Written by David Little, DDS, and Troy P. Apparicio, CDT Friday, 13 January 2012 16:18
In the past, patients suffering from tooth loss faced many challenges on their road to recovery. Aside from physical limitations like premature aging and loss of chewing efficiency, emotional effects of tooth loss included bereavement, lowered self-confidence, altered self-image, dislike of appearance, and a feeling of taboo when discussing their problem with others.1 Along with these common behaviors, patients also found themselves attempting to keep their problem a secret, and often had difficulty socializing and forming close relationships.1
The loss of hard and soft tissues is associated with a loss of orofacial support.2 Because of this, facial aesthetics, phonetics, and collapse of vertical dimensions coincided with the appearance of premature aging caused by the lack of lip support and a decrease in facial height.2 Changes in orofacial structure led to impaired oral function, pain, insufficient retention due to bone loss in the residual ridge, and instability of conventional dentures, along with nutritional and psychological changes, which caused many issues for patients.2
The conventional treatment for this condition, removable prostheses, exacerbated many of these emotional and physical effects since dentures have been uncomfortable.3,4 Because traditional dentures seldom provide the desired stability, patients found themselves struggling to keep them in place with their tongue, cheek, and lip muscles.3,4
The average bite-force for dentate patients, 150 to 250 psi, and for those who clenched or were bruxers, 1,000 psi, was reduced to 50 psi when the patient became edentulous.3,4 After 15 or more years wearing dentures, many patients' bite-force and chewing efficiencies were reduced even further to 5.6 psi, making simple functional tasks like eating very difficult.3,4
Implant-supported overdentures, the new standard of care for edentulous patients, offer many benefits over fixed options.2 To achieve the best results, clinicians realized that it was necessary to place endosseous osseointegrated implants under removable prostheses to preserve bone and to provide prosthetic retention, stability, and a degree of occlusal support.2 It was also discovered that quality of life, self-confidence, nutritional state, and facial aesthetics improve with implant-supported or implant-retained prostheses.3,4 Patients seeking to correct chronic pain in load-bearing areas will find that implant-retained overdentures, aside from improving aesthetics, offer more comfort and psychological benefits.2 Overall, this type of prostheses allows patients to function normally in society and enables them to eat what they want, instead of only what they can.2
However, despite enhancements in denture fit and comfort, there still has been a need for denture teeth capable of withstanding implant forces and that also resemble natural looking dentition.3,4 Because implant-retained and supported dentures are very stable intraorally, they require materials that are much stronger and, more importantly, demonstrate a higher resistance to wear.5 Aesthetics and better bite characteristics also have become more desirable traits by patients.5
Newly available denture base materials and denture tooth technology provide a more comfortable fit with improved biocompatibility.5 With advancements in CAD/CAM technologies, denture teeth can now be designed for advanced occlusal schemes and demonstrate decreased incidences of breakage because of their density.5 Displaying less change, especially in the fifth dimension, these advanced materials represent the future of implant supported and retained prostheses.5
New Generation of Denture Teeth Introduced
Denture teeth fabricated from inorganic nanofillers that are integrated in a highly cross-linked, tough elastic matrix (Mondial [Heraeus Kulzer]) demonstrate lifelike opalescence, high abrasion resistance, biocompatibility, plaque resistance, and color stability. Also, because they are fabricated using CAD/CAM technology, harmonious tooth set-up and reproducible articulation are ensured.
Based on the Magister/Orthognath molds, which have seen worldwide success during the last 40 years, aesthetics, function, and material quality have been improved significantly with the Mondial line of denture teeth. To improve aesthetics, the labial, buccal, and occlusal surfaces have been modified, along with restructuring of the layering to match the Vitapan Classical shade system (Vident). The layering technique and material improves opalescence, while integrated nanofillers improve optical characteristics like attainable depth and lifelike color.
To improve function, Mondial dentures have a precisely defined centric relationship that permits clear cut setup. Because they are designed using CAD/CAM technology, identical sets of teeth can be created with identical shape for all tooth sizes. With the high functional accuracy created through CAD/CAM utilization, there also are no frictional surfaces that resist function.
