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Abstract Selectinganappropriate implant imaging techniquehasbecomea challenging task sincetheadventofadvanced imagingmodalities,andmanyof theseareused for implant imaging.Onimaging,themodalityshouldnotonlyconsidertheanatomybutshouldalsoprovidedimensionalaccuracy. Many dentists use the conventional method, mostly orthopantograph (OPG), in theirroutinepracticeof implantplacement.However,becauseof thedrawbacksassociatedwithOPG,higher technologies, such as computed tomography (CT) and cone beam computed tomography(CBCT), are better accepted. These help improve image sharpness and reduce distortion. Thesetechniquesarenotusedwidelyduetothecosteffect.Therefore,todecideonthetypeofimagingtechnique,allassociatedadvantagesanddisadvantagesshouldbeconsidered,whichwillbebroadlydiscussedinthisreview.

Keywords: implant, bone density, radiology, tomography, cone beam computed tomography

Introduction

To support a fixed dental prosthesis,metalposts are surgically implanted in the jaw.Thesemetalpostsarecalleddental implants(1).Otherthan occupying an edentulous site, an implantshould also satisfy aesthetics while respectingthe surrounding anatomical structures. Whileselectinganoptimal implantsite,certainfactorsshould be considered, including identifyingthe detailed anatomy and determination of theboundariesofthebone,aswellasitsdensityandquality.Anyunderlyingbonypathologiesshouldalsobedetermined(2). Diagnostic imaging helps develop anappropriate and precise treatment plan forimplant patients. Anatomic considerations ofthe area for implant placement should guidethe appropriate radiological modalities (3). Theselection of a type of imaging technique plays amajorroleinachievingtherequiredinformationwiththebestdimensionalaccuracy.Radiographictechniquesplayanimportantroleinpre-surgical,surgical,andpost-prostheticimplantimaging.

Conventional radiographic techniques havebeen replaced by computed tomography (CT)and cone beam computed tomography (CBCT)to gain the maximum amount of informationabout the implant site. Therefore, to determinethe best imaging modality for an intraoralimplant placement, it is important to know theassociated advantages anddisadvantages,whichshall be discussed henceforth in this article. Allthe pertinent published data from the journalsandtextbookswasreviewedfromtheyear1973to2013toformthisarticle.Thekeywordsusedwereimplants,imaging,implantradiologyandimplantdentistry.

Functions of Imaging

Imaging of the implant site is done todetermine whether the patient can toleratethe surgical procedure, to identify underlyingbony pathologies, undercuts and concavities, toassess bone density to know the approximationof vital anatomical structures and to estimatethe dimensions, number, location, orientation,

Review Article Oral Implant Imaging: A ReviewSarika Gupta1, Neelkant patil1, Jitender Solanki2, Ravinder SinGh3, Sanjeev laller4

1 Department of Oral Medicine & Radiology, Vyas Dental College & Hospital, Jodhpur, Rajasthan, 342005 India

2 Department of Public Health Dentistry, Vyas Dental College & Hospital, Jodhpur, Rajasthan, 342005 India

3 Department of Prosthodontics, King Khalid University, PO Box 3263, Abha 61741, Saudi Arabia

4 Department of Oral Medicine & Radiology, PDM Dental College & Research Institute, Bahadurgarh-124507, Haryana, India

Submitted: 11Jul2014Accepted: 17Dec2014

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andprognosisoftheimplanttobeinserted.Theneed for additional bone treatments should beconsidered. Theobjectivesofdiagnosticimagingdependontheamountandtypeof informationrequiredand the treatment period rendered. The timingandtypeofimagingmodalitytobeuseddependsontheintegrationofthephasesmentionedbelow(3): PHASE I (Pre-surgical implant imaging) Todeterminethebonequantityandqualityand an approximation of the implant site withthecriticalstructures,aswellastoplanimplantorientation,allnecessarysurgicalandprostheticinformationisobtainedinthisphase.

PHASE II (Surgical and intraoperative implant imaging) Along with studying the optimal positionand orientation of the implant, intraoperativeimplant imaging helps evaluate the healing andintegration of surgery sites. The correctpositionof the abutment and prosthesis fabrication areensuredinthisphase.

