Use Of Tilted Implants In Prosthetic .
Int. J. Odontostomat.,8(3):329-335, 2014.Use of Tilted Implants in Prosthetic RehabilitationUso de Implantes Inclinados en la Rehabilitación ProtésicaPablo Naldini*; Enrique Fernandez-Bodereau** & Laura Bessone*NALDINI, P.; FERNANDEZ-BODEREAU, E. & BESSONE, L. Use of tilted implants in prosthetic rehabilitation. Int. J.Odontostomat., 8(3):329-335, 2014.ABSTRACT: Biomechanical measurements show that tilted implants, when part of a prosthetic support, avoid theuse of distal cantilever units. This study included 20 women (78%) and 12 men (22%), aged over 50 years old (89%), with atotal of 156 implants. A delayed occlusal loading protocol was used and the average distal implant length and diameter were10 mm and 4 mm respectively. Patients were followed up for 2 to 5 years after prosthesis connection. The aims of this studyare to analyze the use of tilted implants in prosthetic rehabilitation of maxillae to reduce cantilevers length, and to study thebiomechanical implications of implant-bone interface.KEY WORDS: tilted implants, cantilever, edentulous maxillae.INTRODUCTIONThe rehabilitation of totally edentulous patientsis very important for the restoration of the balance ofthe stomatognathic system. Several treatmentmodalities were identified for the fixed rehabilitation ofthe edentulous maxilla, with and without boneaugmentation procedures. Regular, tilted, and zygomaimplants are treatment modalities that do not requirebone augmentation. However, another treatmentpossibility that requires bone augmentation proceduresis the sinus floor elevation with interpositional bonegrafts. Biomechanical measurements show that tiltedimplants, when part of a prosthetic support, avoid theuse of distal cantilever units. The use of cantilevers isassociated with a higher incidence of technicalcomplications (21.6% with cantilevers vs. 10.3%) (Sanzet al., 2009).In the literature review, it was found that Belliniet al. (2009), observed in a prospective study that tiltedconfigurations showed a lower absolute value ofcompressive stress compared with the non-tilted,indicating a possible biomechanical advantage inreducing stresses at the bone-implant interface. Theresults revealed biomechanical evidence that distaltilting of implants, splinted in full fixed prostheseswithout cantilevers, reduced the amount of stressgenerated around the peri-implant bone whencompared to the levels of stress seen in peri-implantbone with vertical implants and cantilevered segmentsin similar full fixed prostheses (Mattsson et al., 1999).The aim of this study is to analyze if the use oftilted implants in prosthetic rehabilitation of maxillaereduces the cantilevers length, avoids complexprocedures of bone graft in the treatment of edentulouspatients, and improves the biomechanical implicationsof implant-bone interface.MATERIAL AND METHODThis study is a retrospective trial performed inthe Department of Oral Rehabilitation of the School ofDentistry. Patients were included according to ourinclusion and exclusion criteria. 32 patients (22% males and 78% female) participated in the trial, 28% weresmokers, 89% of the subjects were over 50 years old,having an overall of 156 implants located in uppermaxillae. The patients who received the treatment werein need of complete-arch rehabilitation, and presenteda bone situation allowing for the placement of at least*Assistant Professor, Department of Clinical Prosthodontics, Dental School, National University of Córdoba, Córdoba, Argentina.**Professor and Chair, Department of Clinical Prosthodontics, Dental School, National University of Córdoba, Córdoba, Argentina.329
NALDINI, P.; FERNANDEZ-BODEREAU, E. & BESSONE, L. Use of tilted implants in prosthetic rehabilitation. Int. J. Odontostomat., 8(3):329-335, 2014.four implants. The follow up period lasted from 2 to 5years after prosthesis connection. Spearmancorrelation was used for statistical analysis to showany significant association.A delayed occlusal loading pattern was used,and the average length and diameter of the distalimplants was 12.3 mm and 3.82 mm respectively. Threeimplant systems were used: Standard plus(Straumann), Mk3 Branemark (Nobel Biocare) and Single stage (Biohorizons). An implant was consideredtilted when the inclination was over 15 degrees withrespect to the occlusal plane.Patient Selection Criteria (Maló et al., 2006). Theinclusion criteria for the recruitment of the patients were:18 years or older; patients in general good