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science & practice 13ICOI World Congress XXXII mains.If2implantsareinsertedside by side, the supracrestal biological widthandthepapillaasresultdisap- pear, independent of the implant type used.7 The effects of implants with platform switching, concave abutments, micromachined neck or implant abutment micro-move- ments onto the stability of crestal bone and soft tissues are limited to subclinical notice.8, 9 The interim- plant distances primarily follow prosthetic requirements of the residual dentition.10 From anatomy, thepresentrulesoccur: 1.Minimal distance between single- rooted teeth incl. premolars: 7mm. 2.In molars interimplant distances ofatleast11mm(Fig.8). For appropriate implant place- ment according to prosthetics, the local bone anatomy is often inade- quate, especially in patients with cross-bite or long-term periodontal damageetc.(Fig.9).Iftheclinicalset- ting implicates deficient implant bone support, 3-D digital imaging of alveolar bone including individual- ized implant positioning with diam- eter-reduced implants is allocated. Note:Priortosurgery,calculateaddi- tional efforts, extent and expenses of alternative augmentation, bone graftingorallogeneicbonegraftsin- cluding pedicle flap surgery and in- fection due to soft tissue advance- ments. Implantplacement Perfusion Maintenance of vascularized im- plantboneisindispensabletoavoid further periimplant damage as re- sult of spongious bone tissue injury during implant surgery (early im- plantfailures).Withinimplantinser- tion, bleeding of cortical bone fol- lowing drilling is a necessary re- quirement for uneventful healing and integration of the implant into surrounding tissues (Fig. 10).11 The followingstepbystepprocedurehas beenproveneffective: a)Utilizationofkeenpilotundmulti- use tapping drills (renew early, otherwisehighdrillingforcesand danger of deviation from drilling axisoccur). b)Intermitted implant bed prepara- tion under permanent cooling with0.9%saline. c)Prior to implant placement, wait untilimplantbedhasbeenreplen- ishedwithblood. d)Wetting of implant surface with bloodpriortoimplantinsertion. e)Limitedrotationspeed<800r.p.m during implant bed preparation, hand implant placement with torque key, max. 10–30Nm, if ap- plicable. Aslightsubcrestalpositionofthe implant is advisable as drilling end- point.12 Toensurehealing,aprimary fixationoftheimplantismandatory for all implant types (cylindrical, root-formed etc.), bone quality and anatomical localization. The au- thors strongly discourage from fur- ther„screwing“toavoidongoingtis- sueinjuryoftheimplant-bone-inter- face.13 Periimplant tissue (volumen) Due to alveolar bone defects resulting from tooth removal, peri- odontitis or dysfunction, the condi- tionsofperiimplantkeratinizedgin- giva around implants are not ade- quate.14 Safeguarding implant plan- ning and surgery, the additional duesofsofttissuesurgerytoenlarge periimplant gingiva should be im- plementedintothequotation: Enlargement: Initially,implantplanning(notto forget cast models) and implant placement. During implant inser- tion into local bone, enlargement of periimplant gingiva with a ridge in- cision 1–2mm orally is usually ade- quate. In lateral augmentation in the maxilla,periimplantenlargementis frequently mandatory as result of flap advancement to cover the de- fect. During healing and prior to im- plantexposure,vestibuloplasticsur- gery with free autogenous gingival graft from palate at implant site in a separate visit (Figs. 11 & 12). In indi- vidual cases and edentulism in the mandible,periimplantenlargement with Edlan Mejchar-Vestibuloplas- tic surgery to create attached mu- cosabyapedicleflapwithadequate esthetics prior to implant place- ment.Also,toachievesofttissuepro- tection following implant insertion (Figs.13&14). Thickening: To safeguard implant placement and protect against periimplant dis- eases, an adequate periimplant width is more needed than soft tis- suethickness.Followingthickening byfreeautogenoussofttissuegrafts from the palate or roll flap, loss of periimplant dimension is antici- pated due to shrinkage and further scarformation.Periimplantthicken- ing is limited to individual patients with esthetic needs in the upper front of the maxilla. Shortcomings following healing, scar formation, normal biologic resorption and fail- ingoflong-termstabilityareusually compensated by individual pros- thetic abutments and ceramic crowns with a wide periimplant shoulder. Short and diameter-reduced implants The usage of short implants <9mm demands minimalization of surgery. Implant placement and healing are customer-friendly. How- ever, micro-incision surgery re- quiresadditionaleffortsby3-Dimag- ing(DVT)duringplanningandsensi- tiveness in clinical realization. Evi- dence-based clinical data for short and diameter-reduced implants are inconsistent and industry-driven. Biomechanical research underesti- matesthefunctionaladaptivecapac- ity of implant bone.15, 16 In clinical practice, vertical alveolar bone loss isthemostfrequentdemand: Mandible: 1.Advanced alveolar bone loss in premolars and molars (numer- ous). 2.ProximitytoN.alveolaris. Maxilla: 1.Close anatomical relationship to sinusmaxillaris. 