PHASE III (Post-prosthetic implant imaging) Thisphasestartsfromtheplacementoftheimplantandlastsaslongastheimplantremainsin the jaw.Theradiographicsequence forphaseIII imaging is post-prosthetic imaging, followedby recall and maintenance imaging and anevaluationofalveolarbonechange. ThevariousradiographicmodalitiesusedindifferentphasesoftreatmentplanningatvarioustimeintervalsaregiveninTable1.

Types of Imaging Modalities

Imagingexaminations shouldbe conductedwiththeaimofachievingthemaximumbenefit-to-riskratio.Thevarioususefulimagingmodalitiesforimplantplacementsare(3):

Conventionaltechniques:1. Periapicalradiography2. Bitewingradiography3. Occlusalradiography4. Cephalometricradiography5. Panoramicradiography6. Transtomography7. Digitalradiography

Although the crestal bone can be accessedusingabitewing radiograph, it is still of limitedvalueinimplantimagingbecauseithasnoother

associated advantages. Similarly, the maxillaryand mandibular occlusal radiographs producedistorted imagesof the jaw;hence, they arenotusedinimplantimaging.

Advancedtechniques:8. Magneticresonanceimaging9. Conventionaltomography10. Computedtomography11. Conebeamcomputedtomography

Periapical Radiography (PA)Advantages:

1. In pre-surgical phase: PA provides ahigh-resolutionplanarimageofalimitedregionofthejaws.Itactsasahigh-yieldmodality in ruling out dental diseasein a localised area, as well as in theidentificationofcriticalstructures.

2. Insurgicalphase:Itisusedtodetermineimplant/ostetomy depth, position andorientation.

3. In post-prosthetic phase: high-qualityimages of the dental implant and theadjacentalveolarbonecanbeobtained.

4. TheradiationsourcepositiondepictstheprecisionandreproducibilityofPAwithavariationrangingashighas20°.Forthis,a device with straight abutments of theBranemark system has been developed,which isfixed toauniversalfilmholderto make the radiograph. Therefore,reproducible images can be taken forfuturecomparisons.

Disadvantages:1. In pre-surgical phase: Regarding

distortion and magnification, a paralleltechniqueeliminatesdistortionandlimitsmagnification to less than10%3. It isoflimited value in accessing the quantityandqualityofbone,aswellasindepictingthespatialrelationshipbetweenthevitalstructuresandtheproposedimplantsite.

2. In post-prosthetic phase: The implantsurface, where the central ray of theX-raysourcelies,tangentiallydepictstheimplant bone interface. Other regionsof the implant interface are simply notdepictedwellbythismodality.

Cephalometric RadiographyAdvantages:

1. Across-sectionalimageofthejawscanbedemonstratedinthelateral incisororinthecanineregionsbyslightlyrotatingthe

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cephalometer. This view demonstratesthespatialrelationshipbetweenocclusionand aesthetics and is moreaccurate forbone quantity determinations, whichcannot be obtained in panoramic orperiapical images. Implants often mustbe positioned in the anterior regionsadjacenttothelingualplate.

2. It demonstrates the geometry of thealveolus in themid-anterior region andtherelationshipofthelingualplatetothepatient’sskeletalanatomy.

3. Combining this technique with PA willresult in obtaining the quantitativeinformation of the implant site, as wellasinhelpingtoestablishtherelationshipbetween the implant site and criticalstructuresnearthejaw.

4. It is usefulfor completely edentulouspatients,astheycanhelpevaluatetheboneheight using thecross-sectional imageof the alveolus, crown-to-implant ratio,inclinationofanteriorteethinprosthesis,skeletalarchinterrelationship,softtissueprofileandresultantmomentofforces.

Disadvantages:1. The geometryof cephalometric imaging

devicesresultsina10%magnificationoftheimagewitha60-inchfocalobjectanda6-inchobject-to-filmdistance.

