Dental News is a professional magazine with articles from high ranked universities and influential dentists all over the world. Our Articles are from universities like New York University, Tufts University, Baylor University, Temple University just to cite a few.
CAD/CAM technology for fabricating complete dentures
Dr. Maha Ghotmi Dr. Danielle El Hakim Dr. Najib Abou Hamra Dr. Rita Eid
The process for fabricating complete dentures has
three major steps: the impression procedures, the denture design and the
This paper is about the fabrication of a removable
complete denture using CAD/CAM technology. It has the potential to simplify the
traditional process and resolve the associated problems. CAD/CAM technique is a
two-step appointment process. Impressions, jaw relation records, occlusal plane
orientation, tooth mold, shade selection and maxillary anterior tooth
positioning record are registered in the first appointment. The second
appointment is for insertion.
Aided Design – Computer Aided Manufacturing (CAD/CAM) technology has already
been used significantly in dentistry. CAD software defines the geometry of an
object while the CAM software directs the fabrication process1,2.
the early 1980s, CAD/CAM was used to produce clinical dental restorations when
Andersson envisioned the use of titanium for fabrication of crowns1.
Another important dental application of CAD/CAM technology also occurred in the
1980s. Mörmann developed an interest in tooth-colored restorations. In
September of that same year, he placed the first chairside fabricated ceramic
restoration with equipment introduced and marked as the CEREC 1 system3.
In the recent 20 years, dozens of dental CAD/CAM systems have been presented
for inlay, crown, veneer and fixed partial denture4-6.
the development on CAD/CAM for removable complete denture has been very slow4.
Advanced Manufacturing Technology (AMT) has not been successfully applied in
this field. Goodacre et al wrote, “When the CAD/CAM technology for fabricating
complete dentures becomes commercially available, it will be possible to scan
the denture base morphology and tooth positions recorded with this technique
and import those data into a virtual tooth arrangement program where teeth can
be articulated and then export the data to a milling device for the fabrication
of the complete dentures”. Over years, different methods for duplicating7
and fabricating complete dentures using CAD/CAM system have been tried. With
the introduction of commercially available CAD/CAM denture systems like AvaDent
and Dentca, Inc., the era of digital complete dentures has arrived2,4,8.
purpose of this article is to describe the clinical procedure required to
fabricate a complete denture using CAD/CAM technology.
Conventional fabrication technique of a removable complete denture
Removable complete denture
is a dental prosthesis, which replaces the entire dentition and associated
structures of the maxilla and mandible9. A complete denture
functions to restore aesthetics, mastication and speech. It has various parts
and surfaces such as denture base, flange of denture, denture teeth and denture
The conventional complete
denture technique is a five-step appointment process2,10
-Making final impressions
-Creating jaw relationship
-Arranging prosthetic teeth
-Placement/insertion of complete
Dentca and AvaDent starting kits (Courtesy of Dr Tony Daher)
CAD/CAM fabrication technique of a removable complete denture
advanced fabrication technique is a two-step appointment process2
-Impressions, jaw relation records,
occlusal plane orientation, tooth mold and shade selection, and maxillary anterior tooth
-Insertion of dentures
The process for fabricating
complete dentures has three major steps: the impression procedures, the denture
design and the denture fabrication11.
The impression procedure
The procedure involves the
fabrication of a putty cast formed by pressing mixed polyvinyl siloxane putty
into the intaglio surface of the patient’s existing dentures. If these dentures
are unacceptable then diagnostic casts can be generated from a preliminary
impression. And if the denture is not adapted to the mucosa, a refitting or
relining can be made2,10.
It is important to check the adaptation
of the thermoplastic trays on the cast andtry them in the patient’s mouth to make the necessary adjustments. It is
also important that the maxillary tray extends posteriorly to cover the area of
the vibrating line and the pterygomaxillary fissures while the mandibular tray
covers the retromolar pads2.
After applying an appropriate adhesive
and adding tissue stops, a border molding impression material or a medium body
polyvinyl siloxane impression material is then used to border mold the
maxillary and mandibular trays employing the method used with conventional
custom trays. Final impressions of the maxillary and mandibular arches are made
using either with a specific impression material or with a light-body polyvinyl
siloxane impression material2. (Goodacre et Al use speech method to
identify muscular and phonetic locations for the prosthetic teeth and to
establish palatal morphology;
this requires impressions that record the shape of both the intaglio and cameo
surfaces of complete denture bases.)1
Figure 2: Maxillary and
mandibular final impressions (Courtesy of Dr Tony Daher)
The AvaDent denture technique uses an Anatomical
Measuring Device (AMD) that can be adjusted to the desired occlusal
vertical dimension. This AMD maintains thisdimension while centric relation is recorded
using the incorporated gothic arch tracing plate and stylus. The AMD is also
used to determine the correct amount of upper lip support, the position of the
maxillary six anterior teeth, and the desired mediolateral orientation of the
occlusal plane. The AvaDent orientation ruler is attached to the maxillary AMD
for determining the appropriate occlusal plane. The angle is noted and recorded
on the laboratory work authorization form. The midline on the lip support
flange as well as the smile line are marked. The size of the maxillary anterior
teeth is selected from the three available tooth size templates that matches
the patient’s desired tooth size. To serve as a guide during denture
fabrication, flowable composite resin is applied to the inside of the selected
tooth mold template, then positioned carefully in place and light polymerized
to affix the template in position. AvaDent registration material is injected
into the space between the maxillary and mandibular arches, with the jaw
stabilized in centric relation. (Dentca uses another specific device for these
Figure 3: Interocclusal
records (Courtesy of Dr Tony Daher)
The denture design
After disinfection, the final
impressions and all the registrations are mailed to the company producer of the
digital dentures, along with any special instructions. At this stage, the
impressions and interocclusal records are scanned, virtual casts are created
and articulated, teeth are arranged and bases are virtually formed1,2.
