Received: 1 December 2020 Accepted: 5 January 2021

DOI: 10.1111/jerd.12711

CLINICAL ARTICLE

A digital approach to robust and esthetic implant overdenture

construction

Christopher Duhn DDS, MS1 | Ghadeer Thalji DDS, PhD1 |

Sandra Al-Tarwaneh DDS, MS1 | Lyndon F. Cooper DDS, PhD2

1
Restorative Dentistry, University of Illinois at
Chicago, College of Dentistry, Chicago, Abstarct
Illinios, USA Objective: Overdenture therapy is an important option for implant rehabilitation.
2
Associate Dean for Research, University of
However, numerous reports suggest that mechanical/technical complications and
Illinois at Chicago, College of Dentistry,
Chicago, Illinios, USA failures can limit therapeutic success. The goal of this report is to illustrate a digital
approach to design and construction of a robust overdenture with high-esthetic
Correspondence
Lyndon F. Cooper, UIC College of Dentistry, value.
801 S. Paulina St. #402e, Chicago, IL 60612,
Materials and methods: Beginning with new denture design to establish esthetic
USA.
Email: cooperlf@uic.edu parameters, 3D modeling of a metal framework and the denture teeth are completed
in a connected manner. This enables connection of rapidly printed, prototype denti-
tion that is attached directly to the framework without intervening wax or acrylic
components. Following evaluation of the dentition and required adjustments, the
final dentition is milled from resin and processed to the selective laser sintered
framework.
Results: The advantages of the digital workflow include the control of dimensions
and strength of the framework, the esthetic relationship of the framework to the
dentition and the facilitation of esthetic try-in of the dentition.
Conclusion: Enhancing a robust overdenture can be readily achieved using a digital
workflow.
Clinical significance: The use of digital technology enables the clinical team to plan
and produce prostheses with dimensions and contours that support long-term func-
tion and esthetics. The clinical chair time can be potentially reduced by use of digital
design that facilitates try-in and reduces major errors by improved communication
between the patient, dentist, and technician.

KEYWORDS
cobalt chromium, complications, digital dentistry, esthetics, overdenture

1 | I N T RO DU CT I O N dentures and prostheses. All have advantages and disadvantages that

span the biologic, prosthetic, psychological, and financial issues. Den-
Comprehensive oral rehabilitation of the edentulous patient presents tures are accepted by a discrete subset of the edentulous population
diverse biologic, prosthetic, psychological, and financial challenges to as effective tooth replacements.1 However, the use of dentures is
patients and clinicians. The various modes of rehabilitation range from associated with oral co-morbidities that include mucositis and contin-
complete denture therapy to mandibular implant overdentures to uous residual ridge resorption.2,3 The mandibular overdenture has
maxillary and mandibular overdentures to implant supported fixed been identified as a minimal therapeutic option for the edentulous

118 © 2021 Wiley Periodicals LLC wileyonlinelibrary.com/journal/jerd J Esthet Restor Dent. 2021;33:118–126.
DUHN ET AL. 119

