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Continuing EducationVolume 33 No. 2 Page 106How to Optimize an ExistingRemovable Partial DentureUsing Narrow-Diameter Implants toIncrease Support and RetentionAuthored by Steven H. Pratt, DDSUpon successful completion of this CE activity 1 CE credit hour will be awardedOpinions expressed by CE authors are their own and may not reflect those of Dentistry Today. Mention ofspecific product names does not infer endorsement by Dentistry Today. Information contained in CE articles andcourses is not a substitute for sound clinical judgment and accepted standards of care. Participants are urged tocontact their state dental boards for continuing education requirements.

Continuing EducationHow to Optimize an ExistingRemovable Partial DentureUsing Narrow-Diameter Implants toIncrease Support and RetentionEffective Date: 2/1/2014Figure 1. Thepatient’s “do-ityourself” repair,done with a kitpurchased atWalmart.Expiration Date: 2/1/2017ABOUT THE AUTHORDr. Pratt received his DDS from theUniversity of Texas Health ScienceCenter at San Antonio in 1981 andbegan private practice that year in hishometown of Atlanta, Tex. He beganplacing and restoring dental implants in1988. Today, his practice offers all phases of generaldentistry, including comprehensive surgical and restorativephases of implant dentistry. Dr. Pratt holds Fellowships fromthe AGD, the American Academy of Implant Dentistry, andthe International College of Dentists. He has attended6 world symposiums on dental implants in 5 foreigncountries. He has had several of his implant casespublished in national journals and has spoken on thesubject of dental implants to educate both the public and hispeers in the practice of general dentistry. He has also beeninvolved with the Texas Dental Association’s Texas Missionsof Mercy and Smiles on Wheels where he has donated hisservices to those in need. He can be reached via e-mailat stenorpra@att.net.Figure 2. Resorbedlower posterior archwith insufficientbone width to placestandard sizedimplants withoutgrafting.Figure 3. Theexisting lower partialframework fit well.Disclosure: Dr. Pratt has no financial interest in any of thecompanies mentioned in this article, but did receivecompensation from ZEST Anchors for writing this article.dentures (RPDs).2 Recently, when this author polled anaudience of surgeons who place implants and dentists whoroutinely restore implants, only 20% stated that they hadused dental implants to help retain/support RPDs.This utilization of dental implants can easily beincorporated into general and prosthodontic dentalpractices to aid the numerous patients who otherwise mightnot be able to function optimally and comfortably with theirRPDs. Among the reasons patients often choose an RPDover other restorative options are financial or healthINTRODUCTIONAlthough dental implants are now widely used forsupporting fixed prostheses and retaining or supportingcomplete dentures, their use in North America is stillminimal when compared to the proven need.1 A review ofthe literature reveals that dental implants are not nearly aswidely used for supporting or retaining removable partial1

Continuing EducationHow to Optimize an Existing Removable Partial Dentureconcerns, lack of a distal abutment for a fixedpartial denture, or lack of desire to commit tothe time involved with bone grafting andsubsequent implant placement for a fixedprosthesis.Unfortunately, what patients usually donot realize is that an RPD, especially amandibular Kennedy Class I or II prosthesis,can actually cause severe bone lossthroughout time. In conjunction with an upper Figure 4. Panoramic radiograph reveals sufficient height to place 12-mm and 10-mmimplants in first premolar and second molar sites, respectively.complete denture, the Kennedy Class Iprosthesis is known to contribute tocombination syndrome first described byKelly3 in 1972. This bone loss can beprevented or minimalized under a new RPD,or slowed or eliminated under an existingRPD, with the use of dental implants.In many cases, if a patient has beenwearing an RPD for a while, the bone lossmentioned above may be severe enough thatFigure 5. Diagnostic model with drill guidesFigure 6. Vacuum-formed .060 surgicalstandard-sized implants cannot be placed placed, ready for .060 thermoformedstent trimmed and ready for sterilization.without bone grafting, which can be both surgical stent material.expensive and time consuming. If the patienthas insufficient bone for standard-sizedimplants and cannot afford or doesn’t want topursue bone-grafting procedures, smalldiameter implants (SDIs) may be the implantsof choice. Since FDA approval for “long-termintrabony applications” in 1997, SDIs havegrown in use and public awareness.4For many patients, SDIs offer severalbenefits over standard-sized implants. Theycan often be placed with no or minimal soft- Figure 7. The LOCATOR OverdentureFigure 8. The 2-piece design of the LODItissue reflection. They can be placed in Implant (LODI) (ZEST Anchors) can save as allows the clinician to easily replace themuch as 3 mm of vertical height over an oLOCATOR abutment (ZEST Anchors), ifnarrower ridges than standard-sized implants ball type attachment.attachment wear occurs throughout time.without bone grafting. Small-diameter implantscan often be placed at a fraction of the cost of standard-sizedCASE REPORTimplants, even though 2 SDIs are typically placed in the placeDiagnosis and Treatment Planningof one standard-sized implant.A 70-year-old female presented with a chief complaint of aThe following is a case in which a patient with a typicalbroken maxillary denture. While out of town, she attemptedmandibular Kennedy Class I RPD was unable and unwillingto repair the fractured denture with a denture repair kit thatto wear her partial due to its mobility while eating. SDIswas purchased at Walmart (Figure 1). She gave a history ofwere utilized to correct this problem.having “3 upper dentures made in as many years.” She said2