2. It failstodemonstratethequalityofthebone,wherethecentralraysoftheX-raydevicearetangenttothealveolus.

3. Information is limited to the midlinearea. Any non-midline structure issuperimposedonthecontralateralside.

4. Accessing a cephalometric machine is

difficult.5. This radiographic technique is operator

technique-sensitive and, if improperlypositioned, it will result in a distortedview.

6. Because lateral cephalometricradiographs use intensifying screens,resolution and sharpness arecompromisedincomparisontointraoralradiographictechniques.

Panoramic RadiographyAdvantages:

1. In pre-surgical phase: The most useddiagnostic modality; theimage receptormaybearadiographfilm,adigitalstoragephosphor plate or a digital charge-coupleddevicereceptor.

2. Complete imaging of both jaws in onefilm.

3. Limited-angle linear tomography(zonography) is used as a means forpatient positioning for making a cross-sectionalimageofthejawsinanattempttomodifythepanoramicX-raymachine.The tomographic layer is approximately5mm thick, which helps determine thedistance between the critical structuresandtheimplantsite,aswellasthebonequantityatthesiteofimplantplacement.

Disadvantages:1. Inherent magnification in the system:

Panoramic radiography demonstratesvertical and horizontal magnification intherangeof15–22%(3).Leastdistortionis seen in the posterior maxilla onthe radiograph. However, in a given

Table1:RadiographicmodalitiesforvarioustreatmentstagesStageoftreatment Time(months) RadiographicproceduresTreatmentplanning –1 Periapical,orthopantograph,tomo,CT,cephSurgery(placement) 0 Periapical, orthopantograph, tomo, CT, ceph

forcorrectionofproblemsHealing 0to3 Periapical, orthopantograph, tomo, CT, ceph

forcorrectionofproblemsRemodelling 4to12 Periapical,orthopantographMaintenance(withoutproblems) 13+ Periapical, orthopantograph (follow up

approximatelyevery3years)Complications Anytime Periapical,orthopantograph,CT(asindicated)Abbreviations: tomo=conventional tomography;CT= reformattedcomputed tomography;Ceph= lateralor lateral-obliquecephalometricradiography.

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plane, horizontal distortion cannotbe determined ormeasurements andimages are completely unreliable (4,5).Alternatively, the vertical magnificationfactorof the imagecanbecalculatedbydividingtheactuallengthoftheobjectbythelengthmeasuredontheradiographicimage(6).

2. Patient positioning errors: Withknowledge, most errors in patientpositioningcanbecorrected.

3. Thepatienthastoleavethesurgicalroomandstandstillforimagingpurposes.

4. The resolutionof the image is lesscomparedtoperiapicalimages.

5. Zonography fails to identify disease atthe implantsiteoraccess thedifferencesinbonedensities(7).

A technique for evaluating the panoramicradiograph for mandibular posterior implants,as well as fora comparison with the clinicalevaluation during surgery was developed byidentifyingthementalforamenandtheposteriorextent of the inferior alveolar canal. However,studies have demonstrated the mandibularforamencannotbe identified<50%of the timeontheradiographfilmand,whenvisible, itmaynotbeidentifiedcorrectly(8).

Transtomography Welander et al (9) described how directdigital transtomographic images could beobtained by combining the translationalmovement with the pendular movement ofthe beam and detector in advanced panoramicmachines.

Advantages:1. Imagescanbeusedforthesamepurposes

asconventionaltomography.2. Immediateresultscanbeobtainedusing

a computer program intra-operatively(especially during blind surgicalprocedures) and measurements can betaken on the screen. This is achievedby positioning the patient using anindividualisedsiliconkey.ThisenablesalimiteddistortionoftheimagescomparedtoconventionaltomographsandCT.

Digital RadiographyAdvantages:

1. The resultant image can be modifiedin various ways, such as grayscale,brightness,contrastandinversion(10).

2. Computerised software programs (i.e.SimImplant)allow for thecalibrationofmagnifiedimages,thusensuringaccuratemeasurements(11).

3. Images are formed instantaneouslyduringthesurgicalphase.

Disadvantages:1. Thesizeand thicknessof thesensorand

thepositionoftheconnectingcordmakespositioning the sensor more difficult insites,suchasthoseadjacenttotoriorthetapered arch form in the region of thecanines.