patient and quality of life studies support the concept that broad 1.1 | Patient presentation
social benefits are accrued to the mandibular overdenture wearing
edentulous patient.4 In addition to prosthetic complications,5 contin- A 67 year old, African American male patient presented to the clinic
ued residual ridge resorption is reported and may require reline proce- with a maxillary overdenture with multiple, comminuted tooth and
dures.6 The use of maxillary overdentures has been less widely flange fractures. He presented with no co-morbidities that prevented
investigated; however, recent studies indicate that either four or six conventional dental therapy. His request was to repair the prostheses.
implant supported bar overdentures provide high success and satis- Clinical examination revealed no significant intraoral findings including
faction.7,8 A more simplified approach using four unsplinted maxillary the absence of denture stomatitis or denture related ulcerations.
implants to retain maxillary overdentures was associated with high Extraoral evaluation of the existing prosthesis demonstrated the mid-
mid-term implant survival and high-patient satisfaction, unless oppos- line was inconsistent with the facial midline, there was inappropriate
ing a conventional removable partial denture. Denture stomatitis was tooth display (no lower tooth display in a 67 old male), and potential
among the more common biologic complications and common pros- reduced vertical dimension of occlusion (VDO) based on facial
thetic complications involve replacement of resilient attachments and esthetics and large discrepancy between VDO and vertical dimension
repair of fractured teeth.9 The fourth alternative, restoring the denti- of rest (Figure 1(A)). Examination for the maxillary and mandibular
tion of edentulous individuals using implant supported fixed dentures overdentures revealed multiple fractures of the maxillary overdenture
or prostheses, is also reported to provide high-patient satisfaction and acrylic and evidence of previous repairs (Figure 2(A)). The mandibular
can be associated with mid- to long-term implant survival.10,11 More overdenture was intact, but occlusal wear was evident (Figure 2(B)).
recent studies indicate that both peri-implantitis and prothesis compli- Both the maxillary and mandibular overdentures included cast cobalt
cations increase over time for the implant supported fixed dentures, chrome frameworks as reinforcements to the acrylic. The maxillary
especially after 10 years.12 framework of “horseshoe” design lacked buccal support for the
When financial matters are of concern and patients seek implant flanges and the major connector was undersized thus questioning
support and retention of their prostheses, the implant overdenture offers rigidity and reciprocation. Moreover, restorative space available was
clear advantages. The comprehensive therapeutic costs may be one half limited with inappropriate depths of implants. Alveoplasty is often a
that of the implant supported fixed prosthesis costs, yet significantly procedure that is needed in conjunction with implant placements in
exceeding the cost of a conventional denture. While the implant over- overdentures to provide sufficient restorative dimension conducive to
denture can provide greatly enhanced stability and retention and has strength. Inadequate alveoplasty as in this case resulted in limitations
13
been shown to markedly enhance quality of life measures, it carries in materials thicknesses leading to the repetitive prosthetic complica-
with it a stigma of a removable oral appliance (a denture). Further, the tions. The maxillary overdenture incorporated four Locator attach-
aforementioned prosthetic complications add to overall treatment/main- ments (Zest Dental Solution, Carlsbad, CA). The mandibular
tenance costs. Thus, enhancing the esthetic quality of the implant framework was similarly undersized. The mandibular overdenture
supported overdenture and improving the durability/robustness of the incorporated four gold copings for Conus abutments (Atlantis
overdenture should be goals when performing overdenture therapy. Dentsply Sirona, Boston, MA).
Digital technology enables the dental laboratory to enhance the
design and manufacture of metal/acrylic overdenture prostheses. The
use of enhanced materials, for example, milling of acrylic teeth as 1.2 | Treatment plan
strong single units versus setting of individual denture teeth and the
use of selective laser sintering of cobalt chrome versus casting, offer The patient was informed of the limitations of the existing prostheses.
potential advantages to implant overdenture construction. Moreover, To address both the esthetic and physical limitations of the existing
the ability to view the prosthesis in three-dimensions during design prostheses, new maxillary and mandibular implant supported over-
and to assess dimensions in cross-section, aid in design of a more dentures were selected. In addition, Locator abutments were selected
robust and durable prosthesis. However, there are limitations to digi- to replace the mandibular conus abutments, thus enabling for greater
tal technology and overdenture construction related to the joining of latitude in mandibular framework design and providing for more
metallic (or resin) frameworks and acrylic teeth and flanges. restorative dimension.
There are at least three ways to construct digitally manufactured
overdentures. One is to design the framework with metal intaglio sur-
faces with milled/printed resin flanges and milled resin teeth. A sec- 1.3 | Treatment and laboratory phases
ond is to produce the metal framework with integrated tissue stops,
use of milled/printed resin flanges and milled resin teeth, and compos- Impressions were made of the maxillary and mandibular edentulous
ite resin intaglio surfaces. A third way is to produce the metal frame- arches using the existing overdentures. Broken prostheses were
work with integrated tissue stops, use milled resin teeth that connect reassembled using cold cure resin (Jet Denture Repair Acrylic, Wheel-
directly to the framework, and to process acrylic resin around the ing, IL) and the missing palatal surface was configured with baseplate
framework and to the milled teeth, thereby creating the intaglio sur- wax (Kerr Dental Corp, Orange, CA). Light body and heavy body
face in heat-processed acrylic resin. vinylpolysiloxane material (Extrude, Kerr Dental Corp, Orange, CA)
120 DUHN ET AL.