healthcondition, able to undergo surgical treatment (ASA-1/ASA-2); completely edentulous mandible or mandibularteeth with an unfavorable long-term prognosis;adequate bone height and thickness for the placementof implants at least 10 mm long and 4 mm wide withoutthe need for bone augmentation procedures; andinformed consent of the patient.The exclusion criteria were: Presence of acuteinfection at the implant site; hematologic diseases;serious problems of coagulation; diseases of theimmune system; uncontrolled diabetes; and metabolicdiseases affecting bone, pregnancy, or lactation;Inadequate oral hygiene level (full-mouth plaque scoreand full-mouth bleeding score greater than 20%) andpoor motivation to maintain good oral hygienethroughout the study; Irradiation of the head or neckregion, or chemotherapy within the past 60 months;Severe bruxism or clenching Exclusion criteria were;and Chemotherapy and radiotherapy.Surgical Protocol. Antibiotics (amoxicillin 875 mg clavulanic acid 125 mg, Roemmers, Argentina) weregiven 1 hour prior the surgery and twice a day for 7days thereafter. Chlorhexidine 0.12% mouthwash(PlacOut, Bernabo, Argentina) was indicated to be usedthe day before and for 15 days post surgery. Afterpreparation of the patient the surgical procedures wereperformed under local anesthesia with Articaine HCl.4% with Epinephrine 1:100,000 Injection (Sepyocaine with epinephrine 1:100,000), Dexamethasone sodiumphosphate and Dexamethasone acetate, injection(Duodecadrón, Sidus, Argentina). Anti-inflammatoryand analgesic medication (Flurbiprofeno, 100 mg,Gador, Argentina) was administered during 4 daysfollowing the surgery.330Standard procedures were followed for placingthe implants. Implant stability was achieved in all cases through a manual assessment. A mucoperiostealflap was raised along the top of the ridge with relievingincisions on the buccal aspect in the molar area; theposterior implant tilting with about 30º of inclination.Prosthetic Protocol. The scheme was deferred after3 or 4 months. The final prostheses were metal-ceramicand acrylic metal, 75% were screw retained and 25%cement. The prostheses have different length ofcantilevers such as: 0 mm (without cantilever), 5 mm,10 mm and 15 mm.Follow-Up. Patients were frequently called during theearly healing period and after prosthesis connectionfor detecting any signs or symptoms of inflammation/infection in the treated sites. Patients weresubsequently followed up from 2 to 5 years after theinstallation of the prosthesis as appropriate.At follow-up examinations, intraoral radiographswere taken for evaluating bone levels and signs of periimplant pathology. Radiological control consisted incomparing the bone level at the time of prosthesisinstallation with the follow up period. The bone leveland its resorption were measured in each implantdigitalized radiograph through the Image pro-plussystem.Implant Survival and Failure Criteria. An implant wasclassified as surviving if: (1) it fulfilled its purportedfunction as support for a full-arch reconstruction; (2) itwas stable when tested manually; (3) no signs ofinfection were detected during clinical examination; and(4) no signs of peri-implant pathology were seen onthe radiograph. Implants that did not meet the survivalcriteria were classified as failures (5).RESULTSDifferent variables such as sex, age, jaw, numberof implants, length of cantilevers, bone level, restraintprosthetic, opposite dentition, history of periodontaldisease as well as habits like smoking and bruxismwere assessed.The use of tilted distal implants to avoid or reduce the length of the cantilevers showed a success rateof 98.7% over a total of 156 implants, 92 axial medialimplants (100%) and 64 tilted distal implants (96.87%)
NALDINI, P.; FERNANDEZ-BODEREAU, E. & BESSONE, L. Use of tilted implants in prosthetic rehabilitation. Int. J. Odontostomat., 8(3):329-335, 2014.placed for 32 complete superior arches reconstruction.The success rate is 100% and 96.87% for axial andtilted respectively.The study revealed two distal inclined implantfailures. In the attempt to analyze and link the two failureimplants with sex and age, it was noticed that thefailures occurred in women over 50 years of age.Moreover, these patients had a history of periodontaldisease and smoking (Fig. 1). Table I shows asignificant association (Spearman correlation) betweensuccess and variables; setting a p-value of 0.05 forsignificant associations. Therefore, we interpret thatthe failure