Digital Subtraction Radiography Subtraction ismore accurate than PA is indepictingchanges,suchasbonevolumeandbonemineralisation, as dark or light shades of grey.It can also depict buccal and lingual changes inthe alveolar bone. However, this technique isof limiteduse in clinical practicebecauseof thedifficultyinobtainingreproduciblePA(3). Magnetic Resonance Imaging (MRI) Gray, Redpath and Smith illustrated thescopeofMRIusedtoobtainsectionalinformationbeforeanosseointegrateddentalimplantisplacedinbone(13).

Advantages:1. Detailsofavailableboneanddelineation

betweencorticalandcancellousbonecanbeclearlyseenonMRI.Thishelpsobtaininformation about maximum implantlength,angulationsandstability.

2. The vital structures are clearly seen asrenderinggoodclinicalresults(3).

3. It is especially beneficial in the case ofsoft tissue imaging,when required (12).T1-weighted sequences are indicated,and an initial pilot scan with a low-resolutiongradientechosequenceshouldbe obtained in all three planes, assuggested by Gray (13). To set uphigh-resolution,fastspinechoaxialslices,thesagittalplanemustbeused.Ofall theseslices,thesliceshowingmarkersisusedtobuilda seriesof cross-sectionalhigh-resolution images perpendicular to theregionofinterest.Usingthis,ascanningplaneparalleltotheareaofinterestissetup to obtainhigh-resolution images. Toprevent the chances of foreshorteningthemeasurement of the available bone,theplaneshouldbesetupinthelineof

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insertionofthedentalimplant.4. MRI allows for a flexible plane of

acquisition without the need forreformatting. It should be noted theslices should not intersect in theregion of interest tomakemultiple siteacquisitions.

Disadvantages:1. MRI is subject to artefacts, geometric

distortion,andareasof signal loss fromferromagnetic material, with the effectsfrom dental amalgam being minor.Cortical bone gives no artefacton MRIand simply appears as an area of a lowsignal.

2. In the post-prosthetic phase, implantsproduce extensive magnetic fielddistortion and signal loss, resultingin minor artefacts. The MRI scans ofpatients with Branemark implants hadonlyminor artefacts comparatively, butonlyaslongasthefixationmagnetswereremovedtemporarily(3).

Conventional Tomography Anappropriatecross-sectionalangulationisdeterminedwiththeuseofscoutfilms,orientationlaserlightorwaxbiteregistrations(14).However,manipulations can be done in the thickness,orientation and anatomic location of the imagelayer, which can also be predetermined. Thecloser and more perpendicular the long axis ofthestructureistotherelativepathoftubetravel,themore likely therewillbe imageblurringandresolution.

Linear TomographyAdvantages:

1. Tomographic images have a uniformmagnificationfactorthatdependsonthedistance between the focus to film andfilmtoobject.Asallstructureslieatthesamedistance,theseimagesarefreefromdistortion.

Disadvantages:1. Lineartomographycausesblurringofthe

adjacentareainasingledimensionwiththeuseofaone-dimensionmotion.

2. Ithasalackofadequatecross-referencingwith standard lateral, frontal, andpanoramic radiographs, due to whichthereisaneedforamentaltransformationbeforeandduringsurgery.

3. Largemetallicrestorationsinteethlying

adjacent to the area of interest maydistortthedesiredimage.

4. It is difficult to identify anatomicalstructures and assess bone topographythrough this technique due to the useof an intensifying screen, causing a lowresolution.

To avoid these disadvantages, the usability ofmulti-directionaltomographyhasbecomeevident(15,16).

