Case Report Implant-Supported Prosthetic Therapy of an Edentulous Patient: Clinical and Technical Aspects

Luca Ortensi 1,*, Marco Ortensi 2, Andrea Minghelli 3 and Francesco Grande 4

1 Department of , University of Catania, 95124 Catania, Italy 2 CDT Private Practice, 40126 Bologna, Italy; [email protected] 3 School of Dentistry, University of Bologna, 40126 Bologna, Italy; [email protected] 4 Oral and Maxillofacial Surgery, University of Bologna, 40126 Bologna, Italy; [email protected] * Correspondence: [email protected]

 Received: 20 May 2020; Accepted: 23 June 2020; Published: 1 July 2020 

Abstract: The purpose of this article is to show how to implement an implant-supported prosthetic overdenture using a digital workflow. Esthetic previewing using a specific software, guided-surgery, construction of the , and the esthetic finalization are described in this article. Patients suffering from severe loss of bone and soft tissue volume could benefit from the construction of an overdenture prosthesis as a feasible therapeutic choice for functional and esthetic issues of the patient.

Keywords: prosthesis; Digital Smile System; overdenture; digital prosthetic planning; atrophic patient

1. Introduction A pleasant appearance is ever more aspired to in the daily life of everyone, at any age. When adverse changes occur to a visible part of the body, the social and psychological impact can be negative for the individual [1]. Among the least well-tolerated changes is edentulism; which, in addition to causing significant functional deficits (chewing, phonetics), involves visible changes of facial esthetics, because with the loss of teeth and the resulting reabsorption of the alveolar crests, there is naturally less support for the soft tissues of the face, which takes on an unpleasant look, regardless of the person’s age. Although the total removable prosthetic is doable in a short timeframe and is economical and efficient, it is not easy to make to enhance the function and esthetics of the totally edentulous patient. These two aspects are certainly an advantage, but that is not enough to consider removable prosthesis for the ideal prosthetic therapy. In fact, not even this type of state-of-the-art prosthetic can completely restore chewing capacity and strength in some types of patients [2]. In elderly patients with atrophic maxilla, the implant-supported removable prosthesis (overdenture) is considered a feasible option in the prosthetic treatment plan [3]. When a severe loss of supporting bone structure has already happened, it would be necessary to optimize the soft tissues aspect of the lower third of the face, facilitating, at the same time, home oral hygiene procedures and patient comfort [4,5]. Stabilization of the removable prosthesis with a reduced number of implants may present multiple advantages. The biological and economic costs could be contained, the time for oral rehabilitation is shorter, and the long-term success rates are over 90%. In the mandible, two implants seem to be sufficient to obtain good stabilization of the removable prosthesis and the literature does not show statistically significant differences in terms of survival rate and comfort for the patient between insertion of two or four implants, solidified by a bar or with connections not constraining the implants (i.e., ball-attachment or other individual attachment type) [6]. On the other hand, for the upper maxilla the insertion of only two implants is not considered an ideal option if long cantilevers are expected; more predictable results could be achieved with the insertion of at least four implants connected by a metal or titanium

Prosthesis 2020, 2, 140–152; doi:10.3390/prosthesis2030013 www.mdpi.com/journal/prosthesis Prosthesis 2020, 1, FOR PEER REVIEW 2

Prosthesis 2020, 2 141 connected by a metal or titanium bar, considering also the shape of the maxillary arch [7]. In this specific therapy, the prosthesis could have a limited palate, improving the patient’s comfort and flavorbar, considering perception also [8]. the shape of the maxillary arch [7]. In this specific therapy, the prosthesis could haveHowever, a limited palate,the treatment improving plan the of atrophic patient’s patients comfort is and a challenging flavor perception procedure [8]. for the clinician and also theHowever, technician. the treatment Several factors plan of should atrophic be patientsconsidered is a challengingduring the treatment procedure planning for the clinician in order and to realizealso the an technician. appropriate Several oral rehabilitation. factors should be considered during the treatment planning in order to realizeRecently an appropriate modern oralprosthetics rehabilitation. makes use of digital technologies to support both the diagnostic and theRecently therapeutic modern phases prosthetics of patient makes rehabilitati use ofon, digital facilitating technologies also the to communication support both the between diagnostic the clinicianand the therapeutic and the lab phases[9–11]. of patient rehabilitation, facilitating also the communication between the clinicianTraditional and the removable lab [9–11]. prosthetics and those supported by implants have benefitted from these innovationsTraditional both removable in virtual prosthetics planning of and clinical those supportedcases and byas implantsa support have during benefitted the construction from these phaseinnovations [12–15]. both in virtual planning of clinical cases and as a support during the construction phaseThe [12 purpose–15]. of this article is to illustrate, through detailed step-by-step description of a complex clinicalThe case, purpose the construction of this article of is toan illustrate,inferior overdenture through detailed with step-by-stepimplant support, description applying of a complexthe new digitalclinical case,technologies the construction to every of an inferiorphase overdentureof the diagnostic with implant and support,prosthetic applying therapy, the newreducing digital implementationtechnologies to every time and phase analogical of the diagnostic phases. and prosthetic therapy, reducing implementation time and analogical phases. 2. Materials and Methods 2. Materials and Methods A 70-year old patient came to the dental office complaining of diminished masticatory capacity and lossA 70-year of retention old patient of both came removable to the dental dentur officees. complaining She wanted of to diminished improve her masticatory smile and capacity facial esthetics,and loss of stating retention she ofwas both dissatisfied removable with . the co Shelor wantedand poor to visibility improve herof her smile teeth, and no facial matter esthetics, how bigstating she shesmiled. was dissatisfiedThe patient with also theasked color to and avoid poor multiple-steps visibility of her therapies teeth, no and matter desired how to big have she smiled.a new prostheticThe patient solution also asked in the to avoidshorte multiple-stepsst time as possible. therapies The andpatient’s desired smile to haveseemed a new non-harmonious prosthetic solution due toin thedental shortest wear time and asthe possible. inclination The of patient’s the occlusal smile seemedplanes, non-harmoniouswhich affected her due general to dental appearance wear and (Figurethe inclination 1). The ofpatient the occlusal gave her planes, written which consent affected to herpublish general photos appearance of her clinical (Figure 1case,). The including patient photosgave her of writtenher face. consent to publish photos of her clinical case, including photos of her face.

