Improving Quality of Life Using Removable and Fixed Implant Prostheses

Clinical Case Overview

Patient History and Chief Complaint: A 61-year-old man initially presented in 2007 with a chief complaint of wanting better speech and an improved appearance for his job (Figure 1). He reported using “a lot” of adhesive to gain stability for his partial dentures, which also rubbed his tissue raw (Figure 2). He stated that he had multiple root canal failures in the past and was not interested in saving any teeth that would require another root canal. The patient had no known medical contraindications to dental treatment and his medical history was noncontributory. He expressed concern about the cost of his own dental care while also handling medical costs for his wife’s cancer treatments. At that time, tooth No. 29 was extracted to relieve the pain from a periapical abscess. He returned 2 years later, after losing his wife to cancer, with the desire to develop a lifetime strategy for improved dental health.

Diagnostic Findings

Periodontal: The examination revealed light to moderate bleeding upon probing and no probing depths greater than 4 mm. Radiographs revealed generalized moderate horizontal bone loss (Figure 3). The diagnosis was AAP Class II, mild periodontitis.

Risk: Moderate
Prognosis: Fair

Biomechanical: Upon clinical examination, several posterior direct restorations were found to be in questionable condition. There were multiple areas of interproximal carious lesions, and active caries was noted both clinically and radiographically (Figure 4).

Risk: High
Prognosis: Poor

Functional: The temporomandibular joints were asymptomatic and there was no history of clenching or grinding. The two remaining maxillary teeth were noted to have a Class I mobility. A diagnosis of primary occlusal traumatism was indicated because the increased mobility resulted from too few remaining teeth for chewing. The patient was diagnosed with dysfunction.

Risk: Moderate
Prognosis: Fair

Dentofacial: The patient had high lip dynamics, which were masked by a guarded smile. He had realistic esthetic demands for the final prosthesis.

Risk: Moderate to High
Prognosis: Fair

Treatment Goals and Options

The following treatment goals were determined:
• To manage caries and reduce biomechanical risk
• To improve speech and enunciation
• To improve appearance by replacing missing teeth and altering tooth position
• To create an acceptable therapeutic occlusion

Several options were outlined for the patient.

Option 1: Restore the remaining dentition for support and retention of the removable prostheses. The existing teeth would be treated with endodontic therapy as needed and restored with cohesively retained full-coverage restorations. Several barriers to this approach included management of the esthetics of the clasps on the removable prostheses, questionable sound tooth structure with subgingival decay on the root surfaces, and poor long-term prognosis of remaining teeth because of the patient’s high risk for decay. These barriers lead the patient to decline this option. Saving any or all of the remaining teeth would keep the biomechanical risk high and if teeth were lost in the future, the fit of the removable prosthesis would be compromised and additional costs incurred.

Option 2: Restore the remaining dentition for support of the removable prostheses and use implants to aid in retention. This option consisted of all of the treatment included in Option 1 along with implants being placed to assist in retention of the removable prostheses without clasps to improve esthetics. Implant-retained removable partial dentures (RPDs) can be used to spread a complex treatment over time, thus increasing the physical and economic chances of success.³ The patient disliked the idea that one or more of the remaining high-risk teeth could still fail and compromise the entire case. This option also carried with it the potential for additional dentistry and costs as the patient entered his retirement years.

Option 3: Extract all the remaining teeth and use implants to support and retain the fixed and removable prostheses. This choice was the one that was most in line with the patient’s goals and concerns. When reviewing the treatment options and associated implant risks, the patient had been adamant about not having any endodontic therapy and did not want to accept the associated risk of saving the remaining dentition. He was happy to know that, with implants, he would never have to worry about a “cavity” for the rest of his life. The patient’s goals for the maxillary dentition were to eliminate using adhesive and having greater security when speaking in public. The patient wanted more of a fixed restoration on the mandibular dentition to avoid the difficulties he had heard were involved in wearing lower dentures.

The authors honored and respected this patient’s willingness to lose his long-fought battle to keep his teeth in return for the hope of restoring his quality of life with a new prosthesis. This option met the patient’s expectations by reducing the biomechanical risk of the remaining dentition and increasing the esthetic outcome by eliminating the need for clasps. Such shared decision-making is designed to improve outcomes such as satisfaction, cooperation, and compliance.⁴

Treatment Plan

A complete history that includes questions about levels of masticatory function and impact of existing dentures on quality of life becomes important when treatment planning the edentulous patient for restorative care.⁵ Treatment decisions in this case were centered on lowering the patient’s biomechanical risk to improve the long-term prognosis. Whenever possible, treatment decisions that lower risk are always preferred over those that increase risk.⁶ The treatment plan consisted of extracting all the remaining teeth and placement of implants to support the prosthesis.