F I G U R E 1 (A) Facial photograph of patient's initial presentation. (B) Panoramic radiograph at patient's initial presentation. Note retention
provided by Locator abutments in the maxilla and Conus abutments in the mandible. Importantly, the 4.2 mm diameter mandibular implant in
tooth position #30 was failing. In preparation for replacement of the prostheses, a 4.8 mm diameter was place in that position and successfully
integrated within 8 weeks

F I G U R E 2 (A) Presentation of original maxillary implant overdenture demonstrating communiuted fracture of denture flanges and teeth.
(B) Presentation of original maxillary and mandibular overdentures. Note the moderate posterior tooth wear and resultant vertical overject with
mandibular teeth contacting palatal acrylic resin

were used to capture the intaglio surfaces and peripheral borders, Dental Designer and subsequently produced by selective laser
respectively (Figure 3). The maxillomandibular record was made in cen- sintering (Figure 6).
tric relation (CR) at the existing VDO using the impressed maxillary and The dentition was next designed to be carefully superimposed
mandibular dentures, thus facilitating a single visit for impressions and onto the overdenture framework supports (Figure 7). Based on the
records (Figure 4). The impressed overdentures and the interocclusal denture design and tooth mold selection the design was affirmed by
record were scanned to build a 3D model and print maxillary and man- the clinician and the maxillary and mandibular dentitions were printed
dibular working casts. The impressions were removed, and the existing for try-in with the frameworks (Figure 8). The details of the over-
overdentures cleaned and returned to the patient. Intraoral and denture design are presented in Figure 9.
extraoral photographs were made and the patient dismissed. Subse- The clinical try-in of the frameworks and dentition was performed
quently, the laboratory returned printed maxillary and mandibular work- by attachment of Locator housings to the frameworks using light
ing casts that were mounted on a semi adjustable articulator using bis- cured acrylic resin (Chairside Attachment Processing Material, Zest
acryl duplicates of the original overdentures (Figure 5). Locator Solutions). The Locator housings were “tacked” into place
The mounted casts and photographs were transferred to the den- while the patient was closed in CR upon the printed try-in dentition.
tal laboratory framework design (3Shape Dental System Software, Subsequently, CR was affirmed, the midline was evaluated, and the
Copenhagen Denmark). Dentures were designed to affirm occlusal plane of occlusion required adjustment (Figure 10). An indelible black
plane, incisal edge position, and adjust the midline location to guide marker was used to indicate the desired position of the maxillary
overdenture framework design. The VDO was increased 3 mm to pro- occlusal plane (Figure 10(B)). Photographs were made and transferred
vide longer mandibular tooth dimension and display. Both the maxil- to the laboratory where an additional try-in dentition was printed and
lary and mandibular framework designs were informed by the returned for another esthetic try-in. Because of the interdigitation of
following: (1) robust major connectors (horseshoe maxillary, lingual the dentition with the frameworks, the second try in was simply a
bar mandible), (2) defined and robust support for milled dentition, matter of exchanging the original dentition for the revised dentition
(3) extended facial design to support flanges, (4) relief/clearance for and the try-in was achieved.
the Locator abutments, and (5) 1 mm intaglio surface spacing to Following affirmation of esthetics, phonetics and CR affirmed, the
enable processing of acrylic. Frameworks were designed using 3shape final dentition was milled, attached to the frameworks, and processed
DUHN ET AL. 121