FigureFigure 1. 1.Initial Initial state state of of the the face: face: a a reduction reduction of of the the vertical vertical dimension dimension is is observed observed with with an an increase increase in perilabial wrinkles. in perilabial wrinkles.

Her history did not show any pathology incompatible with dental treatment and demonstrated that sheshe waswas in in good good general general health health and classifiedand classified as ASA1. as ASA1. The facial The examination facial examination showed ashowed reduction a reductionof the vertical of the dimension, vertical dimension, with a widening with a of widening the nasolabial of the folds,nasolabial and diminished folds, and diminished tone of theperioral tone of thesoft perioral tissue, with soft atissue, generalized with a generalized deterioration deterior of all facialation estheticof all facial parameters esthetic (Figureparameters2). During (Figure the 2). Duringintraoral the clinical intraoral examination, clinical examination, incongruous incongruou prosthesiss in prosthesis both arches in both have arches been observed have been (Figure observed3). (Figure 3).

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Figure 2. Extraoral facial photos: lateral view. FigureFigureFigure 2. 2.2. Extraoral Extraoral facial facial photos: photos: laterallateral lateral viewview view...

Figure 3. Intraoral photos of the removable dentures. FigureFigureFigure 3. 3.3. Intraoral Intraoral photos photos of of the the the removable removable removable dentures.dentures. dentures. The upperupper arch arch had had a full-removable a full-removable denture, denture, while while the lower the jawlower had jaw a fixed had prosthesis a fixed supportedprosthesis TheThe upper upper arch arch had had a a full-removable full-removable denture,denture, whilewhile thethe lowerlower jaw had a fixed prosthesis bysupported few periodontally by few compromisedperiodontally teethcompromised as shown by t theeeth periapical as shown mandibular by the radiographs,periapical mandibular which also supportedsupported by by few few periodontallyperiodontally compromisedcompromised tteetheeth asas shownshown byby thethe periapical mandibular showradiographs, several periodontalwhich also pockets,show several different periodonta carious lesions,l pockets, and different bone resorption carious aroundlesions, theand natural bone radiographs,radiographs, which which also also show show severalseveral periodontaperiodontall pockets,pockets, differentdifferent cariouscarious lesions, andand bonebone abutmentsresorption around (Figure4 the). natural abutments (Figure 4). resorptionresorption around around the the natural natural abutments abutments (Figure (Figure 4). 4).

FigureFigure 4.4. EndoralEndoral periapical radiographs ofof mandibularmandibular teeth.teeth. FigureFigure 4. 4. EndoralEndoral periapical periapical radiographs radiographs of of mandibular mandibular teeth. teeth. DuringDuring the the firstfirstfirst visit, visit, severalseveral instrumentalinstrumental analyses were done, done, such such as as lateral lateral cephalometric cephalometric and and During the first visit, several instrumental analyses were done, such as lateral cephalometric and electromyography.electromyography. Lateral LateralLateral cephalometry cephalometrycephalometry is ais valuable a valuab diagnosticlele diagnosticdiagnostic tool thattooltool thethatthat authors thethe authorsauthors consider considerconsider pivotal electromyography. Lateral cephalometry is a valuable diagnostic tool that the authors consider forpivotalpivotal formulating for for formulating formulating a proper a treatmenta properproper treatmenttreatment plan in a complexplan in a prosthetic complex prosthetic rehabilitationprosthetic rehabilitationrehabilitation of an atrophic of of an an patient atrophic atrophic [16 ]. pivotal for formulating a proper treatment plan in a complex prosthetic rehabilitation of an atrophic Thispatientpatient x-ray [16]. [16]. examination This This x-ray x-ray examination enablesexamination the study enablesenables of thethe hardstudy and of the soft hardhard tissues andand of softsoft the tissues tissues patient’s of of the face;the patient’s patient’s in particular, face; face; patient [16]. This x-ray examination enables the study of the hard and soft tissues of the patient’s face; theinin particular, particular, relationship the thebetween relationship relationship the maxilla betweenbetween as thethe well maxilla as the as spatial well asas position thethe spatialspatial of the positionposition upper of of central the the upper upper incisor central central and in particular, the relationship between the maxilla as well as the spatial position of the upper central theincisorincisor philtrum. andand thethe It is philtrum.philtrum. also possible ItIt isis toalsoalso identify possiblepossible the to musculoskeletal identify thethe musculoskeletalmusculoskeletal classification with classificationclassification an appropriate with with andan an incisor and the philtrum. It is also possible to identify the musculoskeletal classification with an simpleappropriateappropriate cephalometric andand simplesimple analysis cephalometriccephalometric [17]. The study analysis of the [17]. patient’s The latero–lateralstudystudy ofof thethe radiography patient’spatient’s latero–laterallatero–lateral highlighted appropriate and simple cephalometric analysis [17]. The study of the patient’s latero–lateral meso-facialradiographyradiography musculoskeletal highlightedhighlighted meso-facialmeso-facial typology musculoskeletalmusculoskeletal with reduced occlusal typology risk. withwith Surface reducedreduced electromyography, occlusalocclusal risk. risk. Surface Surface using radiography highlighted meso-facial musculoskeletal typology with reduced occlusal risk. Surface electrodeselectromyography,electromyography, placed on usingusing the masticatory electrodeselectrodes muscles,placed on will the allow masticatory the clinician muscles,muscles, to evaluate willwill allowallow masticatory thethe clinician clinician activity to to electromyography, using electrodes placed on the masticatory muscles, will allow the clinician to andevaluateevaluate to understand masticatory masticatory whether activityactivity the andand occlusal toto understandunderstand load is adequate whether or the excessive occlusalocclusal [18 loadload]. A is measurementis adequateadequate or or ofexcessive excessive chewing evaluate masticatory activity and to understand whether the occlusal load is adequate or excessive loads[18].[18]. A producedA measurement measurement by the ofof patient chewingchewing is not loadsloads a secondary producedproduced element; by the patientpatient on the is contraryis notnot aa secondarysecondary it represents element; element; an important on on the the [18]. A measurement of chewing loads produced by the patient is not a secondary element; on the contrarycontrary itit representsrepresents anan importantimportant aspect of comparison forfor thethe wholewhole workingworking group,group, andand in in contrary it represents an important aspect of comparison for the whole working group, and in