Spiral Tomography Inthistechnique,blurredshadowsareplacedatequaldistancesfromeachother inthepartialattenuation zone to obtain topographic imagesusingspiralmovements.Thedoseperturniskeptconstant,anditusesaspecificcomputerprogramfor different areas of jaws, which are definedby a panoramic scout image. A series of fourimages are achieved by using a fixed projectionangle, each 4mm thick and placed 4mm apart.Therefore,eachfilmshowsa16mmsectionofthemaxillaormandibleintotal.Fourexposuresperfilmmaybeobtainedusingafieldsizeof7×10.2cm. The diagnostic quality of the tomographicimage isdeterminedby the typeof tomographicmotion, the section thickness and the degreeof magnification. For high-contrast anatomicalobjectswithgeometriesthatchangeoverashortdistance,suchas thealveolusof the jaws, large-amplitude tube travel and 1mm sections arechosen.

Advantages:1. Magnificationvariesfrom10–30%,witha

highermagnificationgenerallyproducinghigher-qualityimages.

2. For the alveolus, high-quality complexmotion tomography enables quanti-ficationofthegeometry,whileconsideringmagnification.

3. It helps to determine the spatialrelationship between critical structuresand the implant site. An evaluationofthe implant site region with mentalintegrationallowsforappreciationofthequasi three-dimensional appearance ofthealveolus.Thisisachievedbyspacingtomographic sections every 1 or 2 rumapart. The bony quantity available forimplantplacementcanbedeterminedbycompensatingformagnification.

4. Critical structures can be identified byimageenhancement.

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Disadvantages:1. Dense structures, such as teeth,

exostoses, thick cortical plates, anddental materials/ restorations, aredifficulttoblureffectivelywhentheyaremuchdenserthanthestructuresdepictedinthetomographicsection(3).

2. Complex tomography is not of anyimportance indeterminingbonequalityoridentifyingdentalandbonedisease.

3. Conventional tomograms will have aconstantmagnificationthatvariesamongdifferentmachinesandcanbeasmuchas40%.

4. This technique is anoperator techniquesensitivetothesuperimpositionofstruc-turesoutsidetheplaneoffocus,causingsignificant“blurring”oftheimage.

Computed Tomography (CT) Hounsfield invented CT in 1972 (17),and the application of CT has been studied inimaging temporomandibular joint (TMJ) anddentoalveolar lesions, in assessing maxillofacialdeformities and in evaluating the maxillofacialregion pre- and post-operatively. Tangentialand cross-sectional tomographic images of theproposedimplantsitearecreatedbyreformattingthe image data as a means of a post-imaginganalysis.With the advance of current-generationCT,thereformattedimagesareseenwithasectionthickness of 1 pixel (0.25mm) and an in-planeresolutionof1pixelbythescanspacing(0.5to1.5mm),producingageometricresolutionsimilartothatofplanarimaging.Thetissuedifferentiationand bone quality characterisation can be donebyusingthequantitativestructuredensityoftheimage(18)(Table2).

Advantages:1. It helps in the identification of disease

and proximity of vital structures at thesite of implant placement so theproperorientation and position of the implantcanbedetermined.

2. Ithelpsdeterminethebonequantityandquality.

Disadvantages:1. ConventionalCTisassociatedwithahigh

doseofradiation.

ToovercomethelimitationsofconventionalCT, multi-slice helical CT has been introducedrecently.

Advantagesofmulti-slicehelicalCT:1. It reduces patient motion and breath-

holding time during data acquisition,leading to more rapid and extendedanatomiccoveragewithdecreasedimagenoise,areducedpartialvolumeeffectandahigh-contrastimage.

2. Itiseighttimesfasteratprovidingthicktissue slices while acquiring 0.5mmslices.

3. Itprovidesanincreasedz-axisresolutionofthereconstructeddata.

4. Lesswaitingisrequiredfortubecooling.

Cone Beam Volumetric Tomography (CBVT) To overcome the disadvantages ofconventional medical CT scanners, dental CTscannershavebeendevelopedrecentlytoconducta technique called CBCT. An X-ray source anddetectorarefixedtoarotatinggantrytoproduceanimagewiththeuseofCBCT.

Advantages:1. It minimises the cost of radiation

detectorsinconventionalCT.2. Itprovidesamorerapidacquisitionofthe

datasetoftheentirefieldofview(FOV).3. It involves a shorterexamination time,

better image sharpness, reduced imagedistortion,andincreasedx-rayefficiency.