F I G U R E 3 (A) The maxillary overdenture was reassembled with cold acrylic and the palate blocked with base plate wax. (B) After border
molding with heavy body vinyl polysiloxane impression material, the final impression was washed using light body vinyl polysiloxane impression
material. Note the visible location of the Locator abutments that will be attached to the new implant overdenture following prosthesis framework
fabrication. (C) The condition of the mandibular overdenture with gold copings for Conus abutments within the resin. Note the framework does
not support the buccal flanges or posterior aspects of the denture. (D) After border molding with heavy body vinyl polysiloxane impression
material, the final impression was washed using light body vinyl polysiloxane impression material. The designated location of the Conus
abutments will be conserved, but Locator abutments will replace the Conus abutments

F I G U R E 4 Maxillary and mandibular overdenture impressions

with vinyl polysiloxane maxillomandibular record at centric relation. F I G U R E 5 Duplicated dentures were fabricated and used to
The vertical dimension will be increased by 3 mm to account for mount printed maxillary and mandibular models on a semi adjustable
existing wear and to improve lower facial dimension. The dentures articulator to enable seamless transitions from the computer to the
and the interarch relationship were scanned using a desktop scanner clinical environment
to build the 3D model using the existing occlusal plane, incisal edges
and midline as references to design new overdentures
bilaterally symmetric occlusal stops in CR and balanced occlusion in
excursive movements. The digitally designed and manufactured
to the stone casts using conventional denture processing techniques implant overdentures were stable, retentive and provided improved
(Lucitone 199, Dentsply, York, PA). Photographs of the final prosthese esthetics by enhanced quality of the milled dentition, increased verti-
are presented in Figure 11. The delivery visit for the processed pros- cal dimension to permit mandibular tooth display and increased lower
theses involved the assessment of fit, adjustment of processed flanges third facial dimension (Figure 12).
where indicated by pressure indicating paste, replacement of The resulting prosthesis was accepted by the patient. The digital
processing caps with Locator resilient attachments, and evaluation of design was recapitulated in the final denture and met the stated
occlusion using articulating papers and shim stock to achieve multiple esthetic and functional goals of treatment and the expectations of the
122 DUHN ET AL.

F I G U R E 6 (A) Pre-requisite design of dentures to guide overdenture framework design. (B) Facial view of mandibular framework design
showing retention of facial surface of the alveolus and posts to support the milled dentition. Note parallelism of posts requires correction.
(C) Occlusal view of maxillary framework design with superimposed maxillary overdenture design

F I G U R E 7 (A) Occlusal view of the SLM printed and polished maxillary framework illustrates the polished major connector, relief for locator
abutments and perforation retention for the overdenture acrylic. (B) Lateral view of the maxillary framework demonstrating the parallel posts that
support and interdigitate the monolithic, milled dentition. Note the framework with retentive elements extends to the facial aspects of the
alveolus to support the overdenture flanges. (C) Occlusal view of the SLM printed and polished mandibular framework illustrates the polished
major connector, relief for locator abutments and perforation retention for the overdenture acrylic. (D) Lateral view of the mandibular framework
demonstrating the parallel posts that support and interdigitate the monolithic, milled dentition. Note the framework with retentive elements
extends to the facial aspects of the alveolus to support the overdenture flanges. SLM, selective laser melting

patient (Figure 13). Oral hygiene instruction emphasizing the potential denture hygiene and simplifies repair, if required. Implant retained
risks of peri-implantitis and denture stomatitis were given. Denture overdentures can accommodate for marked alveolar resorption to
hygiene instruction was also provided and information concerning the restore facial contours. In addition, they offer financial advantages
ensuing requirement for replacement of resilient attachments was when compared to implant supported fixed dentures and prostheses.
given. There are relative disadvantages when comparing implant over-
dentures to fixed implant solutions. Implant retained overdentures
may incur modestly more implant loss than fixed implant solutions for
2 | DISCUSSION edentulism. Kern et al. established by systematic review and meta-
analysis that the implant loss rates for fixed versus removable restora-
The implant retained overdenture is one of several implant-based tions on implants were (0.23 [95% CI 0.18; 0.29] vs. 0.35 [95% CI
approaches to rehabilitation of the edentulous patient. The relative 0.28; 0.44]; p = 0.0148).3 In a study of Japanese adults (average age
advantages include its removable character that enables oral and 62), risk factors associated with loss of implants supporting removable
DUHN ET AL. 123

