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6 Dental Tribune Middle East & Africa Edition | May-June 2015mCME > Page 7 Interdisciplinary approach in aesthetic dentistry ByDr.SebastianErcus,Belgium I ntroduction In today’s dentistry, for ren- dering the best comprehen- sive dental services to our aes- thetically driven patients, the paradigm has shifted to an in- terdisciplinary team of special- ists that work together steered by a clinical co-ordinator. This person should be either a multi- competence general dentist or a specialist with additional train- ing outside his or her specialty area. This gives him or her the ability to bring the surgical, or- thodontic, restorative and tech- nical teams together as a whole, following treatment sequences customised especially for the pa- tients’ best interests and expec- tations. The challenge is making the correct diagnosis and selecting the appropriate treatment regi- men. In order to achieve that, the clinician has to follow cer- tain guidelines and understand the relations between teeth and the adjacent structures. Estab- lishing the correct position of the incisal edge of a maxillary central incisor in relation to the lower lip, the correct ratios between the tooth’s width and length, and the level of gingival margin when smiling are very powerful diagnostic tools. In order to aid memory, one may remember it as the 42.2 rule: (a) a maximum of 4 mm of maxillary central incisor display when the lips are at rest (a mini- mum of 2 mm; Fig. 1); (b) a maximum of 2 mm of gin- gival display during smiling; (c) a maximum of 2 mm from the incisal edge of the maxillary central incisor to the lower lip during smiling (Figs. 2 & 3); and (d) the middle third of the max- illary central incisor should be perpendicular to the occlusal plane and the incisal edge should touch the plane (± 0.5 mm; Fig. 4). The correct ratio between the width and length of a maxillary central incisor is 78 to 80 per cent. With the incisal edge posi- tion already determined, we can identify the position of the gingi- val margin (Figs. 5 & 6). Gingival margin positioning should be in accordance with the understanding of six condi- tions present in the oral cav- ity with different aetiologies and treatment regimens: 1. Altered passive eruption when the gingival margin does not re- cede to a level near the cemento enamel junction (CEJ) during tooth eruption. Diagnostically, the gingival margin is located incisal to the CEJ. Treatment options depend on the amount of attached gingiva and the po- sition of the bone relative to the CEJ (as a general rule, the biologic width should be a mini- mum of 2 mm): (a) gingivectomy; (b) osseous resection (ostec- tomy) with or without flap sur- gery (without a flap, it is difficult to control the osseous contour driven by the new gingival mar- gin); (c) apically repositioned flap. 2. Altered active eruption when the osseous crest does not re- sorb to a level 2 mm apical to the CEJ. The gingival margin is still located incisal to the CEJ. This is treated with periodontal surgery with osseous resection. 3. Compensatory eruption when the tooth surface is lost, with the reduction in facial height or ver- tical dimension of occlusion un- affected (short tooth syndrome). Treatment is either restorative or, in the case of hypermobility of the lip, combined with a coro- nally positioned mucosal flap. 4. Delayed eruption followed by early loss of primary maxil- lary incisors, delayed eruption of maxillary permanent incisors or overeruption of mandibular incisors. Diagnostic features are short maxillary incisors, over- erupted mandi bular incisors or a Class III maxillomandibular relation. Bearing the 42.2 rule in mind, treatment should follow incisal reduction done selective- ly with crown lengthening only or crown lengthening combined with orthodontic intrusion of mandibular incisors and possi- ble minimally invasive restora- tion of maxillary teeth. 5. Vertical maxillary excess de- scribed as a hyperplastic growth of the maxillary skeletal base where teeth are positioned far- ther from the skeletal base, an increased facial lower third and excessive gingival display, which is classified according to three categories: (a) Category 1: 2–4 mm of gin- gival display, treated with only orthodontic intrusion, orthodon- tics and periodontics, or perio- dontics with restorative therapy; (b) Category 2: 4–8 mm of gin- gival display, treated with perio- dontics and restorative or ortho- gnathic surgery (Le Fort type I); (c) Category 3: more than 8 mm of gingival display, treated with orthognathic surgery with or without periodontal and restora- tive treatment. 6. Hypermobile upper lip—the average mobility of the upper lip is from 6 to 8 mm from the rest position. More than 8 mm represents hypermobility. Con- sidering that the average dis- tance from the lower margin of the upper lip and the base of the nose (subnasion) is 21 mm, one could take two superimposed photographs with the patient at rest and the patient smiling fully to calculate the lip mobil- ity very easily using the 42.2 rule. Generally normal tooth length is present and dental la- bial aesthetics is good to ideal. The treatment regimen could entail a coronally po - sitioned mucosal flap, crown lengthen- ing with osseous resection or a combination of both (Figs. 8 & 9). Example: Photographs cap- tured at the same magnification opened in Adobe Photoshop: Picture 10: Full smile—length of the central exposed – measure digitally in pixels distance from incisal edge to the lower margin of the upper lip in full smile. Picture 11: Lips at rest – 2 mm central incisor reveal + 21 mm distance lower lip to base of the nose. Incisal edge to base of the nose 23 mm (incisal edge at the correct position). x = distance from the incisal edge to the lower margin of the upper lip in full smile y = the amount of central incisor exposed at rest 23 mm = 1,725 px; x = 900 px; mobility = x – y; = [(23 × 900) / 1,725] – 2 mm; = 12 mm – 2 mm; = 10 mm (Figs. 10–12) Since the aetiology is generally multifactorial, by combining all the clinical data gathered during the initial examination, includ- ing facial, periodontal, ortho- dontic, endodontic and restora- tive data, as well as radiographs and diagnostic photographs, the clinician has the ability to compose a very detailed and comprehensive treatment plan especially for a patient with high aesthetic demands. Following the digitally designed smile concept, balancing the relations between the teeth and adjacent structures will help the clinical co-ordinator and the specialty team propose treat- ment planning to the patient. Presenting the plan in Keynote mCME articles in Dental Tribune have been approved by: HAAD as having educational content for 2 CME Credit Hours DHA awarded this program for 2 CPD Credit Points CAPPmea designates this activity for2continuingeducationcredits. Fig. 1. The level of the maxillary cen- tral incisors in the relaxed position (2–4 mm in women and 1–2 mm in men). Fig. 7. Lower third smile showing altered passive eruption. Fig. 13. Initial lower third when smil- ing. Fig. 4. The middle third of the maxil- lary central incisor should be perpen- dicular to the occlusal plane. Fig. 10. Lower third full smile design. Fig. 2. A maximum of 2 mm from the incisal edge to the lower lip during smiling, example 1. Fig. 8. Delayed eruption. Fig. 14. Findings in order of impor- tance after establishing the incisal edge position on the full smile photo- graph. Fig. 5. Evaluating width to length ratios. Fig. 11. Relaxed position (/m/ sound – ahhh). Fig. 3. A maximum of 2 mm from the incisal edge to the lower lip during smiling, example 2. Fig. 9. A hypermobile lip and a slight vertical maxillary excess. Fig. 15. The wax-up duplicated in a stone model. Fig. 6. Altered passive eruption. The enamel could be exposed by a gingi- vectomy in one appointment. Fig. 12. Superimposed photographs 10 & 11. The red arrow indicates the distance from the incisal edge to the upper lip in the relaxed position. The yellow arrow indicates the height of the upper lip in the relaxed position (~ 21 mm). The white arrow indi- cates mobility of the upper lip from the relaxed to smile position.