Please activate JavaScript!
Please install Adobe Flash Player, click here for download

Clinical Master Magazine

issue 1/2015 — 15Implant Dentistry Article papillae and visibility of the collar of the lateral incisor, and there is one significant problem: any aesthetic deficit experi- enced by the patient tends to make them change their smile line, which can happen more or less as a conscious process and this can be a source of significant errors. Analysis of gingival composition is also a determining issue in positioningthe collar of the lateral incisors in a location that is aesthetically optimal. The gull-wing pro- file, wherethe collarofthe lateral incisors is slightly more coronal than that of the front teeth or the canine teeth, is consid- ered to be more attractive according to Chiche5 (Fig. 2). Dental aesthetics As regards dental aesthetics, the propor- tions of the proposed implant supported tooth can reflect two different scenarios: – there is a unilateral missing tooth and the controlateral incisor has normal and aesthetically pleasing propor- tions. The objective will be to create alateralincisorimplantthatisamirror image; – withthesamesituationbutwherethe controlateral incisor is small ; this is a situationthatoccursfrequentlyinuni- lateralagenesiswheretheincisorthat ispresentisriziformor,ifthereisage- nesis of both lateral incisors, the clin- ical examination should gatherthe in- formation required to decide on the dimensions and coronal axes of the proposed lateral incisors. An analysis of the occlusion and the dimensions of the central incisors are the clinical parameters that make it possible to establish the characteristics of the planned prosthetic teeth. Theanatomyofthelateralincisorhasbeen thesubjectofvariouspublications,includ- ing, notably, by Papathanassiou6 who de- fined average dimensions and a typical form (Fig. 3a) and also presented numer- ous morphological variants affecting these dimensions and also other charac- teristics such as the crown/root ratio and the coronal and root axes (Fig. 3b). These morphological criteria, which can now be found using 3-D imaging, have had a sig- nificant influence on the location of im- plants in all spatial planes in order to achieve the goal of harmony of form and dimension. Other publications, such as those by Levin7 and Preston8 make it pos- sible to estimate the width of absent lat- eral incisors on the basis of the central in- cisors (Fig. 4). Establish the ideal width and orientation of the planned prosthetic crown. Implant location A clinically significant deficit signals the needforreconstructionofhardtissuebut, conversely, a site without a tooth with no loss of volume should be subjected to a three-dimensional X-ray, as thick soft tis- sue can hide a lack of hard tissue (Fig. 5). A thin tissue biotype or a lack of attached gingivacanbeasignthatgingivalaugmen- tationsurgerywillberequired,particularly if a bone graft needs to be performed. Occlusion For orthodontic treatments, the anterior guidance should be analysed carefully. It canbetemptingtoincreasetheperimeter of the maxillary arcade in order to obtain, at the least, implant corridors that are sufficiently wide at the level of 12 or 22. However,anoverjetwillmakeitverylikely thatthe naturalteeth will move in relation to the implant prosthesis with highly neg- ative consequences for the sustainability of the cosmetic outcome. Fig.1 Fig.3a Fig.3b Fig. 1 Agenesis of 22, opening of orthodontic space. Fig. 2 Line of intermediate smile. The smile uncovers the papillae and reaches the collar of the incisors (12 and 22 are supported by implants). Fig. 3a Average forms, types and dimensions of the lateral incisor according to Papathanassiou.6 Overall height: 21 mm, coronal height: 9 mm, radical height: 12 mm, mesio-distal cervical diameter: 5 mm, mesio-distal coronal diameter: 6.5 mm, vestibular-lingual cervical diameter: 5 mm, vestibular-lingual coronal diameter: 6.5 mm. Fig. 3b Proximal view photographs showing 10 anatomical variants of lateral maxillary incisors described by the author.6 Fig. 4 According to Levin, following the golden ratio, the width of the lateral incisor y = 0.62x and, for Preston, it is 0.66x (images from Papathanassiou).6 Fig. 5 Evidence of bone deficit at 22 (case shown in Fig. 1) Fig.4 Fig.5 Fig.2

Pages Overview