The “Loma Linda Stent ”: A Screw-retained Resin Stent

THE ``LOMA LINDA STENT'':A SCREW-RETAINED RESIN STENTCLINICALPeriklis Proussaefs, DDS, MSJaime Lozada, DDSAlejandro Kleinman, DDSKEY WORDSKeratinized tissueMucogingival surgeryVestibuloplastySurgical stentDental implantsPeriklis Proussaefs, DDS, MS, is in privatepractice in Santa Clarita, CA, and is anassistant professor in the Graduate Program inImplant Dentistry, Loma Linda University,School of Dentistry Center for Prosthodonticsand Implant Dentistry, Loma Linda, CA92350 (e-mail: pProussaef@hotmail.com).Address correspondence to Dr Proussaefs.Jaime Lozada, DDS, is a professor anddirector of the Graduate Program in ImplantDentistry, Loma Linda University, LomaLinda, CA 92350.Alejandro Kleinman, DDS, is an assistantprofessor in the Graduate Program in ImplantDentistry, Loma Linda University, LomaLinda, CA 92350.This article describes a technique in which an acellular dermal allograft is usedin combination with a photopolymerized acrylic resin stent to increase the zoneof keratinized tissue around osseointegrated dental implants. During the secondstagesurgery, a split thickness labial flap is reflected and apically repositionedby being sutured onto the periosteum and connective tissue. The acellular dermalallograft is then sutured onto the recipient site. The acrylic resin is trimmed andsecured with temporary abutments to the implants, fitting passively over thegraft and then photopolymerized intraorally. The stent is left for 1 week to securethe graft in place. This technique offers an alternative mucogingival procedurefor increasing the zone of keratinized tissue around osseointegrated dentalimplants.I threa Tw m t n d l dib e th area ofplantsmanplacede3-5atoestheoanteseerior ture.o Steri-Oss 3.8 3 14 mmo ular dib man r suppo e tissu f o u s h hig r potreatedtment modccessality.1,2rateTheimre-ities, she decidetedd to have an impverdlant-eal- erdentures have become a valid cussing the different treatment moddis- r e f A . l dib o d e y full ular dib man sue suppoImplant-retainNTRODUCTIONrteded or implant-tisov-Universityentulseekingus mantreatmeenttfor hdner-to be adversely affected by the lack ofkeratinized tissue around the implants.3,6 However, the presence of mobilemucosal tissue around the fixtureshas been associated with chronic irritationand patient discomfort.7The purpose of the current reportis to describe a technique that increasesthe zone of keratinized tissue aroundosseointegrated dental implants.CASE STUDYA 67-year-old Caucasian woman presentedat the center for Prosthodonticsand Implant Dentistry at Loma Lindaed TPS-coated root-form implants (NobelBiocare, Yorba Linda, Calif) wereplaced in areas 22 and 27. Implant surgeryand subsequent healing were uneventful.At the time of second-stagesurgery, mobile mucosa was coveringthe area above the implants with a lackof keratinized tissue (Figure 1). It wasdecided to perform mucogingival surgeryaround the 2 implants in order toprovide a zone of keratinized tissuearound the implants.A split-thickness flap was reflectedaround the 2 implants. The mucosalpart was severed8 and, after performingperiosteal fenestration9,10 in orderJournal of Oral Implantology 19''LOMA LINDA'' SCREW-RETAINED STENTFIGURES 1-4. FIGURE 1. Preoperative view. FIGURE 2. A split thickness flap has been reflected. The labial flap is sutured onto the underlyingconnective tissue and periosteum. Two hexed temporary abutments have been adjusted at a 3 mm height above the fixtures. The abutmentsare screw-retained at the fixture level. FIGURE 3. The allograft is sutured onto the recipient site. FIGURE 4. The photopolymerized acrylicresin is positioned passively above the graft and photopolymerized.to prevent muscle reattachment, the labialflap was sutured on the underlyingconnective tissue and periosteumwith a resorbable chromic gut 6-0 suture(Johnson Johnson, Somerville,NJ; Figure 2).Two Steri-Oss temporary nonhexedtitanium abutments (Nobel Biocare)were placed onto the implants. Theheight was adjusted to 3 mm above theimplant level (Figure 2).An AlloDerm acellular dermal allograft(Lifecore, Chaska, Minn)11-14was trimmed and sutured onto the recipientsite with the same suture material(Figure 3). PhotopolymerizedTriad acrylic resin material (DentsplyInternational, York, Penn) was trimmedand placed on the top of the temporaryabutments. The acrylic resin was then20 Vol. XXIX/No. One/2003photopolymerized (Optilux, Kerr, Danbury,Conn; Figure 4).After curing, the stent was removedalong with the