A Standardized Protocol for Successful Mandibular Implant Overdentures
Dental News Volume XIX, Number II, June, 2012
by Dr. Marwan DAAS, Dr. André ASSAF, Dr. Karim DADA
- Validate the occluso-prosthetic concept chosen for the rehabilitation and to treat the maxillary occlusal plan.
- Visualize the final aesthetic result.
- Determine the prosthetic volume available for the different surgical and prosthetic components.
- Guarantee continuity and ease of transition between the surgical and prosthetic treatments.
- Provide for temporization that is safe for the implant since a stable prosthesis induces less micro-movements.
Fig. 1: The radiological guide is obtained by the adjunction of barium sulphate to the resin.
Fig. 2: The desired position of each implant is determined.
Fig. 3: Perforation of the stent with a round bur, until half of the supporting surfaces.
Fig. 4: It’s possible to widen the perforations by using the first surgical drill….
Fig. 5: …and even the 2d surgical drill.
Fig. 6: The perforations are thus situated within the prosthetic envelop in accordance with the mounting.
Fig. 7: The perforations are thus situated within the prosthetic envelop in accordance with the mounting.
Fig. 8: Later, it is delivered to the patient to wear and keep into occlusion when the scanning is being made. Two bite blocks in Duralay™ resin enable proper positioning of the stent.
The radiographic reconstructions offer the following readings:
Fig. 9: CT scan of mandible with the radio-opaque radiographic stent.
Axial view of reference: the prospective implant emerging points are clearly visualized.
Fig. 10: Coronal oblique cut of reconstruction passing along the lateral incisor.
Fig. 11: Coronal oblique cut of reconstruction passing along the canine.
Fig. 12: Coronal oblique cut of reconstruction passing along the first premolar.
- Transforming the existing CD into an implant overdenture by a chair-side direct connection with self-cure acrylic resin. The technique is delicate, particularly with bars, and the used resins have lower performance and quality than the heat-cure densified denture resins. However, the technique is less costly to the patient.
- Readapting the existing CD by a complete rebasing procedure, the impression being made with the denture. However the patient must accept to remain without his appliance for the few days that are needed for the lab-side transformation.
- Fabrication of a new CD by using the duplicate of the existing CD as a functional special tray 8-11-12. This option answers the previous disadvantages and also provides the patient with a breakdown service denture; however it is the most expensive of all.
Fig. 13: The surgery zone is cleared on the buccal side …
Fig. 14: … and lingually.
Fig. 15: The incisal edge of the anterior teeth is cut down.
Fig. 16: Removable drilling channels are placed at the reference points at incisor areas
Fig. 17: The removable drilling channels s are placed at the reference points at canine areas
Fig. 18: The surgical stent is ready for use.
Fig. 19: A bite record in Duralayâ acrylic resin is first realized.
Fig. 20: Perforations are made facing the attachments.
Fig. 21: Silicone plugs to seal the perforations
Fig. 22: A through recording of the peripheral seal with Permadyneâ orange is made in occlusion first, and then the tray is maintained manually.
Fig. 23: The material present within the tray is removed.
Fig. 24: The wash with Permlastic lightâ material.
Fig. 25: Removing the plugs opens the access to the ball attachments.
Fig. 26: Injection of a medium viscosity polyether (Impregumâ) on the ball attachments.
Fig. 27: Finished impression
Fig. 28: Fitting surface of the finished MOI showing the female parts of the attachments.
Fig. 29: The impression copings must not interfere with the special tray.
Fig. 30: Same as previously, Impregumâ material is injected around the impression copings.
Fig. 31: The finished impression with the abutment analog in place…
Fig. 32: … and the working model.
Fig. 33: The impression copings should not interfere with the tray.
Fig. 34: Finished impression.
Fig. 35: Before separation, the model is mounted on the articulator using the special tray.
Fig. 36: The bar is fabricated according to the lingual and buccal that materializes the prosthetic space.
Fig. 37: The finished bar must be totally passive at its try-in
Fig. 38: The fitting surface of the denture showing the riders in place.
Fig. 39: View showing the setting of teeth and the stabilizing profile of the polished surface …
Fig. 40: … and of the lingual pouch.
- Activation or replacement of the female matrix attached to the denture.
- Replacement of the ball abutment for its wear, a situation that is less frequent than the previous one.
- Activation or replacement of the clips or riders in case of bars.
- Fabrication of a conventional complete denture meeting quality criteria,
- Fabrication of a radiologic stent, based on the finished denture, with the goal of exploring the implant scopes related to each patient,
- Transformation into a surgical stent for a precise placement of the implants,
- Ultimate modification of this stent into a special tray that will pick-up the implant positions.
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Satisfaction of patients fitted with implant-retained overdentures.
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Mandibular overdentures retained by two implants: 10-year results from a
crossover clinical trial comparing ball-socket and bar-clip attachments.
Int J Prosthodont. 2010 Jul-Aug;23(4):310-7.
15- Weinländer M., Piehslinger E., Krennmair G.
Removable implant-prosthodontic rehabilitation of the edentulous mandible: five-year results of different prosthetic anchorage concepts.
Int J Oral Maxillofac Implants. 2010 May-Jun;25(3):589-97.
17- Kleis WK., Kämmerer PW., Hartmann S., Al-Nawas B., Wagner W.
A comparison of three different attachment systems for mandibular two-implant overdentures: one-year report.
Clin Implant Dent Relat Res. 2010 Sep;12(3):209-18. Epub 2009 Mar 31.
20- Andreiotelli M, Att W, Strub JR. Prosthodontic complications with implant overdentures: a systematic literature review.
Int J Prosthodont. 2010 May-Jun;23(3):195-203.
21- Cehreli MC., Karasoy D., Kokat AM., Akca K., Eckert SE.
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Int J Oral Maxillofac Implants. 2010 Jan-Feb;25(1):163-80.