A Modified Method of Immediate Occlusal Loading Using a Reinforced Framework Denture: A Case Report

According to the original protocol, Bränemark implants require a 2-step surgical procedure in order to become osseointegrated. The 2-stage surgery is sometimes uncomfortable for the patient. In addition, recent research has shown that osseointegration can also be achieved with a one-stage technique (with early or immediate implant loading in good quality bone) which simplifies and shortens treatment for the patient’s benefit.1
Implant stability follow-up of a patient receiving immediate implant-supported full-arch rehabilitation in both jaws, and evaluation of the patient’s acceptance for this kind of rehabilitation have been reported on in the literature2,3; showing that a slightly staged approach for full-arch rehabilitation in both jaws using immediate implant loading protocols is a realistic treatment option.
Immediate loading of dental implants in completely edentulous patients is receiving great attention. Standard surgical protocol is used with primary stabilization of the implants as a goal.4 The restorative dentist must work together closely with the surgeon and the laboratory technician to make immediate loading a reality for the completely edentulous patient.5 This article describes a technique developed to fabricate an immediately loaded fixed-detachable prosthesis using a reinforced framework denture.

CASE REPORT

A 57-year-old white male, wearing maxillary and mandibular dentures, presented with a complaint regarding a lack of retention in his mandibular prosthesis during speech and mastication. In the clinical examination, an implant-supported prosthesis was discussed with the patient, explaining the benefits that would be achieved with this possible solution. The patient then consented to the proposed treatment plan.

Figure 1. Waxed mandibular denture and surgical guide.	Figure 2. After acrylic resin (SR Triplex Hot, Ivoclar Vivadent) polymerization, the implants’ drilling location remained well-characterized.
Figure 3. Initial drilling using a clear acrylic resin surgical guide to establish implant placement.	Figure 4. Sandblasted (50 µm aluminum oxide) copings in place.
Figure 5. Surgical wound was protected by rubber dam. Cotton was used to occlude the openings in the copings.	Figure 6. The mandibular prosthesis in place over the rubber dam.
Figure 7. Dentures in place with minimal occlusion pressure to capture the copings in the mandibular prosthesis.	Figure 8. The definitive prosthetic appliances.

Conventional maxillary and mandibular prosthesis were built, and aesthetic and functional verifications were conducted. The waxed mandibular prosthesis was duplicated with irreversible hydrocolloid (Hydrogum [Zhermack]) and a mucosa-supported surgical guide was fabricated with self-curing clear acrylic resin (Clássico [Artigos Odon-tológicos Clássico]).
The implants’ location and length were determined based on panoramic radiograph measurements. (This will be briefly discussed later in the article.) In the area of the functional cast corresponding to the residual ridge, the points where the implants would be inserted were determined. A transparent surgical guide was used to drill the model in demarcated points. These perforations were then transferred to the waxed mandibular denture and polymerized (Figure 1).
It should be noted that the perforations corresponding to the implant location were filled with a C-silicone laboratory rubber (Zetalabor [Zhermack]), to maintain the spaces after processing. These references also served as a basis to determine the reinforced framework contours, so that they would not interfere with the implants’ insertion axis. After acrylic resin (SR Triplex Hot, Ivoclar Vivadent) polymerization, the implants’ drilling location remained well characterized (Figure 2). Finally, the mandibular (and maxillary) prostheses were finished and polished.
All surgical techniques followed a protocol that respected the patient’s health, safety, and welfare; as indicated by the dental examination, medical history, and general diagnosis. Using the clear acrylic surgical guide, initial drilling was performed on the alveolar ridge to establish placement of the implants (Figure 3). A crestal incision was made and a mucoperiosteal flap was raised at both the labial and lingual aspects to enable better visualization and correct location of the sockets. Drilling was performed using a sequence of drills with increasing diameter under constant irrigation. Two posterior external hex ultra (4.1 and 10 mm) self-tapping treated surface implants (4.1 and 10 mm length) (S.I.N. [SIN Implant Systems]) and 3 interforaminal anterior external hex ultra (4.1 and 13 mm) self-tapping treated surface implants (S.I.N. [SIN Implant Systems]) were used. Inser-tion torque was measured with the aid of the drilling unit, and with a manual torque wrench at a minimum of 45 Ncm.
After placement of the implants, the abutments were installed at 20 Ncm torque. Copings, fabricated in the laboratory previously and sandblasted (roughened) with aluminum oxide (50 µm), were placed and made ready to be captured in the denture with a self-curing acrylic resin (Figure 4). The surgical wound was protected by a custom-cut piece of rubber dam and small cotton balls were used to close the (occlusal) openings of the copings (Figure 5). The perforation opening was necessary to provide that there would be no interference during dentures installation (Figure 6). Next, self-curing acrylic resin (PATTERN RE-SIN LS [GC America]) was placed in the denture perforations, and the dentures were placed. The patient was asked to keep his mouth closed with minimal occlusal pressure (Figure 7).
Once polymerization of the self-curing resin was completed, the mandibular denture was removed. The lingual and buccal flanges were then adjusted, finished, and polished. After the polishing procedure, in the definitive installation, the prosthesis screw torque was 10 Ncm. Finally the access openings were sealed with a light-curing resin (Filtek Z350 [3M ESPE]) which completed the prosthesis (Figure 8).
An occlusal adjustment procedure was performed based on bilateral balanced group guidance to bring greater stability to the maxillary denture. The patient was given postoperative instructions regarding initial care, alimentation, and the cleansing and maintenance of his new prostheses.