F I G U R E 8 (A) Occlusal view

of milled monolithic maxillary
dentition attached to the
supporting framework posts.
(B) Facial view of the milled
monolithic maxillary dentition
attached to the supporting
framework posts. (C) Occlusal
view of milled monolithic
mandibular dentition attached to
the supporting framework posts.
(D) Facial view of the milled
monolithic mandibular dentition
in their relation to the supporting
framework posts

reported 97% implant survival for unsplinted implants supporting

maxillary overdentures.9 The use of bars to support implant over-
dentures has not proven to improve patient satisfaction and prosthe-
sis retention.15
The implant overdenture prosthesis is also associated with rela-
tively greater requirement for maintenance and repair.16 While both
fixed and removable implant solutions to edentulism offer high suc-
cess and satisfaction, and both types of prostheses require prosthesis
maintenance and management of prosthetic complications, implant
overdentures require greater intervention. Goodacre et al.13 have
most recently revealed that maintenance/complications occurred with
overdentures versus fixed complete dentures. In this review, the stud-
F I G U R E 9 Overdenture construction design. 1. Selective Laser ied population had 17 reported categories of complications. Among
Melted (SLM) cobalt chrome framework; note relief at tissue surface, these complications, several reflected the physical integrity of the
support for buccal flange and supporting/orienting post for overdenture. Reported were 14% overdenture repair, 12% over-
CAD/CAM milled dentition. 2. Polymethylmethacrylate resin denture remake, 12% denture tooth fracture, 10% extension bar frac-
processed to assemble milled teeth and SLM framework. 3. Milled
ture, and 9% overdenture fracture. Based on the existing evidence
monolithic dentition; note the intimate relationship to the framework
that permits exchange of various dentitions to facilitate try-in and regarding implant overdenture prosthesis, there is need for improve-
adjustment of design. 4. Locator “denture cap”; note relief designed ment of the physical integrity and longevity of overdenture prosthe-
into SLM framework. The denture cap is picked up in the framework ses. The present digital workflow was adopted to enhance the
clinically using acrylic resin. SLM, selective laser melting physical integrity of implant overdentures.
The framework and tooth components of the prosthesis were
designed and fabricated within the digital environment. While others
prostheses included implants placed in the maxillary arch and male have reported on the digital fabrication of overdenture frameworks or
sex.10 In fact, low-implant survival rates in the maxilla have been implant bars, the present work illustrates the possibility of simulta-
repeatedly associated with fewer than four implants, machined sur- neous, integrated design and fabrication of the framework and denti-
faces, and short (<10 mm) implant length and removable over- tion for the overdenture. Further, the rapid printing of the dentition
dentures.14 In the present case, four implants placed with substantial provides a relatively inexpensive approach to evaluation of phonetics,
anterioposterior spread (>10 mm) were stable and presented with esthetics, and occlusion. In the present case, minor esthetic changes
minimal marginal bone loss at the time of retreatment of approxi- in the design and fabrication of the dentition were made by the dental
mately 3 years following implant placement. This success of technician who was directed by digital photography. Thus, no casts or
unsplinted implants is aligned with the findings of Anadioti et al. who prostheses were exchanged to provide the dentist with the alternative
124 DUHN ET AL.