of at least one of the implants in patients isassociated with the presence of periodontitis and smoking. By analyzing the number of implants supportingfull fixed prosthesis we can observe that failures arehigher when there are 4 implants than when there are6 (Fig. 2). In relation to the length of the cantilever thetwo distal implants failures are seen when the lengthis 15 mm, compared to lengths of 0 mm (withoutcantilever), 5 mm and 10 mm (Fig. 3). When conductingthe radiological control to compare the bone level atprosthesis connection time with the follow up period,an average loss of 0.35 mm can be observedpresenting greater loss in patients with maladaptedprosthetic structure at the distal implant and in thosewho smoke (over 15 cigarettes per day), 1.4 mm and1.9 mm respectively. Both failed implants had screwedprostheses. Regarding opposite dentition, furtherstudies are required to obtain meaningful data since itcould not be appreciated in this protocol.The complete protocol performed in one of thepatients studied was shown in Figure 4.Table I. Show a significant association (Spearman correlation)between success and variables; setting a p-value of 0.05 forsignificant associations. Therefore, we interpret that the failureof at least one of the implants in patients is associated withthe presence of periodontitis and active smoking status.Success/Fail vs.BruxismPeriodontitisSmokerSpearman 0016Fig. 1. The failure of at least one of the implants in patientsis associated with the presence of periodontitis and activesmoking status.FAILURE15FAILURESUCCESSCANTILEVER LENGTHNUMBER OFPATIENTS151014145SUCCESS105 881042012345NUMBER OFIMPLANTS67Fig. 2 shows the analysis of the number of implants whichsupport a full fixed prosthesis. We can observe that failuresare higher when there are 4 implants than when there are 6.051015NUMBER OFPATIENTS220Fig. 3. In relation to the length of the cantilever the two distalimplant failures are seen when the length is 15 mm, comparedto lengths of 0 mm, 5 mm and 10 mm.331
NALDINI, P.; FERNANDEZ-BODEREAU, E. & BESSONE, L. Use of tilted implants in prosthetic rehabilitation. Int. J. Odontostomat., 8(3):329-335, 2014.Fig. 4. A) Panoramic x-ray of one of the patients whose upper dental pieces were removed and four implants were placed,the tilted distal. B) Dental pieces were removed. C) Posterior x-ray view of the surgery to place the tilted distal implants thatavoid the maxillary sinus. The upper molar had not been extracted yet. D) Clinical view of implants in the oral cavity. E) andF) view of screwed prosthesis with metal internalstructure. G) Panoramic x-ray view of the prosthesis placed in patient’s oralcavity. H) Prosthesis placed in patient’s mouth. View of Clinical resolution of the case.332
NALDINI, P.; FERNANDEZ-BODEREAU, E. & BESSONE, L. Use of tilted implants in prosthetic rehabilitation. Int. J. Odontostomat., 8(3):329-335, 2014.DISCUSSIONIn the present study the use of tilted distalimplants to avoid or reduce the length of the cantileversshowed a success rate of 98.7%. The implants thatfailed were the two distal inclined, which may lead toconclude that they have more risk than axial, for theirdistal layout in the arch or inclined position. The successrate is 100% and 96.87% for axial and tiltedrespectively. These results are similar to the onesdescribed by Calandriello & Tomatis (2005), whoseobservations showed survival rates of 97.0% and96.3% for the axial (33 implants, 1 failure) and tilted(27 implants, 1 failure) implants, respectively. Theoverall cumulative implant survival rate was 96.7%. Ithas been shown by intraoral implant loadmeasurements that tilting of an implant that is part of amultiple implant-supported bridge structure does notincrease bone stress per se. Therefore, placing tiltedimplants in posterior maxillary locations has potentialadvantages over the more conventional straight implantalignment (Fortin et al., 2002).To compare survival rate between deferred loadand immediate load we can refer to the following studyby Testori et al. (2008), in which the 1-year implantsurvival rate was 98.8% for both axial and tiltedimplants. Prosthesis success rate was 100% at 1 year.Marginal bone loss around axial and tilted implants at12-month evaluation was similar, being 0.9 0.4 (SD)mm and 0.8 0.5 (SD) mm, respectively. The results ofthe present investigation are in line with previous clinicalreports in which fixed bridges supported by fourimplants were successfully used for the early