DISCUSSION

The original Bränemark protocol for dental implant treatment was based on submerged healing prior to loading. In recent years, immediate functional loading has been reported to be possible with a high success rate for various indications. This includes using several splinted mandibular implants to support a fixed prosthesis. However, time spent in the dental laboratory for the metal work, achieving framework passivity, transfer molding, and articulator mounting are all factors that can make the work slower.
The technique described proposes fabricating a bar-reinforced denture before the implants are inserted, followed by immediate attachment with self-curing acrylic resin. Thus, the time spent is lower and the operation less tiring. The cost becomes more reasonable and can allow for the treatment of a larger number of patients.
In addition to the technique described above, referring to prosthesis with posterior implants, this protocol can be well applied in interforaminal implants as well. However, the thickness of the bar should not be neglected, so that the cantilever resists the forces of mastication.
Although this is a low cost technique, there is a disadvantage related to this treatment protocol. The greatest limitation is the lack of information available from panoramic radiographs concerning the thickness of the alveolar ridge. When treatment planning is not possible with the use of only a panoramic radiograph, more accurate imaging should be used. This will obviously increase the costs for the patient. However, careful selection of cases with proper diagnosis and treatment planning can result in success.

SUMMARY

The technique presented in this article presents a protocol for treatment that reduces the time required for the fabrication and placement of an implant supported prosthesis. It also offers improved patient comfort at a lower cost when compared to conventional technology.

References

1. Turkyilmaz I, Tözüm TF, Tumer C, et al. A 2-year clinical report of patients treated with two loading protocols for mandibular overdentures: early versus conventional loading. J Periodontol. 2006;77:1998-2004.
2. Portmann M, Glauser R. Report of a case receiving full-arch rehabilitation in both jaws using immediate implant loading protocols: a 1-year resonance frequency analysis follow-up. Clin Implant Dent Relat Res. 2006;8:25-31.
3. Ostman PO, Hellman M, Wendelhag I, et al. Resonance frequency analysis measurements of implants at placement surgery. Int J Prosthodont. 2006;19:77-83.
4. Attard NJ, Zarb GA. Immediate and early implant loading protocols: a literature review of clinical studies. J Prosthet Dent. 2005;94:242-258.
5. Achilli A, Tura F, Euwe E. Immediate/early function with tapered implants supporting maxillary and mandibular posterior fixed partial dentures: preliminary results of a prospective multicenter study [published correction appears in J Prosthet Dent. 2008;99:167]. J Prosthet Dent. 2007;97(suppl):S52-S58.