Prosthesis 2020, 2 143 Prosthesis 2020, 1, FOR PEER REVIEW 4 particularaspect of comparison with the dental for the technician whole working who will group, have and to intake particular into consideration with the dental the technicianextent of these who willvalues have during to take the into design consideration and construction the extent of the of theseprosthesis. values during the design and construction of the prosthesis.In the first appointment two photos were taken of the patient’s face according to a coded techniqueIn the for first the appointment DSS (Digital two Smile photos System, were taken Bologna, of the Italy) patient’s software face according [19]. It is to important a coded technique to take photosfor the DSSof the (Digital face keeping Smile System,the patient Bologna, in a position Italy) software that is stable [19]. and It is repeatable important over to take time, photos trying of not the toface change keeping the the enlargement patient in a positionratio between that is stableshots. and For repeatable this purpose, over time,the tryingpatient not is toasked change to thesit comfortablyenlargement keeping ratio between her back shots. straight For this while purpose, the oper theator patient used is a asked camera to sitset comfortably on a tripod keepingto stabilize her itsback position straight in while relation the operatorto the patient used abeing camera photog set onraphed. a tripod The to stabilizesubject had its positionto be positioned in relation so to that the patienttheir Frankfurt being photographed. Plane (the line Thethat subjectjoins the had Porion to be and positioned the Orbital sothat Point) their was Frankfurt parallel to Plane the horizon. (the line Oncethat joins the thespatial Porion position and the of Orbital the head Point) is identified, was parallel it tomust the horizon.remain unchanged Once the spatial with positionrespect to of the camera-tripodhead is identified, complex. it must The remain patient unchanged may wear with dedic respectated to glasses the camera-tripod used to calibrate complex. the digital The patient pre- renderingmay wear software dedicated (DSS; glasses Figure used 5). to calibrate the digital pre-rendering software (DSS; Figure5).

FigureFigure 5. The5. The first first facial facial photo photo was was taken taken asking asking the patientthe patient to smile to smile and showand show as many as many teeth asteeth possible as and the secondpossible facial photographand the second was facial taken photograph with cheek was retractors. taken with cheek retractors.

The glasses represent a true measuring system that differentiates differentiates this software from other similar systems. Thanks to their their shape shape and and the the presence presence of calibration calibration markers used as a reference, reference, the glasses facilitate maintenance of the perpendicular position of the patientpatient andand thethe camera.camera. The first first facial photo was taken asking the patient to smile and show as muchmuch teethteeth asas possible.possible. The second facial photograph was taken with cheek retractors toto betterbetter highlighthighlight thethe teethteeth ofof thethe patient.patient. The photographic status status is is completed with with the the pr profileofile shots of her face and with the intraoralintraoral photographs that allow us to make further diagnostic assessments regarding the overall esthetics of her face and its physiognomic characte characteristicsristics on on which which we we can can proceed proceed with with our our prosthetic therapy therapy [20]. [20]. After this phase, the two extraoral photos taken duri duringng the first first visit were inserted in a dedicated 2D software (Digital Smile System, Bologna, Italy) useful forfor thethe finalfinal estheticesthetic ofof thethe patient.patient. The Digital Smile System approach using digital techniques for the esthetic preview was only considered a tool for communication with the patient and for the entire dental team. DSS not only allowed the patient to see the esthetic esthetic future appear appearance,ance, but it also also enabled enabled production production of a prototype prototype for the functional check of the digital project carried out [21]. The fact that the patient can see the possible future esthetic results through digital rendering, including the possibility of changes if desired, reduces overall clinical practice time. The procedure requires that the photographs taken be