orimmediate rehabilitation of fully edentulous mandibles.Several authors have also investigated the best positionand inclination of implants. Krekmanov et al. (2000)note some biomechanical advantages of using tiltedimplants. They identified accomplishment of a wideanterior–posterior spread, avoidance of longcantilevers, and achievement of a favorable distributionof the occlusal load. It could also be speculated thattilted implants can be placed and anchored with greatercortical bone contact than axial ones; thereby achievinggood primary stability (Krekmanov et al.; Maló et al.,2012; Jensen & Adams, 2009; Ehsani et al., 2014).Tilted fixtures may also be subjected to bending,possibly increasing the marginal bone stress. However,when the implant belongs to multiple implant supportedprosthesis, the spread of the implants and the rigidityof the prosthetic structure should reduce the bending.In a two-dimensional FE analysis, Zampelis et al. (2007)evidenced that distal tilting of implants splinted in afixed restoration did not increase the stress in the marginal bone compared to axial implants.According to some authors, a limited inclinationof an implant (between 15 and 30 degrees) has noharmful effect for the load transfer to the surroundingbone (Herrmann et al., 2005).Sex and age. In this study, it was noticed that bothfailures happened in women over 50. However, otherauthors describe sex and age as not showing significantdifferences regarding failure rates (Herrmann et al.,2003)Periodontal background: Smoking and Bruxism.Patients with failures had a history of periodontaldisease and smoking. We observed a significantassociation between success and these variables.Therefore, we interpret that the failure of at least oneof the implants in patients is associated with thepresence of periodontitis and smoking. Horwitz et al.(2008), indicate a potential influence of periodontaldisease on the success rate of dental implants. Bonechanges around immediately restored dental implantsin periodontal susceptible patients were slightly higherthan most reports in the literature.Galindo-Moreno et al. (2005), found that on asample of 514 implants in 185 patients, the peri-implantmarginal bone loss was increased in 3 years inindividuals consuming 410 g of alcohol daily and intobacco users compared to those consuming less alcohol and no tobacco; thus, alcohol and tobaccoconsumption jeopardizes the outcome of restorativetreatment with implant-supported prostheses. Thesepatients had a mean peri-implant marginal bone lossof 1.66 mm, very similar to our study in which a greaterloss in smokers (over 15 cigarettes a day) 1.9 mm canbe observed.Number of implants. By analyzing the number ofimplants supporting full fixed prosthesis, it wasobserved that failures are higher when there are 4implants than when there are 6. Herrmann et al.,demonstrated that the number of implants supportingthe restoration did not give any statistically significantdifference. In agreement with our study, this authorstates that the highest failure was seen in the prosthesis333
NALDINI, P.; FERNANDEZ-BODEREAU, E. & BESSONE, L. Use of tilted implants in prosthetic rehabilitation. Int. J. Odontostomat., 8(3):329-335, 2014.supported by 4 implants whereas the failure ratedecreased when either more implants or fewer implantsper restoration were used (Herrmann et al., 2003).Cantilever Length. In relation to the length of thecantilever, the two distal implant failures are seen whenwe have a length of 15 mm, compared to lengths of 0mm (without cantilever), 5 mm and 10 mm. Bellini etal. (2009) concluded that no significant difference instress patterns between the tilted 5mm and the nontilted 15 mm configuration was predicted. The tiltedconfiguration with a 15 mm cantilever was found toinduce higher stress values than the tilted configurationwith a 5mm cantilever. This last study may support whatwas observed in our research.Bone level. When conducting the radiological controlto compare the bone level at prosthesis connection timewith the follow up period, we observed an average lossof 0.35 mm for tilted implants. This is similar to the meanmarginal bone resorption recorded by Calandriello &Tomatis: which was low as 0.34 mm for tilted implantsafter 1 year. This result might be indicating lower stressin tilted implants in coincidence with Zampelis et al.,who showed that distal tilting of implants splinted byfixed restorations does not increase bone stresscompared to normally placed implants.Peri-implant bone loss after 1-year follow-upcould be evaluated in 30 patients (n 60 implants pergroup). Such difference was not significant (p 0.05).At the 1-year visit, all implants were stable accordingto the opposing instrument pressure test. TheofilosKoutouzis & Wennström (2007), studies failed tosupport the hypothesis that implant inclination has aneffect on peri-implant bone loss.Denture retention system. In our study, both failedimplants had screw-retained prostheses. Vigolo et al.