F I G U R E 1 0 Tooth try-in and adjustment. (A) Facial photograph taken in centric relations reveals good occlusal relationships, however, the
occlusal plan is lower on the patient's left side. The monolithic printed dentitions were reversibly attached to the frameworks using bite
registration material. (B) On the articulator, the desired adjustment was indicated using a black indelible marker and photographed. This
photograph directed redesign of the monolithic maxillary dentition to adjust the occlusal plane and esthetic tooth display without sending
materials back to the laboratory

F I G U R E 1 1 (A) Conventional processing of denture resin was performed to connect the milled maxillary monolithic dentition to the maxillary
SLM framework. (B) Intaglio surface of the processed maxillary overdenture demonstrates the acrylic incorporation of the retentive base and the
attached Locator denture caps with processing retentive elements in place. The major connector serves as the tissue stops for this framework.
(C) Conventional processing of denture resin was performed to connect the milled monolithic mandibular dentition to the mandibular SLM
framework. (D) Intaglio surface of the processed mandibular overdenture demonstrates the acrylic incorporation of the retentive base and the
attached Locator denture caps with processing retentive elements in place. Note the framework extends beyond the alveolar height of contour to
the facial surface and noe the three tissue stops designed in this framework. SLM, selective laser melting

tooth arrangement for the next try-in. These factors illustrate the except for the palatal major connector, which was intimate with
advantages of digital workflow in the fabrication of an implant supporting mucosa. This opposes designs where the intaglio surface is
retained overdenture. This same workflow applies to implant metal (not enabling reline procedures; Figure 11). The framework
supported overdentures where a bar and superstructure would also design further specified relieved areas to permit intraoral pick of the
be designed between the implant abutments and the dentition. Locator housing, thus assuring passive insertion and removal to enable
Essential to their design was the a priori design of a denture to resilient attachment longevity.17 The framework design also included
guide tooth position and derived framework design. The framework the addition of posts to support and index the full arch dentitions; this
design was specified to provide for acrylic resin intaglio surfaces, allowed for simple assembly of the framework and teeth for the
DUHN ET AL. 125

F I G U R E 1 2 Denture delivery. (A) Intraoral facial view of oral condition immediately prior to the insertion of the new digitally designed and
manufactured overdentures. (B) Intraoral facial view of the inserted maxillary and mandibular implant overdentures. Note the adjustment of the
occlusal plane has been achieved as prescribed

F I G U R E 1 3 (A) Facial photograph revealing midline discrepance, tooth wear and obvious repair to original maxillary implant overdenture.
(B) Facial photograph of digitally designed and manufactured implant retained overdentures. The midline discrepancy has been resolved and
mandibular tooth display was achieved by increasing vertical dimension of occlusion by 3 mm without altering location of the maxillary incisal
edge position or occlusal plane

exchange of alternative dentitions to address changes indicated at the complete arch from cross-linked resin23 offers potential enhancement
clinical evaluation visit(s). of strength and may prevent the debonding and fracture of teeth that is
Multiple software programs offer technicians the ability to design among the most frequently reported problems for implant prostheses.13
18
partial denture and overdenture frameworks. A 3D model of the Another report used intraoral scanning to produce tooth-supported
teeth, alveolar ridges, and mucosa can be derived from intraoral scan- overdentures by milling of tooth colored resin to treat oligodontia.24
ning (direct) or by desktop scanning of accurate intraoral impressions Most recently, Yang and coworkers used a digital approach to denture
(indirect) as illustrated here. It is noted that the direct approach pro- duplication to digitally manufacture an overdenture following implant
vides the more accurate approach, however, the scanning of placement.25 In this case, the duplicate denture was printed to serve as
completely edentulous arches is technically and practically challeng- an impression tray and for making of CR records and transfer of mor-
19
ing and the overdenture frameworks utilize no rests or clasps that phologic data. An integrated metal framework was designed and pro-
require highest fidelity. The digital framework design is exported to a duced by direct metal printing. Another approach involved integrating
selective laser melting (or selective laser sintering) machine for fabri- the CBCT scan for generation of a fixture level overdenture bar using
cation of the framework. Others have shown that digitally produced digital design and milling technology. The authors indicated that 12 of
frameworks made from stone or printed models fit less well than con- 15 bars achieved passive adaptation and fit.26 Clearly, various workflows
ventionally cast frameworks, particularly in the major connector/tis- are being considered to improve the accuracy of components, enhance
sue interface regions.20 The accuracy of SLM (selective laser melting) the strength and utility of overdenture components and simplify the
framework fit, however, has been deemed clinically acceptable.21 clinical efforts in providing exemplary implant prostheses by the use of
Others have also reported the use of digital technology to produce digital technology.
implant overdenture prostheses. Lin et al.22 utilized intraoral scanning,
milling and SLM to produce a bar retained overdenture, but conven-
tional processing of resin teeth and acrylic resin flanges was used to 3 | CONC LU SION
complete the prosthesis. Here we have utilized the digital design capac-
ity of current software to model the prosthesis as a denture to inform This presentation demonstrates the various challenges in managing
framework design and dentition design. The milling of the dentition as a implant retained overdenture prostheses. In an effort to solve the
126 DUHN ET AL.