Prosthesis 2020, 2 144 for the functional check of the digital project carried out [21]. The fact that the patient can see the possible future esthetic results through digital rendering, including the possibility of changes if Prosthesis 2020, 1, FOR PEER REVIEW 5 desired, reduces overall clinical practice time. The procedure requires that the photographs taken be importedimported into intothe the DSSDSS andand then an esthetic esthetic previe previeww of ofthe the future future prosthetic prosthetic therapy therapy is developed is developed (Figure(Figure6), which 6), which consists consists of a virtual of a virtual arrangement arrangem ofent commercial of commercial teeth teeth present present in the in software the software database. The databasedatabase. consistsThe database of upper consists and of lowerupper and teeth lower of various teeth ofshapes various andshapes sizes. and Anteriorsizes. Anterior and posteriorand teethposterior are positionedProsthesis teeth 2020 are, 1 using, FOR positioned PEER the REVIEW occlusal using the rim, occlusal previously rim, previously suitably adaptedsuitably adapted in the oral in the cavity oral 5cavity as a guide. Teethas are a guide. chosen Teeth according are chosen to according esthetic and to esthetic functional and functional parameters parameters and can and be can replaced be replaced with with others of othersimported of different into theshape DSS or and color, then if an necessary. esthetic previe Thisw allows of the usfuture to showprosthetic the patienttherapy theis developed possible final different shape(Figure or 6), color, which if consists necessary. of a Thisvirtual allows arrangem us toent show of commercial the patient teeth the present possible in the final software esthetic so that esthetic so that she can participate in the therapeutic project in collaboration with the whole clinical– she can participatedatabase. The in database the therapeutic consists of project upper and in lower collaboration teeth of various with shapes the whole and sizes. clinical–technical Anterior and team. technical team. posterior teeth are positioned using the occlusal rim, previously suitably adapted in the oral cavity as a guide. Teeth are chosen according to esthetic and functional parameters and can be replaced with others of different shape or color, if necessary. This allows us to show the patient the possible final esthetic so that she can participate in the therapeutic project in collaboration with the whole clinical– technical team.

Figure 6. Digital preview of the final esthetic in the DSS software (2D). Figure 6. Digital preview of the final esthetic in the DSS software (2D). In a dedicated appointment,Figure 6. Digital previewall the ofcompromised the final esthetic indental the DSS elements software (2D). in the lower arch were In a dedicated appointment, all the compromised dental elements in the lower arch were extracted except the lateral incisor which serves as a provisional anchor of the new provisional lower extracted exceptIn a the dedicated lateral appointment, incisor which all servesthe compromised as a provisional dental elements anchor in of the the lower new arch provisional were lower denture (Figure 7). denture (Figureextracted7). except the lateral incisor which serves as a provisional anchor of the new provisional lower denture (Figure 7).

Figure 7.FigureUse 7. of Use lateral of lateral incisor incisor as as a a provisional provisional anchor anchor for forthe provisional the provisional denture. denture. Figure 7. Use of lateral incisor as a provisional anchor for the provisional denture.

