In 1977, Lew1 developed a passive

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CLINICAL AN OVERVIEW OF THE LEW ATTACHMENT: CLINICAL REPORTS Jack Piermatti, DMD Sheldon Winkler, DDS KEY WORDS Lew attachment Atrophic mandible Subperiosteal implant Root form implant Although the

1 CLINICAL AN OVERVIEW OF THE LEW ATTACHMENT: CLINICAL REPORTS Jack Piermatti, DMD Sheldon Winkler, DDS KEY WORDS Lew attachment Atrophic mandible Subperiosteal implant Root form implant Although the Lew attachment was originally developed to provide retention for overdentures fabricated in conjunction with subperiosteal implants, these attachments can also be used with other types of implants. Two cases are presented to describe the use of Lew attachments, one with a conventional subperiosteal implant, and the other with 4 endosteal implants and an implant connecting bar. INTRODUCTION In 1977, Lew1 developed a passive attachment for retention of overdentures and partial prostheses. Although originally designed for use with subperiosteal implants, use of the Lew attachment (Park Dental Research Corporation, New York, NY) in oral implantology is limited only by the imagination of the clinician. The Lew attachment has 2 positions that are controlled by an internal ring lock. When the patient opens the outer flange, the lock remains open and the prosthesis can easily be removed. When the flange is pushed in (toward the ridge) with slight digital pressure to a closed position, a locking pin engages an opening in the superstructure that secures the prosthesis in position. The attachment can be placed in the dental laboratory or at the chair with Jack Piermatti, DMD, maintains a full-time practice in reconstructive dentistry and dental implant surgery in southern New Jersey. He is a diplomate of the American Board of Oral Implantology, a diplomate of the International Congress of Oral Implantologists, a master of the American Academy of Implant Prosthodontics, and a fellow of the American Academy of Implant Dentistry. Correspondence should be addressed to Dr Jack Piermatti, 709 Haddonfield-Berlin Road, Voorhees, NJ Sheldon Winkler, DDS, is professor of Restorative Dentistry and director of Removable Prosthodontics at Temple University School of Dentistry, 3223 North Broad Street, Philadelphia, PA FIGURE 1. Panoramic radiograph of 43-year-old edentulous Caucasian man. Journal of Oral Implantology 77

LEW ATTACHMENT: CLINICAL REPORTS FIGURE 2. Preoperative intraoral view of mandibular arch. FIGURE 3. Tripodal subperiosteal implant before insertion. FIGURE 4.

2 LEW ATTACHMENT: CLINICAL REPORTS FIGURE 2. Preoperative intraoral view of mandibular arch. FIGURE 3. Tripodal subperiosteal implant before insertion. FIGURE 4. Intraoral view of subperiosteal implant after insertion. FIGURE 5. Recesses in implant casting to accommodate Lew attachments. FIGURE 6. Occlusal view of overdenture showing bilateral Lew attachments in opened positions. FIGURE 7. Undersurface view of overdenture showing bilateral Lew attachments in opened positions. FIGURE 8. Intraoral view of maxillary complete denture and lower overdenture. Note that Lew attachments are in closed positions. 78 Vol. XXVII/ No. Two/ 2001

Jack Piermatti, Sheldon Winkler FIGURE 9. Panoramic radiograph of subperiosteal implant. Note the bilateral recesses to accommodate Lew attachments. FIGURE 10.

Prostheses with Lew attachments are easily removed by patients for cleaning, maintenance, and overnight tissue rest and are easily returned and placed intraorally.

3 Jack Piermatti, Sheldon Winkler FIGURE 9. Panoramic radiograph of subperiosteal implant. Note the bilateral recesses to accommodate Lew attachments. FIGURE 10. Panoramic radiograph of 63-year-old Caucasian woman. autopolymerizing resin. Attachments can be removed from a prosthesis and replaced, if necessary. Prostheses with Lew attachments are easily removed by patients for cleaning, maintenance, and overnight tissue rest and are easily returned and placed intraorally. 2,3 The attachment is made of commercially pure (CP) titanium and is available in 6.0-, 7.5-, 9.0-, and 11.0-mm lengths to accommodate denture base resin of varying thickness. A jig is available for placement of the attachment during the laboratory processing procedure. Weiss and Wimmer 4 discussed the use of Lew attachments with a 2 tapered bar and 7 endosteal implants to retain an implant overdenture. The use of Lew attachments in a conventional subperiosteal overdenture and an endosteal root form, implantsupported bar/overdenture are presented. PATIENT REPORT: SUBPERIOSTEAL IMPLANT A 43-year-old edentulous Caucasian man requested a mandibular fixed implant restoration, as he was having difficulty managing a lower complete denture. All of the patient s remaining natural teeth were extracted 15 years previously, and he had successfully worn complete dentures until the past year. A severely atrophic mandible (Figures 1 and 2) prevented the placement of endosteal implants distal to the mental foramina bilaterally. As the patient refused a bone grafting procedure using the iliac crest as the donor site, a complete mandibular tripodal subperiosteal implant was designed to receive a precision-fit removable prosthesis. The subperiosteal implant was fabricated with a stereolithography technique, rather than a direct bone impression, in order to avoid an additional surgical procedure. A CT scan of the mandible was made, which was transferred to a magnetic optical disk, and a laser-generated resin model was developed. The model was mounted opposing a patient-approved wax-up of a new maxillary denture using the tubestylus technique of Cranin. 5 The subperiosteal implant was cast in surgical Vitallium, and the surgical insertion procedure was performed under conscious sedation with local anesthesia (Figures 3 and 4). A full metal base overdenture with no resin flanges was designed according to the patient s wishes. Four Lew passive attachments engaged prepared holes in the mesobar (Figure 5). At the time of subperiosteal implant fabrication, a refractory (investment) model was made of the casting on its model. An accurate metal substructure could then be fabricated without the need for intraoral impression-making. The metal substructure was constructed during the healing period, which allowed for a metal try-in and verification of passive fit at the first prosthetic visit. Maxillomandibular records were taken, and the lower prosthesis was completed except for the insertion of the Lew attachments. The attachments were directly luted to the lower overdenture with autopolymerizing resin, and the final try-in of the maxillary denture was performed. The completed prostheses (Figures 6 and 7) were remounted, inserted (8 weeks postsurgery), Journal of Oral Implantology 79

