Dental Practice // March-April 2013 // Vol 11 No 500Keys to success for implantplacement in posterior maxillaimplantology ...
Dental Practice // March-April 2013 // Vol 11 No 5 00to achieve adequate initial stability of theimplant2. Limited bone he...
Dental Practice // March-April 2013 // Vol 11 No 500implantology section1. Less invasive procedure.2. Improves maxillary b...
it apical to ridge crest, uncovering theimplant after more than 6 month submergedhealing time, following the progressive l...
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Implant placement in posterior maxilla by Dr. Ajay Singh

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Implant placement in posterior maxilla. Dental implant therapy into the posterior
maxilla has always been and continues to be a
challenge due to various limitations in this
region such as poor bone density, sinus
pneumatization, lateral and vertical bone
resorption, high occlusal forces and area of
limited access. Further, if the implant is
placed into poor density posterior maxilla,
the bone which forms around the osseointegrated
implants does not show very high
bone to implant surface contact (BIC) percentage,
thus in several cases the implant even
after successful osseointegration may fail
once it is restored in function.

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Implant placement in posterior maxilla by Dr. Ajay Singh

  1. 1. Dental Practice // March-April 2013 // Vol 11 No 500Keys to success for implantplacement in posterior maxillaimplantology sectionINTRODUCTIONDental implant therapy into the posteriormaxilla has always been and continues to be achallenge due to various limitations in thisregion such as poor bone density, sinuspneumatization, lateral and vertical boneresorption, high occlusal forces and area oflimited access. Further, if the implant isplaced into poor density posterior maxilla,the bone which forms around the osseointe-grated implants does not show very highbone to implant surface contact (BIC) per-centage, thus in several cases the implant evenafter successful osseointegration may failonce it is restored in function.In past, several modifications to the con-ventional implant therapy have been done tomake the implant successful into the posteri-or maxilla. Achieving the adequate initial sta-bility and bone implant contact are twomajor challenges into the posterior maxilla.Various protocols such as lateral bone aug-mentation using osteotomes, use of wide andlong implant with deeper threads and highpitch value, use of implant with specific sur-face (HA coated implant), submergingimplant platform apical to the ridge crest,bicortical stabilization of implant, and pro-gressive loading of implant have been appliedto make the implant successful into the pos-terior maxilla.Besides the compromised bone density,sinus pneumatization is the great challenge inthe posterior maxilla which results in limitedbone height availability under the sinus. Insuch cases, maxillary sinus lifting and graftinghas been providing promising results. Thesinus-lift procedure was first performed byDr. Hilt Tatum Jr. in 1974 during his periodof preparation to begin sinus grafting. Thefirst sinus graft was performed by Tatum inFebruary, 1975 in Lee County Hospital inOpelika, Alabama. This was followed by theplacement and successful restoration of twoEndosteal implants. After this, suitableinstruments were developed to manage thelining elevation from the different anatomicalsurfaces encountered in sinuses. Tatum firstpresented the concept at The AlabamaImplant Congress in Birmingham, Alabamain 1976 and presented the evolution of tech-nique during multiple podium presentationseach year until 1986 when he published anarticle describing the procedure. Dr. PhilipBoyne was introduced to the procedure whenhe was invited, by Tatum, to be "TheDiscusser" of a presentation on sinus graftinggiven by Tatum at the annual meeting of TheAmerican Academy of Implant Dentistry in1977. Boyne and James authored the firstpublication on the technique in 1980 whenthey published case reports of autogenousgrafts placed into the sinus and allowed toheal for 6 months, which was followed by theplacement of blade implants.LIMITATIONS WITH POSTERIOR MAXILLA1. Poor bone quality (type IV/ D4) - challengeFIG 3 & 6: Dental implant with sharp and self tapping threads at the apical third and self condensing body can beplaced after minimal drilling and achieves high initial stability even into poor density bone.FIG 7 & 8: Set of osteotomes which are used for lateralbone condensation and sub-crestal sinus elevation.FIG 1 & 2: After the osteotomy preparation for the implant 2mm short of sinus floor, the rest of the sinus floor iseither grinded up using diamond tips/burs or fractured up using osteotome and the implant is placed by stabilis-ing its apex into the sinus floor and collar into the crest (Bicortical stabilization)DR. AJAY VIKRAM SINGH AND DR. SUNITA SINGH
