IM0110

I 13 case report _ implant placement I implants1_2010 the aid of the restorative dentist, a prosthetic plan is completed. Parel’sclassificationoftheedentulousmaxillais usefulforconceptualizationoftheprostheticplan. 1) Class I maxilla is the patient who seems to be missing only the maxillary teeth, but has re- tained the alveolar bone almost to its original level. 2) ClassIImaxillahaslosttheteethandsomeofthe alveolar bone. 3) ClassIIImaxillahaslosttheteethandmostofthe alveolar bone to the basal level. For the Class I, a fixed restoration, borne by im- plants, can be fabricated because the patient has adequate alveolar bone for support of the soft tis- sue and is missing only teeth. There is usually greater than 10 mm of bone height for both the anterior and posterior maxilla. For a fixed crown and bridge-type restoration, implants need to be placed within the confines of the teeth of the planned restoration. The Class II patient is rarely aesthetically man- aged with a fixed crown and bridge prosthesis be- cause they require the labial flange of the maxil- lary prosthesis to support the nasal-labial soft tis- sue. A fixed crown and bridge, fixed/removable (spark erosion or milled prosthesis), or removable overdenture type prosthesis require at least 6–8 implants to adequately support a maxillary im- plant-borne prosthesis. The removable prosthesis requires placement of four implants placed into the anterior the anterior placement to support a bar,whichhasretentiveverticalstressbreakingat- tachments. The prosthesis for the edentulous maxilla is usually fabricated with cross arch stabilization of the left and right implant. _Four implants (tissue-borne prosthesis) For an upper implant supported removable overdenture, a minimum of four implants are needed. Generally, when placing four implants for an overdenture, consideration should be given to thepotentialneedforadditionalimplantsatalater timeifthepatientdecidestochangefromatissue- borne prosthesis to an implant-supported pros- thesis. In preparation for a tissue-borne prosthe- sis, adequate bone should be present to allow the placement of four parallel implants that will sup- port four Zest locators and will allow perfect draw of the overdenture (Fig. 1). _Placement of four implants into the anterior maxilla (bar-supported removable prosthesis) For the patient with adequate anterior vertical bone height and for whom a treatment plan has been made for anterior implants for over-denture support, four implants or more should be placed since any less will not predictably resist the forces placed on them. Two implants are contraindicated to retain a maxillary over denture. The bar can be casted (Fig. 2) or a titanium-milled structure (Fig. 3). _Placement of six to eight implants for implant-borne and supported overdenture If the goals of the patient are to have a den- ture/prosthesis that is palateless and does not de- pend on the tissues for support, a sufficient num- ber of implants are required to resist the forces of mastication. In such instances, it is recommended that six to eight implants be used for an implant- supported fixed/removable prosthesis with ade- quate number of implants located posteriorly to supportthemolars.Sixtoeightimplantsinthean- terior and posterior maxilla are used to support a Fig. 7_Upper and lower fixed crown and bridge. Fig. 8_Upper fixed restoration. Fig. 8Fig. 7