recurrent fracture of the acrylic flanges and teeth, retreatment using 13. Goodacre C, Goodacre B. Fixed vs removable complete arch implant
alternatively designed frameworks and milled monolithic dentitions prostheses: a literature review of prosthodontic outcomes. Eur J Oral
Implantol. 2017;10(suppl 1):13-34.
was achieved using digital technology. The framework and teeth were
14. Sadowsky SJ, Zitzmann NU. Protocols for the maxillary implant over-
integrally designed and produced by selective laser melting and mill- denture: a systematic review. Int J Oral Maxillofac Implants. 2016;31
ing. During the construction of this prosthesis, printed resin dentitions suppl:s182-s191.
were used to validate esthetics, phonetics, and esthetics. The two 15. Takashima M, Arai Y, Kawamura A, Uoshima K. Risk factors associ-
ated with post-loading implant loss of removable and fixed implant-
components were assembled by conventional processing of poly-
supported prostheses in edentulous jaws. J Prosthodont Res. 2018;62
methylmethacrylate. Pickup of resilient overdenture attachments was (3):365-369.
achieved clinically to complete the prostheses. Digital technology 16. Goodacre CJ, Bernal G, Rungcharassaeng K, Kan JY. Clinical complica-
enabled control of framework dimensions and related strength and tions with implants and implant prostheses. J Prosthet Dent. 2003;90
(2):121-132.
the use of robust materials to address prosthesis longevity.
17. Nissan J, Oz-Ari B, Gross O, Ghelfan O, Chaushu G. Long-term pros-
thetic aftercare of direct vs. indirect attachment incorporation tech-
ORCID niques to mandibular implant-supported overdenture. Clin Oral
Lyndon F. Cooper https://orcid.org/0000-0002-6577-781X Implants Res. 2011;22(6):627-630.
18. Ye H, Ning J, Li m, et al. Preliminary clinical application of removable
partial denture frameworks fabricated using computer-aided design
RE FE R ENC E S
and rapid prototyping techniques. Int J Prosthodont. 2017;30:
1. Thalji G, McGraw K, Cooper LF. Maxillary complete denture out- 348-353.
comes: a systematic review of patient-based outcomes. Int J Oral 19. Gan N, Xiong Y, Jiao T. Accuracy of intraoral digital impressions for
Maxillofac Implants. 2016;31(suppl s169):81. whole upper jawsl including full dentitions and palatal soft tissues.
2. Carlsson GE. Clinical morbidity and sequelae of treatment with com- PLos One. 2016;11:e0158800.
plete dentures. J Prosthet Dent. 1998;79(1):17-23. 20. Soltanzadeh P, Suprono MS, Kattadiyil MT, Goodacre C,
3. Felton DA. Edentulism and comorbid factors. J Prosthodont. 2009;18 Gregorius W. An in vitro investigation of accuracy and fit of conven-
(2):88-96. tional and CAD/CAM removable partial denture frameworks.
4. Feine JS, Carlsson GE, Awad MA, et al. The McGill consensus state- J Prosthodont. 2019;28(5):547-555.
ment on overdentures. Mandibular two-implant overdentures as first 21. Chen H, Li H, Zhao Y, Zhang X, Wang Y, Lyu P. Adaptation of remov-
choice standard of care for edentulous patients. Montreal, Quebec, able partial denture frameworks fabricated by selective laser melting.