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ProsthesisAfter 2020 tissue, 1, FOR healing, PEER REVIEW preliminary impressions of the soft tissue and edentulous arches were made.6 The authors did not use an intraoral scanner (IOS) because there is no consensus in the literature regardingAfter real tissue effi cacyhealing, in edentulous preliminary subjects impressions [22]. We of usuallythe soft use tissue a high-precision and edentulous alginate arches with were long settingmade. timeThe usefulauthors for did tissue not functionalization use an intraoral applied scanne inr (IOS) two stages, because where there possible is no consensus (only in edentulous in the subjects):literature regarding a first impression real efficacy is made in edentulous with the subj alginateects [22]. mixed We usually with a highuse a consistencyhigh-precision (Neocolloid, alginate Zhermack,with long setting Badia time Polesine, useful Ro, for Italy), tissue itfunctional is then driedization and applied modified in two by stages, removing where the possible undercut (only parts within edentulous a sharp tool subjects): and relined a first with impression the same is made material with but the in alginate a more fluidmixed form with to a readhigh allconsistency the details of(Neocolloid, the anatomical Zhermack, tissues. Badia The modelPolesine, obtained Ro, Italy), is scanned it is then with dried a laboratory and modified scanner by removing (Sinergia the Scan, Nobilundercut Metal, parts Asti, with Italy) a sharp and tool a resin and relined with base the issame built material on it by but sending in a more a dedicated fluid form fileto read to the 3Dall printerthe details (Asiga of the MaxUV, anatomical Australia), tissues. coating The model it with obtained wax for is registration scanned with of the a laboratory centric relationship, scanner esthetic,(Sinergia functional Scan, Nobil determinants, Metal, Asti, Italy) and verticaland a resin dimension occlusion [23 base]. is built on it by sending a dedicated file toIt isthe important 3D printer in (Asiga the upper MaxUV, occlusal Australia), rim, during coating functionalization it with wax for registration in the oral cavity,of the centric to mark somerelationship, landmarks; esthetic, the functional midline, the determinants, canine line, and and vertical the smile dimension line. These [23]. reference lines will serve in theIt alignment is important phase in the of upper the occlusal occlusal rims rim, in during the 3D functionalization software (Exocad in software,the oral cavity, Exocad to mark GmbH, Darmstadt,some landmarks; Germany). the midline, the canine line, and the smile line. These reference lines will serve in the alignment phase of the occlusal rims in the 3D software (Exocad software, Exocad GmbH). Transfer of Data from the Dental Office to the Laboratory Transfer of Data from the Dental Office to the Laboratory Once the virtual teeth arrangement was obtained—and approved by the patient—the file containing the patient’sOnce the information, virtual teeth the arrangement photographic was alignments, obtained—and the libraries approved chosen, by the and patient—the the work process file wascontaining transferred the patient’s to the dental information, technician the photograph laboratoryic where alignments, the file the was libraries imported chosen, into and a 3D the software work programprocess was (Exocad transferred® software, to the Exocad dental GmbH). technician The la informationboratory where file the exported file was from imported DSS consisted into a 3D of a ® PDFsoftware format program and individual (Exocad photographs software, Exocad of the patient’s GmbH). face The with information a customized file exported two-dimensional from DSS (2D) consisted of a PDF format and individual photographs of the patient’s face with a customized two- virtual smile design. dimensional (2D) virtual smile design. The files from DSS were then superimposed onto scanned images of the denture. The dental The files from DSS were then superimposed onto scanned images of the denture. The dental technician used the outline of the virtual smile obtained to place a tooth from the library or to create technician used the outline of the virtual smile obtained to place a tooth from the library or to create customized teeth with tools from Freeform (Exocad® software, Exocad GmbH) to convert the virtual customized teeth with tools from Freeform (Exocad® software, Exocad GmbH) to convert the virtual 2D teeth arrangement into a 3D teeth arrangement [24]. 2D teeth arrangement into a 3D teeth arrangement [24]. Simply put, “coupling” of the data, thinking that the final image of the mounting, obtained Simply put, “coupling” of the data, thinking that the final image of the mounting, obtained in in the 2D version, represents a face of the volumetric solid corresponding to what is in the 3D the 2D version, represents a face of the volumetric solid corresponding to what is in the 3D version version (Figure8). (Figure 8).

FigureFigure 8. Overlap 8. Overlap of the of 2Dthe image2D image of the of patient’sthe patient’s face fa withce with the the 3D 3D digital digital model model inside inside a 3D a 3D software. The 2D teeth representsoftware. the anteriorThe 2D teeth face ofrepresent the 3D solid.the anterior face of the 3D solid.

TheThe teethteeth usedused from the 3D database represent represent th thee volume volume of of the the solid, solid, and and the the 2D 2D teeth teeth are are the the anterioranterior faceface ofof thisthis solid.solid. The dental dental technician technician completes completes the the 3D 3D phase, phase, improving improving the the occlusal occlusal ratio ratio betweenbetween thethe archesarches (according to the literature) literature) and and producing producing the the prosthetic prosthetic base base that that will will sustain sustain thethe dental dental elements.elements. After this this phase, phase, CAD CAD (Com (Computer-Aidedputer-Aided Design) Design) work work can can produce produce a prototype a prototype that corresponds entirely to the project made with DSS and processed in a 3D environment. The file obtained is sent to a 3D printer (Asiga MaxUV, Australia) and transformed into a prototype to be tested in the oral cavity, verifying the intraoral adaptation, the cranio–mandibular ratio, the esthetics

Prosthesis 2020, 2 146 that corresponds entirely to the project made with DSS and processed in a 3D environment. The file obtained is sent to a 3D printer (Asiga MaxUV, Australia) and transformed into a prototype to be tested inProsthesis the oral 2020 cavity,, 1, FOR verifying PEER REVIEW the intraoral adaptation, the cranio–mandibular ratio, the esthetics of the7 smile and face. These prototypes represent the final volume of the final prosthesis. The clinician can of the smile and face. These prototypes represent the final volume of the final prosthesis. The clinician make changes without impacting the protocol, in the prototypes, thus modified, can be scanned again can make changes without impacting the protocol, in the prototypes, thus modified, can be scanned by the technician, and overlapped digitally to the original project. again by the technician, and overlapped digitally to the original project. SubsequentlySubsequently thethe prototypeprototype isis usedused as a radiologicalradiological stent with which which the the CBCT(cone CBCT(cone beam beam computedcomputed tomography) tomography ) is is done, done, usingusing aa dedicateddedicated device (Evobite (Evobite with with 3D 3D marker, marker, 3Diemme, 3Diemme, Italy), Italy), whichwhich was was adapted adapted toto thethe itemitem withwith radiotransparentradiotransparent silicon (Elite (Elite Glass, Glass, Zhermack, Zhermack, Badia Badia Polesine, Polesine, Ro,Ro, Italy; Italy; Figure Figure9 ).9).

FigureFigure 9. 9.The The prototype prototype used used as as aa radiologicalradiological stent during during the the conduct conduct of ofthe the CBCT CBCT (cone (cone beam beam computed tomography). computed tomography).