Improved material sciences, including nanopearls, allow Mondial dentures to demonstrate high abrasion resistance, without altering hardness or elasticity, which was a common problem with conventional polymethyl methacrylate (PMMA) materials. However, the polish obtained with Mondial prostheses is similar to that attainable with PMMA dentures. The advanced material science also allows these dentures to demonstrate improved bond strength between layers to improve retention rates.
Overall, the quality of the Mondial line of denture teeth provides natural light dynamics and a material that is highly resistant to discoloration for a more natural look. Because of the injection and compression INCOMP manufacturing process, bubble-and porosity-free prostheses also can be expected.
This article describes a case in which a team approach was undertaken to meet the patient's expectations. By first visualizing the case conceptually, then in wax and ultimately in the acrylic dentures, the team overall was able to deliver a highly aesthetic and functional implant-supported prostheses.
Diagnosis and Treatment Planning
A 44-year-old man presented stating, "Doctor, I am in trouble" (Figures 1 and 2). The patient's chief complaints were pain, bad taste, and an overall unwell feeling. He was concerned about having dentures at a young age, since his parents had dentures and could not eat well, and he did not want his teeth to have their false teeth appearance.
|Figure 1. Preoperative view.||Figure 2. Preoperative retracted close-up view of the patient's maxillary and mandibular dentition.|
|Figure 3. Preoperative panoral radiograph of the patient's oral environment.|
A comprehensive examination was performed, including clinical examination, a digital panoramic radiograph (Figure 3), full-mouth radiographs, and clinical photographs. An oral cancer screening was then performed, which resulted in negative findings. Finally, a cone beam computed tomography (CBCT) scan was taken, which is the authors' standard of care for any patient considering implant treatment. Using SimPlant software (Materialise Dental) the case was treatment planned to place 4 implants interforaminally. Following extractions and alveloplasty, 4 implants were placed in the positions planned using the CBCT scan and SimPlant software.
It was explained to the patient that by extracting all teeth, it would be possible to rid the oral tissues of infection. Also, by placing artificial roots (ie, implants) in the mandible, the bone could be kept from resorbing and the lower denture retained securely.
The extracted upper teeth would be immediately replaced with an upper transitional denture. The lower teeth would then be extracted and a radical alveoplasty performed. Four implants (ANKYLOS [DENTSPLY Tulsa Dental Specialties]) were then to be placed with SynCone conical abutments, along with pickup gold caps in the immediate loaded transitional lower denture. It was necessary to place 4 implants, instead of 2, to ease the load on the ridge and decrease the mucosal bearing areas during occlusal function.2,6 After integration of the implants, new dentures developed from Mondial teeth would be fabricated and placed.
The implants were placed and then immediately loaded using overdenture abutments (ANKYLOS SynCone).6-8 The ANKYLOS system consists of 2 key components: the ANKYLOS tissue care connection, which has been shown to withstand immediate load, with no micromovement or bacterial contamination; and the innovative telescopic design with the titanium tapered abutment and gold cap.9
Four SynCone conical overdenture abutments were placed over the implants, the sizes of which were predetermined by the SimPlant plan and verified with try-in abutments. Utilizing a one-mm hex prosthetic ratchet, the 4 abutments were torqued to manufacturer specifications, 15 Ncm. SynCone gold caps were then placed on the conical abutments, and flexible polymerization sleeves were used to protect the soft tissue.9
To create space for the acrylic to pick up the gold copings, a window was created in the transitional dentures. After vertical dimension of occlusion (VDO) was verified, cold-cure acrylic was mixed and placed in the transitional denture, allowing time for it to polymerize. The transitional overdenture was then removed with a crown-tapping device, trimmed, polished, and reseated in the patient's mouth.9
By using ANKYLOS SynCone technology, the endosseous section of the implant would handle immediate loading, making it capable of fully supporting the restoration because of the conical connection that attaches the abutment to the implant. This would ensure that the patient would not go any amount of time without teeth after the implants were placed.9
Definitive Denture Fabrication
The patient returned to the office after an interim period following placement of the 4 implants in the mandible and delivery of the transitional dentures. During this appointment, a new implant-supported prostheses for the mandible was prescribed. Since he was edentulous on both arches, the patient decided to have the maxillary arch rehabilitated simultaneously with his mandibular arch. Final impressions of both maxillary and mandibular arches were taken using a vinyl polysiloxane material and sent to the laboratory.