may 24-25, 2002. Int J Oral Maxillofac Implants. 2002;17(4):601-602. J Prosthet Dent. 2019;122(3):316-324.
5. Vahidi F, Pinto-Sinai G. Complications associated with implant- 22. Lin WS, Chou JC, Metz MJ, Harris BT, Morton D. Use of intraoral dig-
retained removable prostheses. Dent Clin N Am. 2015;59(1):215-226. ital scanning for a CAD/CAM-fabricated milled bar and superstruc-
6. Ahmad R, Abu-Hassan MI, Chen J, Li Q, Swain MV. The relationship ture framework for an implant-supported, removable complete dental
of mandibular morphology with residual ridge resorptionassociated prosthesis. J Prosthet Dent. 2015;113(6):509-515.
with implant-retained overdentures. Int J Prosthodont. 2016;29(6): 23. Han W, Li Y, Zhang Y, et al. Design and fabrication of complete den-
573-580. tures using CAD/CAM technology. Medicine (Baltimore). 2017;96(3):
7. Slot W, Raghoebar GM, Cune MS, Vissink A, Meijer HJA. Four or six e6030.
implants in the maxillary posterior region to support an overdenture: 24. Cooper LF, Culp L, Luedin N. A digital approach to improved over-
5-year results from a randomized controlled trial. Clin Oral Implants dentures for the adolescent oligodontia patient. J Esthet Restor Dent.
Res. 2019;30(2):169-177. 2016;28(3):144-156.
8. Slot W, Raghoebar GM, Cune MS, Vissink A, Meijer HJ. Maxillary 25. Yang Y, Yang Z, Lin WS, Chen L, Tan JG. Digital duplication and 3d
overdentures supported by four or six implants in the anterior region: printing for implant overdenture fabrication. J Prosthodontics. 2020.
5-year results from a randomized controlled trial. J Clin Periodontol. https://doi.org/10.1111/jopr.13225.
2016;43(12):1180-1187. 26. Mangano F, Mangano C, Margiani B, Admakin O. Combining intraoral
9. Anadioti E, Gates WD 3rd, Elpers J, De Kok IJ, Cooper LF. Retrospec- and face scans for the design and fabrication of computer-assisted
tive cohort analysis of maxillary overdentures retained by unsplinted design/computer-assisted manufacturing (CAD/CAM) polyether-
implants. J Prosthet Dent. 2019;122(3):301-308. ether-ketone (PEEK) implant-supported bars for maxillary over-
10. Kern JS, Kern T, Wolfart S, Heussen N. A systematic review and dentures. Scanning. 2019;2019:4274715.
meta-analysis of removable and fixed implant-supported prostheses
in edentulous jaws: post-loading implant loss. Clin Oral Implants Res.
2016;27(2):174-195.
11. Heydecke G, Zwahlen M, Nicol A, et al. What is the optimal number
of implants for fixed reconstructions: a systematic review. Clin Oral How to cite this article: Duhn C, Thalji G, Al-Tarwaneh S,
Implants Res. 2012;23(suppl 6):217-228. Cooper LF. A digital approach to robust and esthetic implant
12. Papaspyridakos P, Chen CJ, Chuang SK, Weber HP, Gallucci GO. A
overdenture construction. J Esthet Restor Dent. 2021;33:
systematic review of biologic and technical complications with fixed
implant rehabilitations for edentulous patients. Int J Oral Maxillofac 118–126. https://doi.org/10.1111/jerd.12711
Implants. 2012;27(1):102-110.