Figure 4: Virtual casts and
teeth arrangement (Courtesy of Dr Tony Daher)
The denture fabrication
The denture base is milled
from a block of pink denture base resin
with recesses that accurately fit each denture tooth, and the teeth are bonded
with a proprietary bonding mechanism. The denture base can be fabricated from
different choices of base material, and different options are available for the
Figure 5: Milling and
gluing stages (Courtesy of Dr Tony Daher)
Another technique for the
denture fabrication exists: the 3-D laser lithography. This rapid prototyping
(RP) technology was originally developed to fabricate prototypes for industrial
purposes. This method automatically constructs physical models from
computerized three-dimensional (3D) data. The RP systems join liquid, powder,
or sheet materials to form physical objects. Through Layer by layer technique,
RP machines process plastic, paper, ceramic, metal, and composites from thin,
horizontal cross sections of a computer model. RP has recently seen successful
application in various medical fields, such as in the fabrication of implant
surgical guides12,13, maxillofacial prosthetics14-16 and
frameworks for removable partial dentures17,18.
After finishing the
dentures, it’s time for the second appointment where the insertion of the
complete dentures is made. The placement and post-placement adjustments of
CAD/CAM complete dentures are similar to the placement of conventional
dentures. The patient is seen as needed for routine follow-up and maintenance
Advantages and disadvantages of CAD/CAM technology
Several advantages to the patient and the dental
practitionar are offered2
-The clinical chair time is
reduced considerably; all clinical data needed are recorded in the same
- The digital data for each
case is saved; a spare denture or a radiographic or surgical template can be
-Because the digital data
are associated with a specific practitioner, patients will return to the same
dentist when future treatment is needed.
-Because the denture base is
fabricated by machining, polymerization shrinkage of the resin is eliminated,
and the fit of the denture base is superior to that of conventionally denture
-Due to the method of
processing the acrylic resin for denture bases at fifty times the conventional
processing pressure, there is less porosity, and denture base material may have
less C. Albicans adherence.
Fewer disadvantages are present
-The artificial teeth and denture base are
equipped with different colors and properties. The artificial teeth need high
abrasion resistance and an aesthetic appearance. It is difficult to cut the
artificial teeth from a single property block. Thus, only the denture base
is fabricated by cutting then commercially available artificial teeth are
adhered to the denture base. Special adhesives with
higher adhesive properties are being developed10.
-Another disadvantage is the
missed trial insertion appointment. This step allows making judgments of
esthetics and pronunciation and verification of jaw relationship records,
including orientation of the occlusal plane, vertical dimension, tongue space,
tooth positioning, palatal seal and soft tissue support for proper external
form. This is why a third appointment in the advanced fabrication technique
could be added19. AvaDent Advanced Try-In (ATI) uses the final base
with teeth waxed on. This technique provides teeth adjustment, relining, VDO
modification, full adjustment capabilities. The only problem is the additive
cost. Dentca Try-In is a Stereo Lithographic Analog (SLA) of the digitally
designed denture that fits like the final denture with a close final contours
and the possibility of checking the midline, the insical plane and the lip
support. The problem is the frosty clear appearance of teeth that cause
difficulties to evaluate shade and esthetics, plus the fact that we cannot move
It is now possible to fabricate a complete denture with
This fabrication has positive benefits
for both the patient and the practitioner.
However the final result depends on the
skill and knowledge of materials, anatomy, occlusion, function, making
excellent impressions, registering the interocclusal record with a special device
and determining the proper esthetic parameters.
1. Goodacre CJ, Garbacea A,
Naylor WP, Daher T, Marchack CB, Lowry J. CAD/CAM fabricated complete dentures:
concepts and clinical methods of obtaining required morphological data. J
Prosthet Dent 2012; 107: 34-46.
2.Kattadiyil MT, Goodacre CJ.
CAD/CAM technology: application to complete dentures. J Loma Linda University
Dent 2012; 23: 16-23.