|Figure 4. The vertical dimension of occlusion was established with the patient's existing dentures in place, at the position previously marked on his nose and chin.||Figure 5. A bite registration material (Regisil Rigid [DENTSPLY Caulk]) was applied between the indexed wax rims.|
|Figure 6. The models were oriented and sent to the dental laboratory team.|
The dental laboratory team then accomplished the necessary fabrication steps prior to the next appointment. First, the impressions were boxed and poured, then trimmed appropriately, and stabilized record bases with wax rims were fabricated.
During the subsequent visit, the record bases and wax rims were first tried-in to ensure proper fit and comfort.10,11 Necessary adjustments were made for form and function, and the wax rims were contoured to achieve proper lip support, phonetics, and occlusal plane. Once satisfied, a jaw relation was taken and VDO established at the position previously marked on the patient's nose and chin with his existing transitional dentures in place (Figure 4).12 A bite registration material (Regisil Rigid [DENTSPLY Caulk]) was applied between the indexed wax rims and allowed to set at the proper position (Figure 5). The properly oriented casts were then sent to the dental laboratory team for use when setting the teeth (Figure 6).
During previous discussions with the patient, it was established that it was time for an upgrade to his dentures. Therefore, the decision to use Mondial denture teeth was based purely on the patient's aesthetic concerns.
These denture teeth are inorganic nanofilled prosthetic teeth that demonstrate a level of liveliness that's a definite advantage for patient acceptance. Advanced material sciences such as nanopearls impart a high resistance to abrasion to the Mondial teeth, without modifying hardness or elasticity. Additionally, the nanopearl technology contributes to the teeth's tough fracture resistance, similar to shock absorbers. While other denture tooth technologies incorporate one large elastic particle, the Mondial nanopearls are composed of small rubberized particles bound together with the same material used to create the tooth, which results in longer wear resistance.
Whereas most available denture teeth look very unnatural and often lack in aesthetics and form, without the lifelike translucency and blending found in natural teeth, the Mondial anterior and posterior teeth are well designed; anatomically correct from all aspects, including the lingual; and are aesthetically pleasing. The anterior molds clearly have been created with methodical attention to the layering detail. The deep and dentinal material layering produces natural-looking, life emitting mammelon structures that are complemented by the translucent enamel. When the tooth is in its natural environment, the opalescent and fluorescent properties exhibit a very lifelike and natural appearance (Figure 7).
|Figure 7. The denture teeth exhibited aesthetic qualities similar to those of natural dentition.||Figure 8. An example of the customized setup of the teeth with overlapping and rotation.|
|Figure 9. After the teeth were mounted on the articulator, they were set in the wax rims and returned to the office.||Figure 10. The finished dentures were ready for delivery.|
Mondial denture teeth are also robust in design, making them ideal for implant-supported restorations. They are very dense in the center due to high compression in the molding process, displaying no voids or unpolymerized resin that may be occasionally seen in some prosthetic teeth.
Additionally, the use of CAD/CAM technology during the manufacturing process not only results in a very natural looking anatomy and form, but also ensures consistency and precision between molds. Gone are the days of rigid, unnatural, and mechanical looking prosthetic teeth. Another likeable feature when setting the teeth is the lack of an overabundance of flash, which is commonly associated with the molding process. From a technique standpoint, this is advantageous when trying to achieve a natural set-up. Without the associated flash present, the teeth just seem to lay on each other and can be easily positioned by rotating or overlapping, creating a customized setup (Figure 8).
Once the casts were mounted on an articulator, the teeth were set in the wax rims and returned to the office (Figure 9). At the try-in appointment, the proper position of the teeth was verified for form and function, then returned to the laboratory for processing on the final cast. Once laboratory processing was accomplished, the finished dentures were returned for delivery (Figure 10).
