Читать книгу Bone and Soft Tissue Augmentation in Implantology - Группа авторов - Страница 45

When assessing the extraoral findings, the position of the maxilla and mandible in relation to each other should be evaluated. Due to the differing development of the position of the alveolar ridge due to the centrifugally oriented atrophy in the mandible and the centripetally oriented course in the maxilla, a pronounced prognathic position of the mandible can occur, especially in edentulous patients. The necessary grafting procedures in these cases do not only restore the vertical jaw relation but also determine the position of the alveolar ridge for the new prosthetic restoration. Due to the loss of the vertical dimension in cases of severe atrophy, the extraoral profile often shows a sunken upper lip or a reduced dimension of the lower third of the face; symptoms of this are often angular cheilitis and Candida albicans infection at the corners of the lips. A pronounced mental crease is a clinical sign.

When planning the type of dental prosthesis in the maxilla, the shape of the upper lip influences the decision about whether a fixed or removable prosthesis can be incorporated. Since even extensive augmentation procedures cannot restore the entire alveolar process, either long crowns or crowns with an attached gingiva through the use of pink ceramic or resin should be delivered. Due to the change in tension of the peri-oral soft tissue with age, the problem is less relevant for elderly patients. For younger patients with a short upper lip, this can lead to unacceptable esthetic results, in which case a removable prosthesis should be provided. In the presence of a long upper lip, the final choice between a fixed (Fig 2-8a to c) or removable restoration should be made during the esthetic try-in with the patient.

Patients with less-pronounced atrophy but with long-term partial edentulousness with loss of vertical dimension often have functional complaints with the temporomandibular joints (TMJs). Allegedly asymptomatic findings then show a lack of acceptance after complete restoration of the support zones and optimization of the chewing behavior. After the now optimally reconstructed oral system, the risk exists for the manifestation of oromandibular dysfunctions. In these patients, early functional therapy should be initiated to assess any risk factors prior to the start of the final rehabilitation. In many cases, functional therapy could be started during the healing periods between the grafting procedures. In this way, one can avoid a situation where, in the further course of treatment, the symptoms of an oromandibular dysfunction are erroneously assigned as a concomitant or side effect of the grafting and implant treatment. If functional therapy cannot be successfully performed due to the reduced dental system and vertical dimension, the treatment procedure should be extended through the use of an implant-supported provisional for a period of time. With the aid of the provisional dental prosthesis, functional disorders could be detected before the final superstructure is fabricated, and necessary adjustments to the bite position could be performed.

Fig 2-8a Fixed implant prosthetic restoration in the mandible and maxilla.

Fig 2-8b Cleaning channels are important for unrestricted oral hygiene.

Fig 2-8c Long upper lip covers the pink ceramic with the cleaning channels.