In implant dentistry, the first determination is selecting a prosthesis that will satisfy the patient’s needs and desires and optimize results.⁷ This may range from a completely fixed prosthesis to one with primarily soft-tissue support.⁷ Once the final prosthesis has been decided, the required size, number, and location of abutments necessary to satisfy the prosthodontic requirements can be established.⁷ The final restorations in this case consisted of a maxillary removable, implant-assisted denture and a mandibular screw-retained, fixed, implant-supported prosthesis. The patient elected to use a removable prosthesis in the maxillary arch to avoid sinus augmentation surgery and to stay within his dental budget. It was decided that the best location for the implants would be the maxillary region anterior to the sinus and the mandibular region anterior to the mental foramen.

Treatment Phases

Phase I: Tooth position analysis and laboratory fabrication of the transitional prostheses. Preoperative photographs and mounted study casts were used to determine ideal tooth position and facilitate changes made in the laboratory prior to prosthesis delivery (Figure 5). The preoperative vertical position of maxillary central incisors were lengthened 1 mm in the transitional prosthesis to show 1 mm to 2 mm of the incisal edge of teeth Nos. 8 and 9 with the lips at rest and to follow the curvature of the lower lip. Tooth No. 11 was shortened to achieve the end result of making the maxillary arch level in all three planes. The existing horizontal position was acceptable and duplicated. The vertical position of the lower incisal edge displayed 4 mm of tooth with the lips at rest and was moved apically 2 mm to achieve an end result of 1 mm to 2 mm reveal at rest (Figure 6). In addition to placing the teeth into a more ideal esthetic position in the face, the overbite was decreased and the incisal guidance flattened for a more favorable therapeutic occlusion. An immediate full upper transitional denture and a lower acrylic partial were fabricated prior to the surgical appointment.

Phase II: Extractions, implant placement, and transitional prosthesis. Due to the patient’s anxiety and fear, he elected to have Phase II accomplished utilizing intravenous conscious sedation. Minimally invasive extractions preserving the alveolar socket and bone were performed on teeth Nos. 20 through 22, 27, and 28. After curetting and irrigating, the sockets were prepared with drills for immediate implant placement. In all five osteotomies, 4-mm x 13-mm implants (OsseoSpeedTM, Astra Tech Inc., www.astratech.com) were placed with even spacing anterior to mental foramen⁸ (Figure 7). Multi-unit abutments were placed on each of the mandibular implants and torqued to 30 Ncm followed by placement of open-tray impression copings (Figure 8). The mandibular transitional acrylic partial was placed in the mouth using the wire clasp on the molars for orientation (Figure 9 and Figure 10). Impression material was delivered intraorally around the impression copings to accurately record the position of the implants. The impression copings were relined in the acrylic partial with self-cure acrylic in the laboratory using an indirect technique (Figure 11 and Figure 12). After contouring, polishing, and removing the wire clasp, a transitional, acrylic, fixed screw-retained, immediate-load mandibular prosthesis was delivered and torqued to 10 Ncm (Figure 13). Teeth Nos. 6 and 11 were extracted and a buccal onlay allograft was performed in the maxillary arch to increase the bucco-lingual width of the alveolar ridge.⁹ An immediate maxillary transitional denture was delivered with a tissue-conditioning material (Hydro-Cast^®, Sultan Healthcare, www.sultanhealthcare.com) to accommodate soft-tissue changes and healing.

Phase III: Tissue conditioning, bone maturation, and occlusal equilibration. The patient was seen 2 weeks after the surgical appointment for tissue conditioning and once per month thereafter to maintain ideal lingualized occlusion and tissue health. At these appointments, necessary denture borders were adjusted and tissue-conditioning material was placed to maintain optimal tissue adaptation during soft-tissue changes and to maintain adequate suction of the maxillary denture. The occlusion was refined to maintain bilateral equal intensity contacts with the maxillary lingual cusp and posterior chewing block of the mandibular fixed transitional prosthesis (Figure 14). The onlay bone graft was allowed to heal for 6 months.⁹

Phase IV: Tissue conditioning, maxillary implant placement, and healing. After 6 months of healing and bone maturation, the maxillary implants were placed. The patient was very satisfied with his appearance and his increased ability to chew properly with the transitional prosthesis during this time. He reported using a small amount of adhesive in the upper on occasion for added security during public presentations. In teeth position Nos. 4 and 13 osteotomies, 4-mm x 11-mm implants (OsseoSpeed), and in Nos. 6 and 11 osteotomies, 4-mm x 13-mm implants (OsseoSpeed) were placed parallel to each other in the maxillary arch, anterior to the sinus. A two-stage approach was used to allow for integration of the implants and to eliminate any chance of occlusal load or stress from the removable transitional prosthesis.¹⁰ Tissue conditioning was performed on the maxillary denture to adapt to surgical tissue changes.