attached temporaryabutments, trimmed, and polishedon a lathe unit (Baldor Electric,Ft Smith, Ark) with pumice. The stentwas then placed in the mouth and theabutment screws were hand-tightened(Figure 5). The stent was removed 7days after placement.The healing of the grafted area wasuneventful (Figures 6 and 7). The patientreported minimal discomfort duringthe healing period.DISCUSSIONThe use of acrylic stents in mucogingivalsurgeries has been proposed as away to provide stability and protectionto the grafted area (Table 1).15-26 Thestents can be secured onto the recipientsite through perimandibular sutures,15-21 fixation bone screws,22,23 adhesive,21,24 or osseointegrated dentalimplants.25,26 Typically, the surgicalstents are fabricated in the laboratoryby using an altered cast.23,25 The significanceof the current method (''LomaLinda stent'') is that it eliminates thelaboratory step, reducing the time andcost for the preparation of the stent. Inaddition, the risk of having necrosisbecause of the pressure that the stentmay apply on the graft27 is reduced becausethe acrylic resin is applied passivelyand photopolymerized at a passivestage onto the grafted area.The use of an acellular dermal allograft11-14 eliminates the need of har-FIGURES 5-7. FIGURE 5. The implant-supported, screw-retained stent is placed. FIGURE 6. The grafted area 2 weeks postoperatively. FIGURE7. The final result 6 weeks after the procedure.AuthorMoore15Hall24Sanders and Starshak16Firtell et al17Grguveric et al23Small21Brygider and Bain25Kahnberg et al19Ten Bruggenkate et al22Hughes and Howard18Ziccardi et al26Nystrom et al20Loma Linda stent(2002)Surgical stents described in combination with mucogingival surgeryType of TemplateOverextended impression/acrylic stentAcrylic stentAcrylic stentOverextended impression/acrylic stentModified cast/acrylic stentAcrylic stent border moldedafter surgeryModified cast/acrylic stentAcrylic stentAcrylic stentModified impression/acrylicstentAcrylic stentAcrylic stentPhotopolymerized acrylic resinapplied intraorallyTABLE 1Graft UsedSkinPalatal-buccalPalatalSkinNo graftSkinPalatalBone graftPalatalSkinNo graftHipAllograftPeriklis Proussaefs et alDays inPlace Location Securing MechanismMandible Ligatures/SteinmanpinsAdhesiveLigaturesCircummandibular su-Notreported71010-14MandibleMaxillaMandibleMaxillaMaxilla107-14turesFixation screwsDermatome glue/circumvendibularligaturesScrew-retained on den- MandibleMaxillatal implantsSuspension wires aroundzygomatic archSingle fixation screwCircummandibular su-MandibleMandibleMandible737753turesScrew-retained on dentalimplantsZygomatic arch suspen- Maxilla10 Mandiblesion wiresScrew-retained on dentalimplantsJournal of Oral Implantology 21''LOMA LINDA'' SCREW-RETAINED STENTvesting a free gingival graft from thepalate, which extends the surgical timeand causes postoperative discomfort24in the donor site. However, althoughhistologic analysis,12,13 short-term clinicalstudies,13 and case reports12,14 haveprovided promising results, there areno long-term studies to support theuse of an allograft as the material ofchoice for mucogingival surgeries. Increasingthe zone of keratinized tissuehas been proposed without the use ofany graft material.22,28-30 However, secondaryepithelization has been associatedwith recurrence of the mucogingivalproblem.31-33The described grafting proceduremay extend the total treatment time.The healing of the graft will necessitateadditional time before further prosthodonticwork can be performed. The reportedirritation of the area labially tomandibular anterior implants in patientswearing overdentures,2,7 the enhancedplaque accumulation,34-36 increasedbleeding tendency on probing,37and peri-implant probing depth36,38around dental implants surrounded bymobile mucosa can justify the attemptto increase the zone of keratinized tissue.Alternatively, mucogingival surgerycan be performed prior to implantplacement. However, the pressure appliedby the temporary complete denturemay compromise healing of thegrafted area.In summary, the proposed techniquecan offer a relatively easy andtime-effective technique to increase thezone of keratinized tissue around osseointegrateddental implants.REFERENCES1. Johns RB, Jempt T, Heath MR,Hutton JE, McKenna S, McNamara DC.A multicenter study of overdenturessupported by Branemark Implants. IntJ Oral Maxillofac Implants. 1992;7:513-522.2. Ekfeldt A, Johanson L, IsakssonS. Implant-supported overdenturetherapy: a retrospective study. 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