LEW ATTACHMENT: CLINICAL REPORTS and the occlusion adjusted where necessary. The upper and lower prostheses were delivered at a subsequent visit (Figures 8 and 9).

4 LEW ATTACHMENT: CLINICAL REPORTS and the occlusion adjusted where necessary. The upper and lower prostheses were delivered at a subsequent visit (Figures 8 and 9). Oral hygiene procedures were demonstrated and the necessary instructions were provided. The patient was extremely pleased with the aesthetics and function of the prostheses and appreciated the additional retention provided by the attachments for the lower denture. PATIENT REPORT: ENDOSTEAL ROOT FORM, IMPLANT-SUPPORTED BAR/OVERDENTURE A 63-year-old Caucasian woman who was unable to function with a complete lower prosthesis presented for evaluation. The patient s remaining lower teeth were extracted 2 years previously. Due to the atrophic nature of the residual ridge (Figures 10 and 11), the recommended treatment plan involved 4 endosteal root form implants with an implant connecting bar and an overdenture. Four 2-piece, single-stage mm implants (Paragon Implant Company, Encino, Calif) were placed in the anterior mandible (Figure 12). After a 4-month integration period, impression transfers were made for construction of an implant connecting bar. An overdenture with bilaterally placed Lew attachments was made using laboratory jigs and metal sleeves fabricated over bilateral cantilevered posterior sections of the connecting bar (Figures 13 through 15). The lower overdenture prosthesis with Lew attachments was delivered along with a conventional maxillary complete denture (Figure 16). Aesthetics, phonetics, and function were acceptable to the patient. CONCLUSION FIGURE 11. Preoperative intraoral view of mandibular arch. FIGURE 12. Postoperative intraoral view after placement of 4 endosteal implants. FIGURE 13. Connecting bar in place over the 4 root form implants. Note the bilateral recesses to accommodate the Lew attachments. Although originally designed for use with subperiosteal implants, Lew attachments can also be successfully used with implant connecting bars. 80 Vol. XXVII/ No. Two/ 2001

Jack Piermatti, Sheldon Winkler FIGURE 14. Postoperative radiograph showing 4 endosteal implants and implant connecting bar in place. FIGURE 15.

Intraoral view of mandibular overdenture with bilaterally placed Lew attachments in closed positions.

5 Jack Piermatti, Sheldon Winkler FIGURE 14. Postoperative radiograph showing 4 endosteal implants and implant connecting bar in place. FIGURE 15. Tissue view of mandibular overdenture with bilaterally placed Lew attachments in open positions. Note the Hader clip in the anterior region. FIGURE 16. Intraoral view of mandibular overdenture with bilaterally placed Lew attachments in closed positions. Two cases were presented in which the patients appreciated the increased retention provided by the Lew attachments. ACKNOWLEDGMENT The authors would like to acknowledge the assistance of Dr A. Norman Cranin during the insertion of the subperiosteal implant framework in the first case described. REFERENCES 1. Lew I, Greene BD, Maresca MJ. The Lew passive retainer for overlay and partial prosthesis. J Oral Implantol. 1977;7: Lew I. The philosophy of the overlay prosthesis terminal dental arches restored with implants and overlay restorations. Part I. J Oral Implantol. 1981;9: Lew I. The philosophy of the overlay prosthesis terminal dental arches restored with implants and overlay restorations. Part II. J Oral Implantol. 1981;9: Weiss AW, Wimmer J. Implant overdenture with a tapered bar and Lew passive attachments: clinical report. Implant Dent. 1997;6: Cranin AN, Klein M, Simons A. Atlas of Oral Implantology. 2nd ed. St. Louis, Mo: Mosby;1999: Journal of Oral Implantology 81

Conus Concept: A Rewarding Complete Denture Treatment

Conus Concept: A Rewarding Complete Denture Treatment Complete dentures have largely become the domain of the denturist due to the dissatisfaction general dentists feel with this treatment. Multiple visits,