Post-orthodontic restorative approach for young patients with missing anterior teeth: no-prep and ultraconservative techniques

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Keywords: Conservative restorations, Orthodontic space maintenance/opening, Recontouring.

Introduction

The early loss of permanent teeth following trauma or congenital aplasia may be corrected by orthodontic or prosthetic-implant means. The proper diagnosis of dental and skeletal conditions normally guides the choice between both treatment options (1, 2). The need for long term maintenance of prosthetic rehabilitations and their potentially negative influence on periodontal health (3) has always been considered as a main shortcoming favoring the orthodontic solution (4, 5). However, different anatomical, functional and esthetic anomalies may result from the orthodontic approach. The increasing concern of our patients for esthetics obliged restorative dentists to consider these deficiencies and to propose appropriate solutions. Well known treatment modalities such as bleachings and composite resin bonding have gained popularity as they improved in practicability, efficiency and predictability (6-8).

The aim of the present paper is to review and outline the interest of direct restorative modalities aimed to correct functional, anatomical and esthetic anomalies in patients with missing anterior teeth after orthodontics. The implication of this current therapeutic means in a comprehensive treatment planning will be discussed.

Treatment decision rationale

There are different decisional levels for the treatment of young patients with missing anterior teeth (Table 1). Each of them should be carefully weighted during treatment planning as both orthodontic or prosthodontic treatment options are in principle irreversible.

Essentials of orthodontic treatment strategy

Initial skeletal conditions as well as inter-arch and intra-arch dental relationships will determine the opportunity of an orthodontic space closure. In the absence of malocclusion evidence requiring mandibular tooth extractions, Class I occlusion cases usually favors treatment of the edentulous sector(s) by space maintenance or opening, followed by prosthetic replacement of the missing unit(s). Conversely, the presence of Class III malocclusion contraindicates orthodontic space closure of upper missing anterior teeth. Upper anterior spaces should be closed orthodontically in Class I extraction cases (severe crowding) or in some Class II cases where alveolar and skeletal growth potential preclude an orthodontic correction of the Class II relationship. It should be stressed that in any clinical situation, a diagnostic set-up is mandatory to anticipate the influence of the orthodontic treatment on occlusion, periodontal and dental conditions.

Figure 1 depicts the most common clinical problems and their possible restorative solutions, as following orthodontic space closure.

Space maintenance or opening

Depending on the occlusion conditions and particularly on the patient’s age at the moment of treatment planning, the alternative option to orthodontic space closure will be the space maintenance or opening, followed by prosthetic replacement of the missing teeth.

The three major treatment options for anterior tooth replacement are implant supported crowns, metal based of full ceramic adhesive bridges (rarely indicated in this context). Removable dentures are mostly considered for provisonalization, especially in young patients when definitive treatment has to be postponed. Since implants will not follow alveolar bone growth, fixture placement should not be used in young patients until full jaw growth is attained, from 18-20 years and even further (9, 10).

Ultraconservative restorative procedures after space closure option

The anatomical and esthetic anomalies that result from spontaneous space closure or following orthodontic procedures may be corrected by choosing the appropriate restorative modalities, including often a multidisciplinary approach (2).

Recontouring

Recontouring or enameloplasty may be performed during or following orthodontic treatment. For instance, when cuspids have to be moved in position of the lateral incisors, there is usually a space discrepancy. In this situation, the careful reduction of cuspid diameter will improve interarch relationship as well as reconstructive procedures (Fig. 4a, 4b). The ratio root diameter to crown diameter will dictate the amount of tissue that can be removed interproximally, pending that corrections can be made entirely in enamel, to avoid dentin exposition or root proximity.

Bleaching

A problem of tooth color often appears when cuspids are in a more mesial position. These teeth present a more saturated color (normally, similar hue but higher chroma) when compared with incisors (Fig. 3c). After the required enameloplasty has been made, the color correction should be tried, using one of the available bleaching techniques for vital teeth, namely chair-side bleaching or home bleaching (6-8).

Direct Composite Bonding

Modern composite resin kits provide very performant restorative materials. Beside the dramatic improvements made in their physico-chemical properties, modern composites have satisfactory color stability and esthetic potential (11-13). Among the various layering options, the one gaining popularity is the Natural Layering Concept (14), which corresponds to a bilaminar, anatomical application of dentin and enamel like shades which closely emulate natural hard tissues. When forms or dimensions have to be only slightly modified, a monolaminar approach can be followed, using exclusively an enamel shade. For larger corrections, the bilaminar approach with dentin and enamel masses is to be applied (Fig. 3d, 4d -4f) (i.e: inspiro, Edelweiss DR AG).

Gingival and periodontal recontouring

In many circumstances, gingival recontouring is indicated to correct minor defects of soft tissue contours or to modify the clinical crown length. This can be made by using electro-surgery or traditional surgery (Fig. 4b), pending the procedures respect the biological width and do not result in an excessive loss of keratinized gingiva.

Conclusion

The two basic therapeutic attitudes for the replacement of anterior teeth in young patients are space closure or maintenance, which respectively require orthodontic or prosthodontic procedures to be applied. To satisfy new demands regarding tissue preservation, function and esthetics, treatment decisional parameters have to be redefined. An extended list of general, local and secondary parameters have now to be taken into consideration in order to propose the patient the best available solution.

The most common problems following orthodontically transposed teeth are unusual function, shape, dimension and color or deficient periodontal integration as a problematic long term maintenance of prosthetically replaced missing teeth, using or not implant supported restorations. This article has presented clinical outcomes summarizing the benefits and positive impact of direct composite application to improve esthetics and function following orthodontic space closure.

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