Disadvantages:1. Imagenoiseandlow-contrastresolution

duetothedetectionofscatteredradiationare the biggest disadvantages of a largeFOV.

Compacthigh-qualitytwo-dimensional(2D)detectorarraysandtherefinementofapproximatecone-beamalgorithmshavemadetheuseofCBCTmoreacceptable.

CBCT Scanners CBCTscanners(19)usea2Dextendeddigitalarraywitha3Dx-raybeamandanareadetector

Table2:BoneQualityDensity Housefieldunits(CTnumbers)D1 1250D2 850–1250D3 350–850D4 150–350D5 <150

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based on volumetric tomography. The imageintensifier tube (IIT)–charge-coupled device inCBCT is well known for its use inmaxillofacialimaging.Recently,theuseofaflatpanelimager(FPI) has been employed, which consists of acesium iodide scintillator applied to a thin filmtransistormadeofamorphoussilicon.Thevariousadvantages associated with the use of FPI areimageswithlessernoiseandaninherentdetectorconfigurationthatreducesgeometricdistortions.CBCTimagingcanbeappliedtoplanningimplantplacement (20–22) as well as to assessing anypathologyforasurgicalprocedure(23–25),TMJ,andcraniofacialfractures(26–28). The CBCT software produces variousreal-time advanced image display techniques,includingobliqueplanarreformationandcurvedplanar reformation. To evaluate third molarimpactionsandTMJ,obliqueplanarreformationis used. Curved planar reformation helpstoprovide thin slice images of the dental archto access the bone morphology through serialtransplanar reformation, finding an associationofcriticalstructureswithimpactedthirdmolars,to evaluate TMJ and pathological conditionsaffectingthemaxillaandmandible.Thenumberofvoxelscanbeincreasedintheslidetothickenmulti-planar volume reformations. This helpsproduce an unmagnified and undistorted “raysum”imageofthepatient.

Software Applied to Oral Implantology Computer software, when used with CT orMRI,hasproven tobeofgreatvalue in implantdiagnosisandtreatmentplanning(29).Usingthesesoftwareprograms,near-original3D imagescanbeobtainedalongwiththeconstructionofsurgicaltemplates to transfer necessary information tothepatient’smouth.Generally, thisprocedureisbasedonstereolithographicmodels(30–31).A3DimageiscreatedbyprocessingtheCTdataintheDICOM3formatforaccuratetreatmentplanninginimplantplacement(32).Withtheuseofvariousprograms, such as Implametric®, SimPlant®(30–34), Nobel Guide® (35), med3D® (32),etc.,surgicaltemplatescanbemadeforselectiveimplant placement (33) Most programs showan axial cut and a panoramic cut withmultiplebuccolingual cuts (34). Essentially, computer-guided implantplanninghelps invisualisingtheanatomical structures in three spatial planes.Surgical navigation systems are currently abletooffer greater security of critical structures toobtain improved results (31). These systemsinclude RoboDent®, DenX IGI®, VISIT®,CADImplant®, LITORIM®, Virtual Implant®,

VectorVision®,etc.

Guided image planning Through guided planning, highly preciseimplant positioning can be obtained long withinformation regarding bone quantity for aminimally invasive surgery (36).Surgical guideshelp to transfer the diagnostic wax-up of therestorationintotheactualimplantplanning(37). Fourkindsoftemplatescanbeusedastoolswith CT during implant planning, includingvertical lead strip guides, circumference leadstrip guides, gutta-percha guides or guideswithasystemofdisks(38).Allguidesexceptverticalleadstripguidescanbeusedasbotharadiographand as a surgical template. When a study wascarriedoutusingCTaloneandCTwithtemplates,betterresultswereobtainedinthelatter(39).Toachieveamorefunctionalandaestheticoutcome,the template should not only be based on bonecharacteristicsbutalsoon thefinalshapeof thetooth(40).Withthehelpoftemplates,itiseasierto place implants during a one-step surgery,especially in areas of anatomic limitations (41)Notonlydoes it help in implantplacement, butit also allows for the visualisation of the bonein each area to choose the ideal donor site forosseous grafts (42). In addition, 3D planninghelps follow the critical anatomical structuresalong the implant trajectory whenplacing thetranszygomatic implants (43). According to astudy by Vrielink et al., (44), the accumulatedsuccessfortranszygomaticimplantswasfoundtobe92%duringafollow-upperiodof15months.