TheThe DicomDicom datadata resultingresulting fromfrom thethe X-rayX-ray and the STL (Standard Triangulation Triangulation Language) Language) files files relativerelative to to the the anatomical anatomical and and prosthetic prosthetic parts parts obtained obtained from from theintraoral the intraoral scan arescan imported are imported in a specific in a implantspecific planningimplant planning software software (Realguide (Realguide 5.0, 3Diemme, 5.0, 3Diemme, Italy) where, Italy) thanks where, to thanks a dedicated to a dedicated algorithm, theyalgorithm, are overlapped they are usingoverlapped a replicable using a and replicable controlled and procedure. controlled Throughprocedure. use Through of the implant use of the line databaseimplant line (Thommen database Medical (Thommen AG, Medical Grenchen, AG, Switzerland), Grenchen, Switzerland), the number the and number position and of theposition implant of screwsthe implant to beinserted screws viato be guided inserted surgery via guided are planned. surgery After are careful planned. functional After careful and esthetic functional evaluation and andesthetic final verification,evaluation and the prosthetic-drivenfinal verification, planthe wasprosthetic-driven approved, and plan a stereolithographic was approved, surgicaland a templatestereolithographic was made surgical using a template newer rapid was prototypingmade using technologya newer rapid (New prototyping Ancorvis, technology Bargellino, (New Italy). SubsequentlyAncorvis, Bargellino, two prosthetic-driven Italy). Subsequently implants two prosthetic-driven with a diameter implants of 4.0 mm with and a diameter a length of 4.0 9.5 mm mm ® ® (SPIand® a lengthCONTACT of 9.5 RCmm INICELL (SPI CONTACT®, Thommen RC INICELL Medical, AG) Thommen were placed, Medical with AG) awere dedicated placed, burr with kita (Thommendedicated burr Medical kit (Thommen Guided Surgery Medical Kit), Guided in the Surgery lower jaw,Kit), takingin the lower into account jaw, taking the boneinto account quality the and quantity,bone quality soft-tissue and quantity, thickness, soft-tissue anatomical thickness, landmarks, anatomical and the landmarks, type, volume, and the and type, shape volume, of the and final restoration.shape of the The final lateral restoration. incisor The that lateral acts as incisor provisional that acts anchor as provisional for the lower anchor denture, for the in lower this phase denture, was maintainedin this phase in was the mouthmaintained of the in patient the mouth for the of timethe patient necessary for the for implanttime necessary loading. for Healing implant screws loading. are Healing screws are positioned directly post-surgically, and the prosthesis is readapted with resilient positioned directly post-surgically, and the prosthesis is readapted with resilient material (Coe-Soft™ material (Coe-Soft™ GC America Inc., Alsip, IL, USA). GC America Inc., Alsip, IL, USA). About four weeks later [25], after tissue healing, with a dedicated tool (Cuff Height Measuring About four weeks later [25], after tissue healing, with a dedicated tool (Cuff Height Measuring Tool, Rhein 83, Bologna, Italy), measurements of the transmucosal paths were performed and the Tool, Rhein 83, Bologna, Italy), measurements of the transmucosal paths were performed and the most most suitable retention systems means were chosen (OT Equator, Rhein 83, Bologna, Italy; Figure 10) suitable retention systems means were chosen (OT Equator, Rhein 83, Bologna, Italy; Figure 10) and and were screwed to the implant fixtures with a preset force, with the corresponding retentive copings. The provisional prosthesis is readapted to make it suitable to receive the stainless-steel retentive cap housing nylon retentive inserts, improving the stability and hold. The general rule to apply for the choice of this type of attachments is the retentive part, which must extend beyond the transmucosal path by at least one millimeter [26].

Prosthesis 2020, 2 147 were screwed to the implant fixtures with a preset force, with the corresponding retentive copings. The provisional prosthesis is readapted to make it suitable to receive the stainless-steel retentive cap housing nylon retentive inserts, improving the stability and hold. The general rule to apply for the choice of this type of attachments is the retentive part, which must extend beyond the transmucosal path by at least one millimeter [26]. Prosthesis 2020, 1, FOR PEER REVIEW 8

Prosthesis 2020, 1, FOR PEER REVIEW 8

FigureFigure 10. Equator 10. Equator attachments attachments used used to to improveimprove the the stability stability and and retention retention of prosthesis. of prosthesis.

Thereafter the dental technician, using a 3D software (Exocad®, Exocad GmbH), plans the Thereafter the dental technician, using a 3D software (Exocad®, Exocad GmbH), plans the counter-barFigure [27], 10. inserting Equator retentiveattachments pins used into to improve the project the stability for the and mechanical retention ofhold prosthesis. of the teeth and counter-barpreparing [27], the inserting area of the retentive OT Equator pins attachment into the components project for (Rhein the mechanical83, Bologna, Italy). hold of the teeth and Thereafter the dental technician, using a 3D software (Exocad®, Exocad GmbH), plans the preparingThe the project area is ofsent the to OTthe Equatormilling center attachment (New Anco componentsrvis, Bologna, (Rhein Italia) indicating 83, Bologna, the type Italy). of metal counter-bar [27], inserting retentive pins into the project for the mechanical hold of the teeth and Theto projectbe used and is sent the type to the of construction milling center (laser (New melting Ancorvis, technology). Bologna, After being Italia) checked indicating in the dental the type of preparing the area of the OT Equator attachment components (Rhein 83, Bologna, Italy). laboratory and sent to for clinical testing, the precision and passivity of the piece is checked. metal toThe be project used andis sent the to typethe milling of construction center (New (laserAncorvis, melting Bologna, technology). Italia) indicating After the being type of checked metal in the The commercial teeth are then mounted, taking advantage of the prototype as a positioning guide. dental laboratoryto be used and and the senttype toof construction dentist for (laser clinical melting testing, technology). the precision After being and checked passivity in the of dental the piece is The perfectly polished prostheses are sent to the dental office (Figures 11–13), making sure there are checked.laboratory The commercial and sent to teeth dentist are for then clinical mounted, testing, the taking precision advantage and passivity of the of prototype the piece isas checked. a positioning no compression areas on the soft tissues. The patient is provided guidelines for prosthesis hygiene The commercial teeth are then mounted, taking advantage of the prototype as a positioning guide. guide. Themaintenance perfectly procedures. polished prostheses are sent to the dental office (Figures 11–13), making sure there are no compressionThe perfectly polished areas on prostheses the soft tissues.are sent to The the patientdental office is provided (Figures 11–13), guidelines making for sure prosthesis there are hygiene no compression areas on the soft tissues. The patient is provided guidelines for prosthesis hygiene maintenance procedures. maintenance procedures.