Phase V: Tissue conditioning, maxillary implants uncovered, and placement of locator abutments. Several relines of the upper transitional denture with tissue-conditioning material were necessary over the 6-month healing period of the maxillary implants to accommodate soft-tissue healing and changes. The maxillary implants were uncovered using a crestal incision, and locator abutments (Zest Anchors, www.zestanchors.com) were placed at minimal tissue height to provide maximum thickness of prosthesis. Tissue-conditioning material was placed in the upper denture for ideal adaptation to tissue. Tissue maturation in the upper arch was allowed to heal for 3 weeks prior to denture impressioning.

Phase VI: Maxillary denture impression and mandibular screw-retained fixed implant-supported prosthesis impression. Intraorally, an anterior stop was placed with composite behind the central incisors and a repeatable position in centric relation was recorded with a polyvinyl siloxane (PVS) bite registration (Figure 15). A facebow was taken with the Kois dento-facial analyzer (DFA) facebow system. Functional impression material for tissue conditioning accurately recorded all the soft-tissue landmarks and allowed the upper denture to serve as the final impression. The mandibular transitional prosthesis was removed and adhesive was placed on the intaglio surface before being delivered back into the mouth. A light-body polyether impression material was then placed intraorally between the transitional prosthesis and tissue to record the new gingival tissue height. The impression was removed from the mouth and lab analogs were placed on the impression copings used in the transitional mandibular prosthesis to record implant positioning. This was poured in stone to create the mandibular master cast. The maxillary and mandibular master casts were mounted on an articulator with the centric bite registration. A putty matrix was fabricated to record maxillary and mandibular tooth position for the laboratory to fabricate a milled lower titanium framework and return for prosthesis try-in of the teeth positioned in wax (Figure 16). At the next appointment, the maxillary and mandibular prostheses were placed in the mouth to verify fit of the framework and obtain the patient’s esthetic approval. A new centric relation bite registration was taken to verify the mounting was accurate.

Phase VII: Delivery of maxillary and mandibular prostheses. The maxillary denture was placed in the mouth, and adequate relief was confirmed over the implant attachment housings. Pink acrylic was used to capture the female attachments in the maxillary denture (Figure 17). Cotton rolls were placed between the upper and lower teeth to put the prosthesis under the load of a firm bite. The lower prosthesis was delivered, the implants were torqued to 30 Ncm, and the access holes were filled with a composite resin. The posterior centric contact points were designed using lingualized occlusion, with the maxillary lingual cusp occluding in the central fossae of the mandibular teeth.¹¹ Bilateral equal intensity contacts upon chewing and swallowing were achieved (Figure 18).

Phase VIII: Extraction of remaining molars. The patient elected to have the remaining molar teeth extracted due to being satisfied with the chewing ability of his new prosthesis. Under occlusal load of the upper prosthesis, the lingual cusps of the mandibular molars had fractured from unsupported tooth structure. The patient’s satisfaction with his new prosthesis and the discomfort that had developed from the broken teeth influenced his decision to extract the mandibular molars.

Conclusion

Removable and fixed implant-retained prostheses have given the restorative dentist options to significantly improve speech, esthetics, and function to enhance the quality of life of patients. In this case, the patient reported the increase in chewing ability as his highest source of satisfaction, though it was not his perceived chief outcome sought in the beginning of treatment. He stated there is nothing he is unable to eat and is enjoying the tight fit and security of his dentures without using denture adhesives (Figure 19). Shared decision-making, along with the necessary technical skills needed to fabricate a functional prosthesis, offers dentists the opportunity to have a positive impact on their patients’ quality of life.

Acknowledgment

The authors would like to thank John Zarb, CDT, and Stacy Cribbs for their laboratory support.

About the Authors

Jeff Pennington, DMD
Private Practice
Jacksonville Beach, Florida
St. Marys, Georgia

Sid Parker, DMD
Private Practice
Jacksonville Beach, Florida
St. Marys, Georgia