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ePaper created 2018-05-16, 11:45:19 | version 1.38.0
THE PROSTHETIC REVOLUTION — the Minimally Invasive Prosthetic Procedures (MIPPs) and new digital tools for the treatment plan Dr. Mauro Fradeani, Italy Minimally invasive prosthetic pro- cedures (MIPPs) Nowadays the demand for prosthetic treatments is steadily rising. The impor- tance given to esthetics in our society is growing, especially among young people, and clinicians ought to be increasingly con- servative in their treatments and take pre- cautionary measures. This type of ap- proach allows the dentist to maintain most of the remaining dental structure while re-establishing the proper relationship be- tween function, esthetics, and duration of the prosthetic restoration. Minimizing the removal of enamel while aiming to satisfy the esthetic expectations of the patient represents a risk for the cli- nician, especially when the remaining tooth structure is already partly worn. When treating a case extended to both arches with a severely worn dentition, the goal of the clinician should be to obtain micromechanical retention and mechani- cal strength though paradoxically limiting the amount of tooth preparation. The goal is to minimize a further damage of the tooth structure due to tooth preparation, maintaining as much enamel as possible. This procedure will allow the clinician to reduce the ceramic thickness of the res- toration without compromising its resis- tance and the final esthetic result. The use of a Minimally Invasive Pros- thetic Procedure (MIPP) will help the den- tist to reduce the biological cost of enam- el removal. The key steps of this technique are the fol- lowing: (1) increase the Vertical Dimension of Oc- clusion (VDO); (2) reduce the thickness of the monolithic ceramic material; (3) preserve the enamel during tooth preparation; (4) adhesively bond the restorations. 1. Increase the vertical dimension of oc- clusion In prosthetic rehabilitations extended to at least one full arch, an increase in the VDO of the patient can be important in order to achieve a successful esthetic and functional result. This procedure will help the clinician to reduce the amount of den- tal tissue removed. By increasing the VDO, the clinician will be able to avoid invasive occlusal preparations and thus be able to bond the ceramic restoration to the re- maining enamel. A permanent increase in the VDO is a safe and predictable proce- dure if done up to 5 mm; any discomfort related to the patient’s new VDO ratio of the patient will normally last no longer than one to two weeks. When determining a modification in the VDO, the clinician may consider the fol- lowing parameters: – clinical evaluation of the required space for restorative material; – interocclusal rest space; – evaluation of the facial proportions; – phonetic sounds (“m” and “s” sounds); – an acrylic preoperative mock-up. Among these techniques, the one most effective in order to gain acceptance of the new VDO by the patient is the evalu- ation of speech, particularly with regard to sibilants or “s” sounds. 2. Reduction of the thickness of the monolithic ceramic material The reduction in the thickness of the ce- ramic material used in the restoration is a great advantage of the MIPP technique. It has been proven that minimal thickness of lithium disilicate occlusal restorations, if supported by enamel, have a high load-bearing capacity, and therefore a high resistance to fracture. The key to the success of the restoration is its adhesive bonding, which must always be on enam- el and involve an etchable ceramic mate- rial. 3. Preservation of enamel during tooth preparation The preservation of enamel during tooth preparations is highly important in order to implement the MIPP technique. Tradi- tionally the recommended conventional thickness in the occlusal area for porcelain restorations is 1.5–2 mm; however, these values can be reduced by using an etchable monolithic ceramic material with a decreased thickness of 0,5–0,8 mm bond- ed on enamel. 4. Adhesive bonding of the restorations Adhesion to enamel can influence the design of the tooth preparation, allowing the clinician to maintain the maximum amount of dental structure and thereby achieve excellent treatment results, in- cluding lower post-cementation sensitiv- ity, improved support of the ceramic restoration and avoidance of endodontic intervention. Moreover, a correctly per- formed adhesive procedure can eliminate the need for extensive tooth preparation, as well as the use of anesthesia. Success will depend on the ability to establish good adhesion between the tooth struc- ture and the porcelain with correct per- 62 — issue 2018 Modern Concepts in Restorative Dentistry Article