  2. 2. Dental Practice // March-April 2013 // Vol 11 No 5 00to achieve adequate initial stability of theimplant2. Limited bone height due to sinus pneuma-tisation and vertical bone resorption ofridge crest3. Reduced bone width because of lateralresorption of posterior maxilla towards thehard palate, which also results in final pros-thesis with facial cantilevering4. Area of less visibility and access5. Proximity with sinus floor, posterior supe-rior artery etc.KEYS TO SUCCESSFUL IMPLANT THERAPY INPOSTERIOR MAXILLA1. Longest and widest possible implantshould be placed2. Bicortical implant stabilization – implantplatform is stabilized into high density cre-stal bone and its apex into high densitysinus floor to achieve adequate initialimplant stability. (Figures 1 & 2)3. Using more number of implants for multi-ple unit prosthesis4. The implant with sharp self tapping deeperthreads should be preferred to achieve highprimary stability in poor density trabecularbone (Figures 3 - 6).5. Implants with faster osseointegrating sur-faces like Hydroxyapatite coated surfaceimplants; SLA surface implants should bepreferred.6. Implant can be submerged 1.0 mm apicalto the ridge crest to prevent its prematureloading and micromovements during itshealing phase.7. Lateral bone condensation using special setof osteotomes to enhance the density oftrabecular bone around the implant(Figures 7 & 8).8. Longer submerged healing period for theimplant.9. Progressive bone loading to enhance thedensity of trabecular bone around theimplant.10. Sinus grafting to regenerate new boneinto the sinus so that longer implant canbe placed. (Figures 9 & 10).To approach the sinus for theSchneiderian membrane elevation and sinusfloor grafting, Tatum advocated twoapproaches lateral as well as crestal. The lat-eral approach is usually preferred when subantral bone is only 3-4 mm and a sinusmembrane elevation is required to be per-formed to more than 4-5 mm. It should alsobe preferred when sinus grafting is per-formed for multiple number of implants.Sub crestal approach is less invasive andshould be preferred in cases where 2-4 mmof sinus elevation is required to place an ade-quately long implant and to stabilize its apexinto the high density sinus floor. The subcrestal approach of sinus elevation was firstperformed by Hilt Tatum in 1974 and pub-lished by Summer in 1994.ADVANTAGES OF THE CRESTAL APPROACH(SUMMER’S OSTEOTOME TECHNIQUE)FIG 18: Crestal bone is exposed using a soft tissue punch. FIG 19 & 20: Implant osteotomy is prepared in the usual fashion about 2.0 mm short of sinus floor.FIG 13 - 17: Various CT sections are showing only 8.0 mm sub-antral bone height and poor bone density. Thus the sinus lifting with sub-crestal approach and placement of 6 x11.5 tapered implant is planned with CT.FIG 11 & 12: Missing maxillary molar (clinical view and radiograph)FIG 9 & 10: After the membrane has been lifted up to the desired height, sinus flooris grafted using autogenous bone or bone substitutes and implant is inserted.
  3. 3. Dental Practice // March-April 2013 // Vol 11 No 500implantology section1. Less invasive procedure.2. Improves maxillary bone density, whichallows greater initial stability of implants.3. Less amount of grafting material isrequired to fill the lifted sinus membrane.4. No barrier membrane is required5. Limited flap elevation is required whichmaintain the blood supply to the lateralwall of the sinus.CASE REPORTA 48 year old female patient, medically fit forthe implant therapy, reported for the replace-ment of missing tooth no.26. Radiographsand dental CT revealed the availability ofonly 8.0 mm bone under the maxillary sinus.A DentaScan also showed poor bone densityat the implant site. To place an adequatelylong implant with adequate initial stability, asinus elevation procedure with sub-crestalapproach was planned. The ridge form wasgood and the marginal tissue was thick, stableand keratinised so the implant placementusing tissue punch was planned. The osteoto-my for the implant was prepared in the usualfashion but 2.0mm short of the sinus floor.Further, an adequate size osteotome wasused to fracture up the sinus floor and lift upthe sinus membrane. The PRF plug whichwas prepared from the venous blood of thepatient was introduced into the osteotomy toguard the sinus membrane against rupture.The bone substitute (HA + β-tcp) was intro-duced into the osteotome and pushed upusing the osteotome which further elevatedthe sinus membrane to the desired height.The implant with deeper threads(6x11.5mm) was then placed and stabilizedinto the sinus floor. Because the implant isstabilised bicortically it achieved a primarystability of more than 35Ncm and theimplant was left to heal with open protocol.The implant is restored in function after 4month of open healing. The follow-up radi-ograph after one year showed stable crestalbone level and new bone regeneration intothe grafted sinus.RESULTThe author practiced conventional implanttherapy in the posterior maxilla for yearswhere he used hundreds of varying designroot form implants in the posterior maxilla.The poor bone density, availability of limit-ed bone height (due to sinus pneumatiza-tion) and high force factors forced him toplace the short length implant, submergingFIG 21 & 22: After the osteotomy has been prepared 2.0 mm short of sinus floor, an adequate size osteotome isused to fracture up the sinus floor and to lift up the Schneiderian membrane.FIG 