Figure 11. Details of the finished prosthesis.

FigureFigure 11. 11.Details Details ofof the fini finishedshed prosthesis. prosthesis.

Prosthesis 2020, 2 148

Prosthesis 2020, 1, FOR PEER REVIEW 9

Prosthesis 2020, 1, FOR PEER REVIEW 9 Prosthesis 2020, 1, FOR PEER REVIEW 9

Figure 12. Completed dentures ready to be sent to the dental office. Figure 12. Completed dentures ready to be sent to the dental office. Figure 12. Completed dentures ready to be sent to the dental office. Figure 12. Completed dentures ready to be sent to the dental office.

Figure 13. Postoperative intraoral view showing the good esthetic integration. Figure 13. Postoperative intraoral view showing the good esthetic integration. Figure 13. Postoperative intraoral view showing the good esthetic integration. Once the prosthetic therapy was completed, the patient’s face improved greatly from an esthetic Once theOnceviewpoint prosthetic the prosthetic (FigureFigure therapy 14). 13. therapy PostoperativeThe wassoft wastissue completed, completed,intraoral of the face view lo thetheoked showin pa patient’s firmtient’sg the and facegood toned. face improved esthetic A improved reduction integration greatly could greatly .from be seen an esthetic fromin an esthetic the nasolabial folds and perilabial wrinkles (Figure 15), both frontally and laterally. The vertical viewpointviewpoint (Figure (Figure14). The 14). softThe soft tissue tissue of of the the faceface lo lookedoked firm firm and andtoned. toned. A reduction A reduction could be seen could in be seen dimension,Once the prostheticwhich was therapyslightly increased,was completed, appeared the adequate patient’s and face well-tolerated improved greatly esthetically. from Duringan esthetic in the nasolabialthe nasolabial folds folds and and perilabial perilabial wrinkles wrinkles (Figur (Figuree 15), 15 both), both frontally frontally and laterally. and laterally. The vertical The vertical viewpointphonation (Figure and smiling14). The dynamics soft tissue the of patientthe face displayed looked firm natural and toned.looking A teeth reduction that were could perfectly be seen in dimension,dimension, whichintegrated was which with slightly was his faceslightly increased,(Figure increased, 16). appeared appeared adequate and and well-tolerated well-tolerated esthetically. esthetically. During During phonationthe nasolabial and foldssmiling and dynamics perilabial the wrinkles patient (Figur displayede 15), naturalboth frontally looking and teeth laterally. that were The perfectlyvertical dimension, which was slightly increased, appeared adequate and well-tolerated esthetically. During phonationintegrated and smiling with his dynamics face (Figure the16). patient displayed natural looking teeth that were perfectly integrated withphonation his faceand smiling (Figure dynamics 16). the patient displayed natural looking teeth that were perfectly integrated with his face (Figure 16).

Figure 14. Patient’s final smile with proper teeth position.

Figure 14. Patient’s final smile with proper teeth position. Figure 14. Patient’s final smile with proper teeth position. Prosthesis 2020, 1, FORFigure PEER REVIEW 14. Patient’s final smile with proper teeth position. 10

Figure 15.FigurePatient’s 15. Patient’s face face in in lateral lateral view:view: the the lip lipsupport support appears appears correct. correct.

Figure 16. Patient’s face at the end of the therapy: notice a reduction in the nasolabial folds and perilabial wrinkles.

3. Discussion During the prosthetic therapy, for both fixed and removable prostheses, communication with the patient is a vital part of the treatment. Effective digital previewing is the ideal way to explain esthetic changes to a patient and to receive their approval. Until now, many digital previewing methods have been used in dentistry solely for this purpose. The authors deem that digital previewing of the smile must be inserted into a more complex workflow [28]. In this article, the Digital Smile System approach was introduced into a complex digital workflow. DSS (Digital Smile System, Bologna, Italy) not only allowed the patient to see their future appearance, but it also enabled production of a prototype for the functional check of the digital project carried out. The fact that the patient can see the possible future esthetic results through digital rendering, including the possibility of changes if desired, reduces overall clinical practice time. Additionally, the construction of a prototype, based on the virtual assembly, minimizes the number

Prosthesis 2020, 1, FOR PEER REVIEW 10

Prosthesis 2020, 2 149 Figure 15. Patient’s face in lateral view: the lip support appears correct.

