Lower arch protocol with Arcsys Frictional Implants and Components

AUTHORS: Prof. Dr. Rogério Goulart da Costa Prof. Rafael Cury Cecato Prof. Thiago Roberto Gemeli.

RECORD
52-year-old female patient.

COMPLAINT
Discomfort of the removable total prosthesis and search for better aesthetics and function.

ANAMNESIS
Patient who had been edentulous for more than 30 years with a good state of general health. Complementary evaluation indicated aptitude for surgical procedure.

PLANNING
Substitution of the total lower prosthesis according to protocol. The difficulty to evaluate the best positioning for the implants to the emergency tracks of the intermediate pieces lead to the use of Arcsys. The system allows for the angular refinement which allows for the desired parallelism for the better fitting of the prosthesis with multiple supports.

INTRODUCTION
Since their introduction by Branemark, dental implants have been widely used to rehabilitate edentulous patients1;2, contributing to a significant improvement of the life quality of those individuals. Presently, among all the proposals for rehabilitation of patients that are completely edentulous, the hybrid prosthesis of the “Branemark protocol” type, similar to that suggested in the 60’s is still one of the most used, in face of the evident advantages in relation to the cost/ benefit ratio provided by that technique.

Such procedure consists in supporting a total prosthesis on implants anchored in bone tissue and demonstrates high success rates3;4;5, if determined requirements are respected and the patient is oriented adequately. Those requirements are: adequate initial stability (for immediate load), passivity, lever arm compatible to the anchorage, appropriate hygiene possibility.

For the aesthetics of the final piece, and the hygiene possibilities for the patient not to be compromised, it is essential that the accesses to the screws are located in an area between the occlusal/incisal of the teeth and the lingual/palatal edge of the prosthesis. However, if the implant, for any reason, is not at its ideal inclination, the use of an angled intermediate piece, so as to correct the angulation, is crucial for the professional to achieve the results mentioned above. Besides, using angled intermediate pieces in those situations, it is noticed that the distribution of masticatory forces is favored, in comparison to the use of a straight intermediate in the same scenario.6 The use of components angled up to 20 degrees seem to be within the limits of tolerance of the bone tissue7, suggesting that this will not be the cause of reabsorption around the implant/component. Also, there seems to be no significant difference between straight and angled components in relation to rotation, deflection and the necessary torque to unscrew.8

However, the use of pre-angled components is not the first option of the professionals, which can be explained by the greater difficulty in handling, the risks of aesthetic loss and probable lower mechanical resistance.

For that, the Arcsys Implant System offers the possibility to customize the angulation of the prosthetic components, without, however, implying in inherent losses usually found in pre-angled components. The only thing needed is to customize the direction of the component immediately before its activation, according to the demonstration that follows.

CASE REPORT
52-year-old female patient, user of total upper and lower dental prosthesis since age 18, searched for treatment because she was not satisfied with the lower prosthesis’ instability. The last change of pieces had been done 3 years ago and the soft tissues were healthy (Fig. Initial). That way, the proposal was for a rehabilitation
with Branemark protocol prosthesis for the lower arch and, in a near future, the same treatment for the upper arch. The clinical exam revealed good general health conditions. However, for confirmation, complementary exams were requested: complete hemogram, fasting glycemia, coagulation, prothrombin and glycated hemoglobin.

The tomographic exam of the region in question revealed good bone quality and quantity for the installation of dental implants (Figures 01 to 03). As the prosthesis showed adequate aesthetic
function and maintenance of OVD, a multifunctional guide was made using the duplication of the lower prosthesis (Figures 04 and 05). The surgery was carried out with the installation of 5 Arcsys implants measuring 3.8x11mm that had primary stability of 45N, oriented by the multifunctional guide (Figures 06 to 12). In the sequence, the Angle Referrers were positioned for the evaluation of the need for angulation, when it was noted that only one of them needed folding (Figures 12 to 15). According to the depth of the implants and thickness of the mucous tissue 2.5mm transmucous Arcsys abutments for screwretained restorations were selected, installed and activated (Figures 16 and 17).

Following that, Arcsys Multifunctional Impression Caps were positioned, screwed and united with acrylic resin (Fig. 19). The molding was made with polyether based molding material and the interocclusal record was complemented with acrylic resin over the multifunctional guide (Fig. 19). The total lower prosthesis itself was used for making the temporary prosthesis, being united to other multifunctional impression caps (working as a temporary coping) with self-polymerizable acrylic resin (Fig. 20).

The analogs were positioned in the impression mold, screwed and sent to the laboratory for the manufacture of the protocol bar. In 48 hours, the bar was tested for fitting and passivity. The next day, the final prosthesis was fitted and installed (Figures 21 to 23).

FINAL CONSIDERATIONS
Arcsys Implants allow for great versatility for rehabilitation treatments for having an innovative feature in an implant system: the possibility for the dentists or prosthetic technicians to fold the intermediate pieces themselves, allowing for better planning and, consequently, better predictability for the success of the treatment.