2.Atrophied or edentulous maxilla following longterm appliance of removabledentures. Horizontalalveolarbonedefects, as result i.e. of longstanding peri- odontitis, are compensated surgi- cally during implant placement to avoidextendedimplanto-prosthetic abutmentssusceptibleforrecurrent soft tissue infection (Fig. 15). Fixed implanto-prosthetic restorations of the partially endentulous mandible are achieved with axially screwed, uncemented and unlocked crowns to improve hygiene and avoid fur- therdamagebycementingandperi- implantitis. Integration in clinical practice is successful with focus on tissue biology and both renuncia- tion from mechanical dentistry and interlockingtheories. Diameter-reduced(<4mm),small implants(minis)allowingtransgingi- valhealing.Accordingtotheirmate- rial properties (fracture) and re- stricted implanto-prosthetic indica- tions and compatibility, Minis are limited to individual applications in multimorbid subjects with edentu- lousmandible,enhancedriskforsur- gery i.e. advanced diabetes mellitus orhematopoieticdiseasesandhand- icapsfororalhygiene.17 Augmentation and revision Except for sinus floor grafting, the number of augmentative im- plant surgery is declining and con- fined to reconstruction following trauma and tumor by vertical dis- traction or individual prosthetic or esthetic settings.18 The indications for surgical augmentation during implantplacementinclude: a)Toothlossincross-bitesettings. b)Lateralalveolarbonedefects(pre- molarsandmolars). c)Modelling of periimplant bone in esthetically demanding situa- tions at incisors and canines (emergenceprofile). The authors have recently re- portedabouttheuseandimplemen- tationofautogenousboneandspon- gious bone chips and their syntheti- cal alternatives in implant surgery indetail.19 The regressive developments of implant augmentation in clinical practiceimplicatedirectrecommen- dations for surgical revision of peri- implant defects. The following pro- cedureisadvisable(Tab.1).20 Mucositis: –Defect depths ≤3mm: Oral hy- giene and implant cleaning (hy- gienist). –Defectdepths≤4–5mm:Addition- ally 0.2% CHX, Er:YAG decontami- nation,ifapplicable(dentist). –Defectdepths≥6mm:Periimplant plus periodontal cleaning, sys- temic antibiotics: amoxicilline 500mg20TandClont400mg20T, t.i.dfor7days. Together with decompensation by occlusal appliances (mentioned above), safeguarding by front-ca- nine equilibration and removal of implanto-prosthetic restoration, the clinical situation often improves. The procedure can be easily re- peated. The recommendation to re- movably screwfix implant restora- tions axially (only premolars and molars) is becoming a strong rele- vance in the treatment of periim- plantdamage. Periimplantitis: Advanced periimplant damage with circumferential angular bone lossencompasses –Defect depths ≥8mm: Explan- tation,surgicalrevision(ifapplica- ble). Intheseclinicalsettings,implant removal with repeated insertion, augmentation (where appropriate) andprostheticrestorationfollowing healingisadvocated,iftheclientap- proves the treatment. In periim- plant damage, the benefit of rapid implant bone healing following in- sertion of short and diameter-re- ducedimplantsbecomesobvious.In individual, strategically important implant sites, i.e. canine implant area in edentulism, revision is emp- hazised with the following surgical protocol(Tab.2).21 –Removal of implanto-prosthetic restoration,ifscrew-fixed. –Horizontal ridge incision with a mucoperiostalflapandmesialver- ticalextension. –Curettageofimplantbonedefect. –Irrigation with 0.2% CHX, supple- mented by Er:YAG-decontamina- tion. – Stimulation of bleeding plus au- togenous bone grafts for defect fill and reconstruction, defect coverage with rotated pedicle soft tissue flap. –Close,tension-freewoundclosure, nofunctionalloading. –Systemicantibiotics. Summary The prevention of periimplant diseases is based on a comprehen- sive analysis, evaluation and plan- ningpriortoimplantplacement.Se- curing the residual dentition from periodontal disease, on time re- moval of compromised teeth and functionaldecompensationwithfo- cus on front-canine equilibration are the key issues during implant planning.Priortosurgery,DVTdiag- nosticevaluationisrequiredifprox- imitytoanatomicalstructuresisan- ticipated, and short and diameter- reduced implants are advocated to determine interimplant distances and safeguard implant treatment. Implant placement succeeds with minimal mechanical loading of im- plant bone and implementation of perfusion during surgery. Periim- plantenlargementisscheduleddur- ing implant healing, either by free gingival graft or pedicle flap. Pre- molar and molar implant restora- tionsarescrew-fixedaxiallytoease handling in case of periimplant damage. The concerted action of eliminating inflammation, stabiliz- ing function while minimizing sur- gery secures implant success, pre- ventsperiimplantdiseasesandpro- motes the reputation of dental health care providers in the com- munity. The authors appreciate the encour- agement and support of Dr Gerhard Kochhan, Düsseldorf, in periimplant cooperation. Editorial note: A list of references is availablefromthepublisher.Thisar- ticlewaspublishedinthe03/2015is- sue of implants, international maga- zineoforalimplantology. Surgical Reentry 1.Removal of suprastructure (screw-fixed). 2.Horizontal alveolar ridge incision with vertical mucoperiostal flap reflection. 3.Intrabony defect curettage. 4.0,2% CHX irrigation,Er:YAG-decontamination. 5. Stimulation of spongious bleeding plus autogenous bone grafts for defect fill and reconstruction. 6.Close,tension-free defect closure,no functional implant loading. 7.Systemic antibiotics. Periimplant Therapy Step Defect (PD in mm) Treatment A ≤ 3 mm Oral Hygiene + IMP Cleaning B ≤ 4–5 mm CHX 0.2 %,Er:YAG C ≥ 6 mm SystemicAntibiotics D ≥ 8 mm Implant Removal/RegenerativeTherapy Table 1: Key treatment issues to combat periimplant damage, to a large extent being prevented by early and carefull implant planning. Table 2: Surgical revision of advanced periimplant bony defects is limited to single clinical set- tings due to the time and extent of surgery and additional patient expenses. “Safeguardingimplanttreatmentcommenceswithcareful toothremoval,pre-implanttreatmentandimplantplanning.”