Mark - Rem Prostho Current Lit Abstract Feb 2012                                        ELsyad/HabibTitle: Implant-Support...
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Implant-Supported Versus Implant-Retained Distal Extension Mandibular Partial Overdentures and Residual Ridge Resorption: A 5-Year Retrospective Radiographic Study in Men Implant-Supported Versus Implant-Retained Distal Extension Mandibular Partial Overde

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Implant-Supported Versus Implant-Retained Distal Extension Mandibular Partial Overdentures and Residual Ridge Resorption: A 5-Year Retrospective Radiographic Study in Men

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Implant-Supported Versus Implant-Retained Distal Extension Mandibular Partial Overdentures and Residual Ridge Resorption: A 5-Year Retrospective Radiographic Study in Men Implant-Supported Versus Implant-Retained Distal Extension Mandibular Partial Overde

  1. 1. Mark - Rem Prostho Current Lit Abstract Feb 2012 ELsyad/HabibTitle: Implant-Supported Versus Implant-Retained Distal Extension Mandibular PartialTable 1 Dimensions of Implants UsedOverdentures and Residual Ridge Resorption: A 5-Year Retrospective Radiographic Study Lengthin Men 8.0 mm 10.0 mm 11.5 mm 13.0 mm Total no.Int J Prosthodont 2011;24:306–3132 Group 1 Group 2 of implantsDiameter Group 1 Group 2 Group 1 Group 2 Group 1 Group3.6 mm 0 0 0 1 1 1 2 3 8Purpose: 1 This retrospective study sought2 to examine posterior mandibular ridge4.2 mm 1 4 2 3 2 2 17resorption under implant-supported and implant-retained distal extension partial5.0 mm 1 0 2 0 1 2 1 2 9overdentures 1in men at3 the 5Total 2 6 end of a 5-year observation period. 5 5 7 34 Group 1 = implant-supported partial overdenture; group 2 = implant-retained partial overdenture.Group 1 - partial overdenture.- The RDP was only supported by the implant (no retention)Fig 1 Implant-supported 15 Men a bImplant-Supported vs Implant-Retained Distal Extension Mandibular RPDs and Residual Ridge ResorptionFig 1a Healing abutment on the cast.Group framework contactoverdenture. surface of the partial overdenture. supported and retained by the implantFig 2 Implant-retained partial Men - The RDP wasFig 1b Metal 2 - 15 on the fitting ELsyad/HabibFig 1c Healing abutment in place. Fig 3 The lower border of the mental foramen (M, M’), the sigmoid notch (S, S’), and the gonion (G, G’) were used to construct the triangles M-S-G and M’- S’-G’, with centers N and N’, respectively. Boundary S S lines were constructed as follows: M-G and M’-G’, A-L and A’-L’ (crest of the residual ridge to the lower border of the mandible perpendicular to M-G and M’-G’), M-N and M’-N’, and G-P and G’-P’ (G-N and a b G’-N’ extended to the crest of the residual ridge at P N P N C1 I and P’). The lines C1-B1 and C1’-B1’ (line from mar- 1I 2C C I 1 B1 2 A A C2I2 1. ginal bone level [point C1, C1’] to first bone-to-implant G B G Fig 2a Ball abutment on the cast. [point B , B ’]) and B -I and B ’-I ’ (line from contact 2 B2 B1 1 1 1 1 1 1Results: point B1, B ’ to implant shoulder [point I1, I1’]) were Fig 2b Gold smart matrix on the fittingc1 M M surface of the partial overdenture. measured at the distal aspect of the implants. TheThey calculated the area of bone loss under a specific area on a CT, and Ldetermined L Fig 2c Ball abutment in place. C2-B2, C2’-B2’, B2-I2, and B2’-I2’ were measured lines at the mesial aspect of the implants.the partial overdenture design prescribedloss asPatients were then divided randomly into two The vertical height for all well.patients relied on lingual bar major connectors, bi- groups according to the overdenture design con-There waswith RPA (mesial assemblies forcuspid abutmentsdistal proximal plate, Aker arm) clasp occlusal rest, cepts employed using a computer program. Group X and Fig 4 in Group 1 as follows: 1 less ridge resorptionwere The areas were crest of than in 18 defined by the defined includedX’ patients treated with implant-supported the residual ridgeGroup 2. and indirect retention from canineretention support, partial overdentures-B -C direct contact of’-I ’-I met- ’- P-C -B -I -I with -A and P’-C ’-B the ’-B ’-C 1 1 1 2 2 2 1 1 1 2 2 2 S Scingulum rests. al framework to the top of lines A-M and A’-M’, M-G and A’ and the boundary each healing abutmentOverall Loss the mandibular cobalt- After construction of in Bone areas: 1). Disclosing wax (Kerr)G’-P’, used intraorally and Y’ (Fig M’-G’, and G-P and was respectively; Y to XGroupalloy frameworks, mm2. Group 2:eliminatewere defined PAIthe trianglesthan that onM’-G’-N’,chromium 1: 6.6 an impression was re- 43.8mm2 by was calculated as (X/Y + X’/Y’)/2. extraneous contact other M-G-N and the respectively. YVertical Height Lossmixturecorded for the distal extension ridges using a top of each healing abutment to reduce lateral forces Pof equal parts medium- and light-bodied polyether on the implants3 and permit axial loading. Group 2 N P NGroup 1: 0.15mm (0.03mm per year) cmaterial (Impregum F and Permadyne LV, 3M ESPE), included 16 patients treated with implant-retained C1 I 1I 2C C I 1 C2I2 1 B1 2 A AGroup 2: 1.03mm (0.21mm per year) via