatment management of a young patient with a congenitally missing upper lateral incisor. MLIA (Maxillary Lateral Incisor Agenesis) is a state that affects dental aesthetics as well as function. After an interdisciplinary evaluation for the proper treatment plan, whether it should be treated by orthodontic space closure or by space opening and implantation, the treatment option of orthodontic space opening followed by insertion of Bicon® short implants was chosen. With this manageable treatment protocol and a minimum of sections for all involved parties, the individual optimum that satisfied the needs of the patient as best as possible was achieved. Introduction Hypodontia, the absence of at least one tooth, is the most common dental anomaly reported in humans [1] with a wide range of prevalence values reported in the permanent dentition ranging between 3.4– 10.1% in prevalence studies including white populations [2]. After the wisdom teeth and second premolars in the lower jaw, the upper lateral incisors are the third most frequently missing teeth with a prevalence of 1-2% [3]. Bilaterally cases are more common than unilaterally ones [4]. Unilateral agenesis is often associated with microdontia of the corresponding contralateral tooth, which in turn requires higher biomechanical claims in orthodontic therapy or often leads to extraction of the hypoplastic tooth to prevent any asymmetric effects as well as a midline shift. However, the exact etiology of congenital missing teeth is still controversial. Furthermore females have a slightly higher frequency as males [5]. Phylogenetic reduction of human dentition, heredity as well as developmental disorders and exogenous influences can represent possible reasons, as well as the significant familial aggregation of MLIA (Maxillary Lateral Incisor Agenesis) [6]. In this context, it was proven that the relative risk for a first-degree relative of an individual with MLIA to have the same type of agenesis was 15 times higher when compared with a relative of an individual without that agenesis [7]. MLIA represents a clinical problem impairing dental aesthetics as well as function from a very young age. The latter can be seen in the importance of the lateral incisors as a guide in the normal eruption of the permanent canine, absent upper lateral incisors may lead to canine impaction [8]. A significant correlation between canine displacement and tooth agenesis was demonstrated in a recent study, genetic association as well as the lack of canine guidance can give an explanation of canine displacement in the presence of agenesis of the maxillary lateral incisor [9]. The persistence of a primary lateral incisor in the arch beyond the expected time of eruption of its successor often suggests the agenesis. The definitive diagnosis requires a mandatory X-ray examination in order to confirm the assumed diagnosis. After clinical and radiological proof, a decision regarding the treatment options must be made, whether it should be treated by orthodontic space closure or by space opening and implantation [10]. Individual evaluation of the treatment choices requires a multidisciplinary approach to achieve the best possible result for the patient [11]. The treatment depends on a number of factors such as facial, occlusal, functional and periodontal features, as well as individual long-term stability [12]. Each of the available means of rehabilitation has its own advantages, disadvantages, indications and limitations. In orthodontic space opening followed by dental implantation, the number of teeth can be completed and the patient’s canine guidance remains preserved, even a neutral occlusion can be adjusted. Furthermore, the risk of midline shift, which can occur in unilateral MLIA, as well as the risk of occurrence of moderate to severe resorption which is even greater given in lateral incisors after orthodontic treatment can be prevented [13]. Recent literature has demonstrated high success as well as great survival rates of placing short implants [14,15]. In those cases in which space opening is indicated due to occlusion or skeletal pattern, Bicon® short implants can produce superior aesthetics especially in maxillary anterior restorations as well as long-term results. A study regarding the survival rate of short implants (6x5.7mm) and crestal bone level maintenance demonstrated a 100% 5-years-survival rate and a crestal bone level maintenance similar to conventional used implants (>8 mm) [15]. Likewise, when compared to implants of greater length, Gentile et al. could not find any difference in the short implant survival rate. Shorter implants can reduce a patient’s treatment time and discomfort as well as the costs related to possible graft procedures [16]. The patients that are presented in the following passages represent Correspondence to: Sarah Bär, Fetscherstr. 74, Haus 28, D-01307 Dresden, Germany, Tel: +49-(0)351-4584481; Fax: +49-(0)351-4585318; E-mail: [email protected]