Guided Surgical Planning For the success of surgical intervention,the exact position of the instruments must beknown.CTorRemoteneuralMonitoring(RNM)images are used as maps to represent surgicalinstrumentsinrelationtopatientimages.Duringsurgery, this allows for the visualisation of theinstrumentposition45. Computer-assisted surgery not only helpsin implant placement, but it is also useful inarthroscopy of the TMJ, osteogenic distraction,biopsies, tumour treatment, deformities, andforeignbodyextirpation(45).Sensorsareattachedto the rotatory instruments, surgical templateand patient’s head cap. It is possible to see thereal situation through data obtained from thisnavigation(29).Theuseofstereotacticsystemsinneurosurgery led to thedevelopmentof systemsbased on ultrasounds and electromagneticsystems (46), as well as of optical navigationsystems based on infrared light (45–47). The

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accuracyofthissystemhasbeenprovenbyvariousstudies (47–49).Even though these systems aremorevividlyused,anewkindofsensorhasbeenintroduced,which is based on surface detectionbyalaserscanner. Theaccuracyofcomputer-guidednavigationiscontrolledbymanyfactors,suchasthetransferof data from planning to surgery, the surgeon’sability to interact with the system, not payingattentiontotheindicationsfromthemonitorandtechnicalfailures(50).Agoodcontroloverthesefactors puts computer-guided navigation abovemanual implantation. The only disadvantageassociatedwith this is the use of CT, leading togreaterradiationexposure.Toovercomethis,theuseofCBCThasbeenputforthbyvariousstudies(33,37,51) The various commercial systemsavailableareRoboDent®(52),DenXIGI®(53),CADImplant®,VISIT®,LITORIM®(54),VectorVision®,etc. A good treatmentplanwill help reduce thetotaltime,aswellassurgicalandpost-operativecomplications, while improving the aestheticsand final functional outcome. Although theapplicationofanavigationsystemhasresultedinbetterimplantplacement,thereisstillaneedformoreclinicalstudies(55). Conclusion

Conventional radiography is of littleimportance in implant imaging. Regardless,panoramicradiographyremainsthetechniqueofchoicedue to its cost effect.To access the exactlocationsofvitalstructures,MRIcanbeofhelp,butitissubjectedtoartefacts,geometricdistortionandareasofsignalloss.Itisbestusedwhenthedelineationofsofttissueisalsorequired.WiththeadventofCT,quantitativeandqualitativeanalysesofbonecanbeconductedforimplantplacement.Multi-slicehelicalCTpresentsagreateradvantageover conventional CT, as it rapidly covers anextended anatomic area with reduced patientmotion. With the advent of software used withCTorMRI,a3Dmodelcanbeobtainedandtheconstructionofasurgicaltemplateispossible. The recent technology used for dentalimplant imaging is CBCT, as it provides therapid acquisition of data with little radiationexposure. It generates images replicating thoseused in daily clinical practice. Therefore, due tothegreateradvantagesassociatedwithCBCToverothertechniques,itisthetechniqueofchoiceforimplantimaging.

Acknowledgement

We are very thankful to the authors in thereferencesmentioned.

Conflict of Interest

None.

Funds

None.

Authors’ Contributions

Conceptionanddesign,analysisandinterpretationofthedata:SG,NPDraftingofthearticle,collectionandassemblyofdata:SGFinalapprovalofthearticle:JS,NPProvisionofstudymaterialsorpatient,statisticalexpertise:JS

Correspondence

DrJitenderSolankiBDS,MDS(BhimRaoAmbedkarUniversity)DepartmentofPublicHealthDentistryVyasDentalCollege&HospitalPaliRoad,JodhpurRajasthanTel:91-9571580558Email:solankijitender@gmail.com

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