a resilient attachment (Balland an altered cast impression technique was em- 9 partial overdentures G B2 B2 B1 Gployed. Semianatomical acrylic resin teeth (Vitapan, Abutment and Gold Smart Matrix, Dyna Dental M MVita Zahnfabrik)matrices were functionally balancedand balls. The were arranged to ensure related to Engineering). Positioning ringsat 69 kV with a constant Plus, Siemens) was operated were placed over theDiscussion: by direct pickup usingocclusal contact.the denture-fitting surface ball abutments mA/s andspace between the matrices current of 16 to create an exposure time of 16 sec- L L1. Females excluded. The riskwhile each patient bit down onbone acrylicautopolymerizing acrylic resin. The positioning rings onds of elevated a customwere removed to allow vertical play of the denture on occlusal stent connected to the chin stabilizer of theresorption resulting from the influence ofan hormonal factors would require a farloading (Fig 2). unit. The films were processed in automatic pro-larger group every 6 months to check than Fig 5radiographs were tomographycarefully to Patients were recalled of patients this preliminary reference Traced rotational cessor. points and lines. Number 4, 2011 All Volume 24, examined with 307 design permitted.the top ©contactQUINTESSENCE PUBLISHINGspace between THIS select only RESTRICTED TO PERSONAL USE ONLY.. 2011 BY in group 1 and the CO, INC. PRINTING OF DOCUMENT IS those clearly showing all the main points S2.componentsMAYtempting toin presumebe thatThe mandibularTHE PUBLISHER. resorptionS rates in group 1 could be It isof theREPRODUCED OR TRANSMITTEDgroup FORM to traced. PERMISSION FROM ridge heights at thethe NO PART OF BE resilient attachment IN ANY WITHOUT WRITTEN the reducedattributed to the direct metal the mental foramen and the ridge lengths the healing abutments, which2 using disclosing wax. If contact existed between region of frame contact withthe matrices and effective support were measured from rotational tomograms taken atprovides balls in group 2,and amatrices wereseparated from the denture base the “pickup” pro- and prevents denture base rotation. baseline. Relining frequency for both groups was alsocedure was repeated with positioning rings in place. recorded. P N NPointsTwo prosthodontists who were blinded to the A A C I I C 2 2 1 1treatment groups determined the need for relin- Evaluation of Posterior Mandibular Alveolar B B X3. by checking the occlusion and evaluating theing Although not a purpose Bone Changes study, they did not discuss which method of implant of the Y G 2 1 Gtissue restoration using a thin mixture were more satisfied w/ a simple ball (support only), or with fit of the denture base patients M Mof irreversible hydrocolloid impression material retention and support. Bilateral posterior areas tomograms using a method(Alginate CA 37 Superior Pink, Cavex Holland).10 measured on rotational of the residual ridges were L L4. 1.03mm vertical height osseousmeasurement(over 5 to that is not stat sig when compared to of proportional loss that was similar yrs)Data Collection from Tomographic Images 11 bone loss of other implantareaby Wilding et al. by drawing afor the pos- (1.0mm vert loss in first year described terior standardsBoundaries line joining were identified of success typical) for each patient (taken im-Two rotational tomograms the gonion to the lower border of the mental fora-5. Retrospective Studymediately before [baseline] and 5 years after overden- men and the crest of the residual ridge. The areature insertion) were obtained from available patient was expressed as athe gonion, of a lower borderof the mental connecting proportion the further area of the necessary calculations were performed using the6. May/may examination. To standardize all clinical independent of the was thethe re- of trianglerecords during routine not influence bone, which was decisions. of center foramen, and a point that crest assisted drawing program AutoCAD 2008 (Autodesk)tomographic images, the panoramic unit (Orthophos sidual ridge (a posterior triangle formed on each sideIn this study, gonion–mental foramen–sigmoid notch). (Fig 5). a modification was introduced to this method to sub- The mean differences for right and left PAIs were tract peri-implant crestal bone loss from the posterior calculated for each patient. The area difference, mandibular areas (Figs 3 and 4). Therefore, patients which represents bone resorption along the entire308 The International Journal of Prosthodontics who had excessive peri-implant bone loss were ex- ridge length, was estimated by multiplying the aver- © 2011 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY.. of PAI. cluded to avoid misleading values age initial area with the value of the change in PAI. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER. The rotational tomogram films were scanned us- Then, approximate changes in height could be cal- ing a black and white translucent scanner. The land- culated by dividing the change in bone area by the marks were traced on the images and digitized, and average length of the posterior residual ridge.8

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