Delivery of the Aesthetic Dentures
The dentures were tried in to evaluate proper fit, comfort, and occlusion. With minor adjustments accomplished, the mandibular denture was secured. An intraoral pickup of the retaining element was necessary, and the intaglio of the mandibular denture was modified (Figure 11) to accommodate the ANKYLOS SynCone gold caps. The SynCone gold caps were secured on the abutments and a determination of sufficient clearance was made intraorally.
|Figure 11. The intaglio of the mandibular denture was modified.||Figure 12. The denture was retrieved and inspected for complete pickup.|
|Figure 13. The completed dentures were placed in the patient's mouth.||Figure 14. Preoperative full-facial view of the patient.|
|Figure 15. Postoperative full-facial view of the patient with his definitive implant-supported denture prostheses.||Figure 16. Postoperative Panorex showing ANKYLOS implants with SnyCone abutments (DENTSPLY Tulsa Dental Specialties).|
Auto-polymerizing acrylic was mixed and placed in the modified areas of the mandibular denture. The denture was positioned over the abutment-retained SynCone gold caps, and the patient was instructed to close and hold in full centric occlusion to allow for complete cure of the acrylic material. After approximately 7 minutes, the denture was retrieved and inspected for complete pickup (Figure 12). Excess acrylic was trimmed to remove any sharp edges.
Finally, the mandibular denture was checked in situ for fit and any occlusal change. The delivery of the denture was accepted by the patient (Figure 13), and he was instructed to return in one week to evaluate the prostheses.
Through the use of dental implants and overdenture prostheses, patients now have options beyond the conventional dentures of the past (Figures 14 to 16). With optical and functional qualities that mimic those of natural dentition, along with improved fit and biocompatibility, materials for denture prostheses have undergone significant improvements. By utilizing advancements in CAD/CAM technologies, material sciences, and implant techniques, dentists can provide edentulous patients with the best in artificial dentition, while treating the patient as a whole.
The authors would like to acknowledge George T. Knight, DDS, and Steven Buckley, DDS, MD, for their contributions to this case.
- Fiske J, Davis DM, Frances C, et al. The emotional effects of tooth loss in edentulous people. Br Dent J. 1998;184:90-93; discussion 79.
- Vogel RC. Implant overdentures: a new standard of care for edentulous patients—current concepts and techniques. Compend Contin Educ Dent. 2008;29:270-276.
- Henry K. Q&A on the future of implants. Dental Equipment and Materials. September/October 2006.
- Rossein KD. Alternative treatment plans: implant-supported mandibular dentures. Inside Dentistry. 2006;2:42-43.
- DiMatteo AM. Dentures and implants: bringing them together for a winning combination. Inside Dentistry. 2009;5:96-104.
- Mericske-Stern R, Assal P, Buergin W. Simultaneous force measurements in 3 dimensions on oral endosseous implants in vitro and in vivo. A methodological study. Clin Oral Implants Res. 1996;7:378-386.
- Feine JS, Carlsson GE. Implant Overdentures: The Standard of Care for Edentulous Patients. Chicago, IL: Quintessence Publishing; 2003.
- Adell R, Lekholm U, Rockler B, et al. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg. 1981;10:387-416.
- Shor A, Goto Y, Shor K. Mandibular two-implant-retained overdenture: prosthetic design and fabrication protocol. Compend Contin Educ Dent. 2007;28:80-88.
- Little D. Immediate outcomes: using flapless surgery and Ankylos SynCone overdenture abutments. Inside Dentistry. 2007;3:108.
- Vogel R. Clinical technique to simplify overdenture success. Implant Realities. 2006;1:19-20.
- Lytle R. Vertical relation of occlusion by the patient's neuromuscular perception. J Prosthet Dent. 1964;14:12-21.
Disclosure: Dr. Little reports no disclosures.
Disclosure: Mr. Apparicio writes articles and lectures for DENTSPLY, and receives honoraria for DENTSPLY webinars.
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