27: The use of mechanical driver(torque ratchet) is showing that theimplant has achieved primary sta-bility more than 35 Ncm because ithas been stabilised bicorticallyFIG 28 & 29: Implant at the final position. Gingival former is inserted fortransgingival healing of the implantFIG 23 & 24: The PRF (platelet-rich fibrin)is prepared from the patient’s venousblood which was withdrawn beforesurgery and centrifuged in a table topcentrifuge machine. This fibrin is firstinserted into the prepared osteotomyand pushed using osteotome to place itunder the sinus membrane. It provides aprotection to the membrane againstrupture during its further elevation andgrafting. It also enhances the boneregeneration potential of the graftmaterial.FIG 25 & 26: The bone substitute (HA + β-Tcp) is now used to graft the elevated sinus floor and implant is inserted
  4. 4. it apical to ridge crest, uncovering theimplant after more than 6 month submergedhealing time, following the progressive load-ing protocols. This protocol required twosurgical procedures, long healing time andlonger time span to restore the implant.Further, the author faced a considerablenumber of implant failures with the conven-tional protocol because he was able to placeonly the short length implant in most cases.Moreover, to avoid the premature loading ofthe implant during its healing phase he wasrequired to submerge implant sub crestalwhich often resulted in the loss of primarystability. Since the last couple of years, toavoid such problems and to maximize thesuccess rate of implant in posterior maxilla,the Author switched over to long implantsand stabilized them bicortically. Bicorticalstabilization of the implant result in severaladvantages such as placement of the implant4-5 mm longer than usual, high primary sta-bility of the implant, most of the implant areplaced with non submerged protocol, shorterhealing period for the implant (3-4 months),less implants are required to support multiu-nit prosthesis and no progressive loading isrequired in most cases.CONCLUSIONAuthor placed more than 200 implants in theposterior maxilla in a period of 3 years wherehe stabilized the implant bicortically with orwithout sinus grafting. Most of the implantsachieved primary stability more than 35 Ncmand hence placed with non submerged heal-ing protocol. Most implants restored in func-tion after the healing period of 3-4 monthswithout following any progressive loadingprotocol.When the author compared this newerprotocol with the conventional one, he foundmore promising results and a significantlyhigher success rate with the newer technique.Stabilizing the implant apex into the highdensity sinus floor resulted in a higher successrate. The author would like to mention herethat this technique should only be performedby clinicians who have expertise in perform-ing sinus lifting with crestal approach toavoid inadvertent rupture of theSchneiderian membrane and post operativecomplication. Others with less expertise inthis technique should follow protocols suchas lateral bone condensation, placing theimplant platform apical to the ridge crest,using widest possible implant with self tap-ping threads and self condensing body tomaximize the initial stability and to enhancethe bone implant surface contact, progressivebone loading to strengthen the trabecularbone around the osseointegrated implant etc.to achieve a higher success rate of implantplacement in the posterior maxilla.For a complete list of references, email:info@dental-practice.bizDr. Ajay Vikram Singh graduated in 2003 from SaraswatiDental College, Lucknow, and received PG. certificatetraining in Implantology from India. He receivedadvanced level implant training at various centers andcontinuing education programmes in USA and also inAustralia. He has authored a dental implant book“Clinical Implantology” published worldwide by“Elsevier”. He is the founder of International ImplantTraining Centre (IITC), Agra where he trains several den-tists from India and abroad in basic and advanced levelimplantology. He runs a private practice at Dr. AjayDental Clinic & Research Centre, Agra. He can be reachedat drajaydentalclinic@gmail.com.Dr. Sunita Singh received continuing education inesthetic and implant dentistry, and fixed orthodonticsat various centers in India and USA. She has receivedtraining in Cosmetic Dentistry from WashingtonUniversity (USA). She is a member of various presti-gious implant associations and has co-authored thetext book in implantology title “Clinical Implantology”.She has been practicing since 2003 at Dr. Ajay DentalClinic and Research Center, Agra.About the AUTHORSDental Practice // March-April 2013 // Vol 11 No 5 00FIG 31 & 32: Clinical view 4 month after implant insertion. Gingival formeris replaces with abutment.FIG 35: Radiograph one year after restoration is showingnew bone formation into the grafted sinus and main-tained crestal bone level around the implant collar.FIG 33 & 34: Implant is restored in function using cement retained zirconium crown (CZAR- Monolithic, Katara Dental)FIG 30: Post operative radiograph inshowing bicortically stabilizedimplant and grafted sinus.

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