Continuing EducationHow to Optimize an Existing Removable Partial DentureFigure 9. Surgical stent “snapped” intoplace by engaging undercuts on teeth Nos.22 to 27, utilized at this time to markosteotomy sites with 1.2-mm pilot drill.Figure 10. Small flaps reflected to conserveattached gingiva.Figure 11. Paralleling pins in place afterosteotomies prepared. Site No. 31 angledbuccally to avoid lingual undercut.Figure 12. Closure obtained with 4-0Cytoplast PTFE sutures (OsteogenicsBiomedical).Figure 13. Immediate post-op panoramicradiograph.Figure 14. Two weeks post-op, immediatelyafter suture removal.framework fit the existing teeth very well (Figure 3). A panoramicradiograph revealed that there was sufficient bone height in theposterior mandible to place 12-mm implants in the first bicuspidsites and 10-mm implants in the second molar sites (Figure 4).It was explained to the patient that she seemed to be anexcellent candidate for narrow-diameter implants to helpsupport and retain her loose (but otherwise well fitting) lowerpartial. A treatment plan was presented to her that consistedof a new maxillary denture, 4 narrow diameter implants in theposterior mandible, and rebasing her existing partialframework. The patient accepted this treatment plan and wasready to get started as soon as her work schedule allowed.that all 3 had broken in the anterior region and anteriorteeth had broken out of them. Since she did not sleep withher denture in, she attributed this problem to the fact thather lower RPD was loose and always came out when shewas trying to eat. For this reason, she did not wear herlower partial, chewing only with her lower natural teeth(teeth Nos. 22 to 27).Her medical history revealed that she was on a bloodpressure medication, which controlled her blood pressurewithin normal limits. No other significant findings were noted.Clinically, the maxillary arch was fairly well preserved withoutthe significant anterior resorption that is usually seen in cases inwhich lower anterior teeth oppose a maxillary denture.Edentulous areas in the lower arch were resorbed to the extentthat placing standard-sized implants would be impossiblewithout bone grafting. However, there appeared to be sufficientbone to place narrow-diameter implants (Figure 2). Although herlower partial was not retentive enough for her to eat with, theTreatment ProtocolImpressions were made for diagnostic casts and for thefabrication of a surgical stent to aid in the placement of themandibular implants (Figures 5 and 6). Whenever possible,this author prefers to use a restrictive surgical stent to allow3

Continuing EducationHow to Optimize an Existing Removable Partial DentureFigure 15. Alginate pick-up impression ofthe lower partial rebase impression.Figure 16. Black processing males andmetal housings placed on LOCATORabutments.for precise placement of parallel implants.The implant of choice for this application was theLOCATOR Overdenture Implant (LODI) (ZEST Anchors). Available in diameters of 2.4 mm and 2.9 mm, the 2.4-mm diameterimplant was ideal for this patient’s thin ridges. The LODI waschosen instead of mini implants with a ball attachment dueto the need for decreased vertical height (Figure 7). Thisauthor has used the LOCATOR Abutment on standardsized implants for years, preferring the varying degrees ofretention that are available versus the retention offered withball type attachments. The LODI was also chosen over a onepiece clone of the LODI due to the fact that the abutment canwear throughout time, especially if patients are not meticulousabout rinsing abrasive toothpaste from both their mouth andthe intaglio surface of their prosthesis. The LODI, being a 2piece implant, allows for changing worn abutments at a laterdate (Figure 8).At the surgical appointment, local anesthesia wasobtained by infiltrating around each site buccally and linguallywith a total of 3 carpules of articaine 4% with 1/100,000epinephrine. The surgical stent was placed, and osteotomysites were marked through the gingiva using the 1.2-mm pilotdrill (Figure 9). The stent was then removed and, in order toretain as much attached gingiva as possible, small flaps weremade and reflected (Figure 10). The stent was then replacedand osteotomies were made using the appropriate drills anddrillstops. The osteotomy for site No. 31 had to be angledslightly buccally to avoid a lingual concavity of the mandible inthat area (Figure 11). LODI Implants were then placed; 2.4mm x 12-mm LODIs in the first bicuspid areas and 2.4-mm xFigure 17. Rebased partial with lingual ventholes allowing escape of excess acrylicwhile picking up LOCATOR males.Figure 18.Intaglio surface oflower partial withthe appropriateLOCATOR malesin place.10-mm LODIs in the second molar regions. Insertion torquefor each implant was recorded. All implants seated with aninsertion torque of slightly greater than 30 Ncm (except No.18, which seated to greater than 70 Ncm). Flaps were closedwith 4-0 Cytoplast PTFE sutures (Osteogenics Biomedical)(Figure 12) and a postoperative panoramic image was made(Figure 13). The patient’s partial was relieved to ensure therewas no contact with the LODI Abutments.At the 2-week post-op appointment, sutures wereremoved (Figure 14) and the final impression for themaxillary complete denture was made. Three days later,occlusion rim adjustments, bite records, and a rebaseimpression for the partial were made (Figure 15).At the delivery appointment, which was 2 weeks later,both the upper and lower prostheses were checked forpressure spots using pressure indicator paste (a 50/50mixture of zinc oxide powder and Crisco). After pressureareas were adjusted, vents were cut through the lingualsurface of the lower partial and the LOCATOR housings4