3.Mörmann WH. The evolution
of the CEREC system. J Am Dent Assoc 2006; 137suppl: 7S-13S.
4. Sun Y, Lü P, Wang Y. Study
on CAD&RP for removable complete denture. Comput Methods Programs Biomed
2009; 93: 266-272.
5. Harder S, Kern M. Survival
and complications of computer aided-designing and computer-aided manufacturing
vs. conventionally fabricated implant-supported reconstructions: a systematic
review. Clin Oral Implants Res 2009; 20 Suppl 4: 48-54.
6. Kelly JR. Developing
meaningful systematic review of CAD/CAM reconstructions and fiber-reinforced
composites. Clin Oral Implants Res 2007; 18 Suppl 3: 205-217.
7. Kawahata N, Ono H, Nishi Y,
Hamano T, Nagaoka E. Trial of duplication procedure for complete dentures by
CAD/CAM. J Oral Rehabil 1997; 24: 540-548.
8. Kattadiyil MT, Goodacre CJ,
Baba NZ. CAD/CAM complete dentures: a review of two commercial fabrication
systems. J Calif Dent Assoc 2013; 41:
9. Wittneben JG, Wright RF,
Weber HP, Gallucci GO. A systematic review of the clinical performance of
CAD/CAM single-tooth restorations. Int J Prosthodont 2009; 22: 466-471.
10.Kanazawa M, Inokoshi M,
Minakuchi S, Ohbayashi N. Trial of a CAD/CAM system for fabricating complete
dentures. Dent Mater J 2011; 30: 93-96.
11. Maeda Y, Minoura M,
Tsutsumi S, Okada M, Nokubi T. A CAD/CAM system for removable denture. Part I:
fabrication of complete dentures. Int J Prosthodont 1994; 7:17-21.
12. Sarment DP, Sukovic P,
Clinthorne N. Accuracy of implant placement with a stereolithographic surgical
guide. Int J Oral Maxillofac Implants 2003; 18: 571-577.
13. Di Giacomo GA, Cury PR, de
Araujo NS, Sendyk WR, Sendyk CL. Clinical application of stereolithographic
surgical guides for implant placement: preliminary results. J Periodontol 2005;
Mardini M, Ercoli C, Graser GN. A technique to produce a
mirror-image wax pattern of an ear using rapid prototyping technology. J
Prosthet Dent 2005; 94: 195-198.
15. Sykes LM, Parrott AM, Owen
CP, Snaddon DR. Applications of rapid prototyping technology in maxillofacial
prosthetics. Int J Prosthodont 2004; 17: 454-459.
16.Subburaj K, Nair C, Rajesh
S, Meshram SM, Ravi B. Rapid development of auricular prosthesis using CAD and
rapid prototyping technologies. Int J Oral Maxillofac Surg 2007; 36: 938-943.
17.Williams RJ, Bibb R, Rafik
T. A techniquefor fabricating patterns
for removable partial denture frameworks using digitized casts and electronic
surveying. J Prosthet Dent 2004; 91: 85-88.
18.Williams RJ, Bibb R,
Eggbeer D, Collis J. Use of CAD/CAM technology to fabricate a removable partial
denture framework. J Prosthet Dent 2006; 96: 96-99.
19.Inokoshi M, Kanazawa M,
Minakuchi S. Evaluation of a complete denture trial method applying rapid
prototyping. Dent Mater J 2012; 31: 40-46.
By Dr. Sawsan Nasreddine,Dr. Fida Sayah, Dr. Fady Kassir, and Pr. Mounir Doumit, of the Lebanese University, School of Dentistry
Discoloration of the tooth can erode the sparkle from a smile. There are many factors that contribute to tooth staining. It is important to understand that in some cases staining can be prevented but in others it cannot. There are two types of tooth discoloration: extrinsic which affects teeth from the outside and intrinsic which affects the teeth from the inside. The purpose of this article is to review literature on the etiologies and classification of tooth staining and discoloration. Key words: Etiology, classification, extrinsic discoloration, intrinsic discoloration
Introduction The appearance of the dentition is of concern to a large number of people seeking dental treatment and the color of the teeth is of particular cosmetic importance. Tooth discoloration is usually esthetically displeasing and p…
problem of inferior alveolar nerve involvement during surgical procedure of the
removal of lower third molars is often a source of litigations1,2,3.
At the same time the impact of this on a person’s quality of life should not be
or partial odontectomy reduces the likelihood of nerve injury by insuring
retention of the vital roots when they are close or associated with the
inferior alveolar nerve as evaluated by plain radiography or CBCT4,5.
method aims to remove only the crown part of an impacted mandibular third molar
while leaving the root and pulp undisturbed, thereby avoiding direct or
indirect damage to the inferior alveolar nerve6,7,8. Literature
so far has hailed its merits and many practitioners regularly use the approach
of coronectomy in order to minimise Inferior alveolar nerve injuries. This
technique got in lime light in last decade although r…