FigureFigure 16.16. Patient’sPatient’s face at the end of the therapy: no noticetice a a reduction reduction in in the the nasolabial nasolabial folds folds and and perilabialperilabial wrinkles. wrinkles.

3.3. DiscussionDiscussion DuringDuring the the prosthetic prosthetic therapy, therapy, for for both both fixed fixe andd and removable removable prostheses, prostheses, communication communication with with the patientthe patient is a vital is a partvital ofpart the of treatment. the treatment. Effective Effective digital digital previewing previewing is the idealis the way ideal to way explain to explain esthetic changesesthetic tochanges a patient to anda patient to receive and theirto receive approval. their Until approval. now, many Until digitalnow, many previewing digital methods previewing have beenmethods used inhave dentistry been used solely in for dentistry this purpose. solely The for authors this purpose. deem that The digital authors previewing deem that of the digital smile mustpreviewing be inserted of the into smile a more must complex be inserted workflow into a more [28]. complex workflow [28]. InIn this this article, article, the the Digital Digital Smile Smile System System approach approach was introduced was introduced into a complexinto a complex digital workflow. digital DSSworkflow. (Digital DSS Smile (Digital System, Smile Bologna, System, Italy) Bologna, not only Italy) allowed not only the allowed patient tothe see patient their to future see their appearance, future butappearance, it also enabled but it also production enabled production of a prototype of a prot for theotype functional for the functional check of check the digital of the projectdigital project carried out.carried The out. fact The that fact the patientthat the can patient see the can possible see the futurepossible esthetic future results esthetic through results digital through rendering, digital includingrendering, the including possibility the of possibility changes ifof desired, changes reduces if desired, overall reduces clinical overall practice clinical time. practice Additionally, time. theAdditionally, construction the of construction a prototype, of baseda prototype, on the ba virtualsed on assembly, the virtual minimizes assembly, theminimizes number the of number errors in the manufacture of the final product and becomes a fundamental instrument for prosthetic-driven surgery. The decision-making process of using an implant overdenture prosthesis or a Toronto or hybrid prosthetic devices depends on different factors. The selection and extent of artificial tissues are related to facial support, emergence profile of the artificial tooth, the tooth angulation and the use of full flange extension is mentioned for esthetic advantages. However, the application of gingival prostheses may be limited to certain clinical situations where oral hygiene is manageable, function proper and esthetics acceptable. With a removable design, a larger volume of tissue can be replaced, and proper cleaning is still feasible. An instrument that could suggest a correct therapeutic choice is the latero–lateral radiography of the patient, which provides some important parameters: acrylic flange height, mucosal coverage, -Implant distance, and buccal prosthesis profile [16]. According to Avrampou et al., when the mucosal coverage is less than 5 mm and the prosthetic profile is up to 30 degrees, a fixed prosthesis whit hybrid or crown design can be selected. On the other hand, when the mucosal coverage is more than 5 mm and the prosthetic profile is less than 30 degrees, a removable prosthesis with a buccal flange is advised. The use of overdenture involves different advantages. Compared to complete removable dentures, implant supported dentures have better stability and retention, improving function, esthetic, and satisfaction for the patient [29,30]. Furthermore, some data indicate that after receiving implants, Prosthesis 2020, 2 150 patients with overdenture eat a diet with more fiber and hard foods than with conventional dentures, even if this does not improve nutritional intakes of essential micronutrients and macronutrients [31]. Furthermore, phonetic problems have been reported more often with fixed prostheses than with overdentures, probably because impaired phonetics appears to depend also on the palatal design of the prosthesis [32,33]. Use of the prototype as a radiological stent during the examination of the CBCT, and its transformation into a surgery-driven guide make it possible to position implants according to the digital study done with the DSS and approved by the patient. Some phases of the described workflow require a learning curve by the clinical operator and technician. For example, the photos taken by the clinician for the DSS, must be taken in the exact manner as previously described to facilitate superimposing of the photo of the patient’s face, with the scan of the model and the old denture. Another important stage is ensuring the teeth from the database of the 3D software are matched with the outlines obtained by digital previewing with the DSS. In this case, if the match is not precise, the prototype will not correspond perfectly with that approved by the patient [34].

4. Conclusions The use of digital technologies is now vastly widespread in the field of dentistry and, in particular, in prosthetic therapy. In removable, traditional, and implant-supported prosthetic therapy, digital technology can play an essential role. The clinical case described was almost entirely done with an innovative digital workflow, both from clinical and technical viewpoints. In particular, guided surgery came into the digital workflow through a simplified approach that was closely dependent on the patient’s esthetics and functional aspects. The human component is still fundamental and not all stages can be carried out digitally. However, it is expected that technical developments will rapidly lead to more and more digitalized therapies with an increase in the end quality of the therapy and less conditioned by the skills of the individual operator.

Author Contributions: Conceptualization, L.O.; methodology, L.O. and M.O.; software, L.O. and M.O.; resources, L.O.; data curation, F.G. and A.M.; writing—original draft preparation, L.O. and A.M.; writing—review and editing, L.O. and A.M.; visualization, L.O.; supervision, F.G.; M.O. fabricated the prosthesis. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Acknowledgments: The authors thank Gianni Ortensi, Marco Ortensi, and Cesare Chiarini, who fabricated the prosthesis and supported laboratory digital processes. Conflicts of Interest: The authors declare no conflict of interest.

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