(2004), showed that within the limitations of that study,the results indicate that there was no evidence ofdifferent behavior of the peri-implant marginal bone andthe peri-implant soft tissue when cemented or screwretained single-tooth implant restorations were providedfor this patient population. For the method of retention(screw-retained versus cemented), no differences werefound in implant success or survival rates betweenscrew-retained and cemented restorations (Weber &Sukotjo, 2007).Opposite dentition. Meaningful data are notappreciated in this regard; further specific studies arerequired. In agreement with our study, Romeo et al.(2003), assessed two types of dentition opposite to thecantilever prostheses: natural teeth or fixed prosthesissupported by natural teeth (29 patients) and implantsupported prostheses (nine patients), mean values forthese two groups were 0.72 mm and 0.78 mm,respectively. Implant success rate was 97.2% and100%, respectively. Normal standardized distribution(considering 95% confidence level) Z-test did not showany significant resorption difference between the twogroups. Initial null hypothesis was confirmed.CONCLUSIONSThe present study showed good clinicaloutcomes when using two tilted in combination withaxial implants and a full fixed prosthesis forrehabilitation of the edentulous patients with atrophiedmaxillae. Minimal incidence of surgical complicationsand high implant survival rates, througho
The use of tilted distal implants to avoid or redu-ce the length of the cantilevers showed a success rate of 98.7% over a total of 156 implants, 92 axial medial implants (100%) and 64 tilted distal implants (96.87%) NALDINI, P.; FERNANDEZ-BODEREAU, E. & BESSONE, L. Use of tilte
tal implants OR 4 dental implants OR dental AND (tilted implants OR axial implants OR distal tilted implants OR distal angulated implants OR distal inclined implants OR distal angle implants OR axial dental implants OR axia-lly
The term tilted implants refers to implants placed at an angle of normally 30 degrees or more with respect to axially or vertically positioned implants. According to many authors, the use of tilted implants in the posterior maxillary sector offers advantages over axial implants. The placement of
of breast MRI as a screening tool for implant failure.3 TYPES OF IMPLANTS A wide variety of breast implants are used today, including single-lumen silicone implants (Fig. 1) and saline implants, tex-tured implants, double-lumen and reversed double-lumen im-plants, tissue expanders, and stacked implants. Implants can be
and tilted implants and no difference in prosthetic sur-vival between rehabilitations supported only by axial implants or by a combination of axial and tilted implants. MATERIALS AND METHODS This prospective investigation was conducted according to the Declaration of Helsinki of 1975 for bio
theses (FDPs) supported by a combination of both tilted and axially-placed implants and to compare the marginal bone loss (MBL) and implant survival rates (SR) between tilted and axial implants. Material and Methods: A retrospective study has been c
prostheses with distal extensions supported by both upright and tilted implants for the rehabilitation of edentulous jaws and to compare the outcomes of upright versus tilted implants. At 4 study centers, 342 implants were consecutively placed in 65 patients (96 implants were placed in 24 man
(SD 0.67) for tilted implants, with no significant correlation between implant angulation and bone loss. A significant correlation between implant angulation and annual bone loss was obtained for tilted implants only (r 0.52, p .004).Using Albrektsson criteria, the success rate was 89.6% (26 out of
The module scst_user API is de ned in scst_user.h le. 3 IOCTL() functions There are following IOCTL functions aailable.v All of them has one argument. They all, except SCST_USER_REGISTER_DEVICE return 0 for success or -1 in case of error, and errno is set appro-priately. 3.1 SCST_USER_REGISTER_DEVICE
