strumenti chirugici per impianti dentali realizzazione soprastrutture viti impianto kit chirurgico Primer S.R. Implant

Design of the implant Primer S.R.

The shape of the implant has a slightly conical form in the apical part. This has the purpose of enabling better adaptation to the profile of the bony crest that often features substantial vestibular re-absorption, in particular with reference to the maxillary teeth. The coronal part, on the other hand, is cylindrical, in order to ensure greater primary stability of the implant. The same reason underlies the choice of a threaded fixture.

It has by now been widely demonstrated that one of the greatest critical factors of the success of an implant is primary stability [1-2-3], and that this stability is dependent to a very great extent upon the shape of the implant [3-4-5].

Specifically, the best results mentioned in literature have been achieved with threaded implants [5-6-7]

 

Functions of the thread:

• It increases the surface area of contact between the bone and the implant

• It transforms lateral stresses (poorly tolerated by the implant) into vertical forces featuring an apical pattern (the most easily tolerated) thanks to the support provided by the turns.

• It increases retention and primary stability substantially thanks to the self-tapping introduction procedure [5]

• It improves the bone quality, thanks to the action of compressing and condensing of the bone tissue exercised by the turns during screwing [6-7].

Special attention has been paid to investigating these points, with reference also to the possibility of immediate loading. Since the literature mentions an optimum screwing torque varying between 32 and 40 n/cm [8], below which stability is not 100% guaranteed and above which the response of the bone tissue would not seem to be favourable, it was decided to design the thread in two separate sections.

The turns are therefore close together and not very marked in the area intended to engage in the cortical bone. Here, on the average, the tissue will be compact and not require condensing, so that with a good grip it will provide excellent anchorage. The turns are farther apart and more marked, on the other hand, in the area of the implant that will be sunk into the cancellous bone, where compression and condensing are often useful and in which safe anchoring is definitely facilitated by wider turns.

On the neck of the implant, which is not threaded [9] and has a height of 0.5 mm, the apical half is treated while the coronal half is machined.

The choice of this compromise was determined by the advisability of maintaining a biological width as close as possible to the physiological width above the emergence of the implant, limiting offsetting bone resorption processes as much as possible but without losing sight of the need for optimum aesthetic results. This latter consideration often induces the surgeon to sink the implant deeper into the bone, above all in the frontal sectors.

 

Bibliography

1-Donath K., Laass M., Gunnzl H. J.: The histophatology of different foreign-body reactions to oral soft tissue and bone tissue. Virchows Achive A Pathol Anat 1992 ; 420 :131-137.

2- Brunski J.B.: Influence of biomechanical factors at the bone-bio material interface in Davies JE (Ed ) The bone-biomaterial interface, Toronto University press, Toronto 1991 ;391-405

3- Brunski J.B.,Biomechanical factors affecting the bone-dental implant interface: Review paper 1992; Clin Mater ; 10:153-201

4- Szmuklwe-Moncler S., Salama H., Reigerwirtz Y., Dubruille J.H.: Timing of loading and effect of micromotion on bone-dental implant interface:review of experimental literature. J Biomed Marer Res (Appl Biometer ) 1998;43:192-203.

5- Degidi M., Scarano A., Petrone G., Piattelli A., Histologic analisis of clinically retrived immediately loaded titanium implants: a report of 11 cases. Clin.Implant Detistry and Related Asearch 2003; vol. 5, n.2: 89-94.

 

6-Skalak R.: Biomechanical consideration in osseointegrated prostheses.J Prothet Dent 1983; 49:843-848

 

7- Wolf La, Hobkink JA.: Bone response to a matched mondulus endosseus implant material. Int J Oral Maxillofac Implants 1989;4: 311-320

 

8- Degidi M., Pattelli A.: immediate functional and non functional loading of dental implants: a 2- to 60 - month follow - up study of 646 titanium implants J. Periodontal,feb. 2003 ; 225-241

 

9- Petrie CS, Williams JL: ‘Comparative evaluation of implant designs: influence of diameter, length, and taper on strains in the alveolar crest. A three-dimensional finite-element analysis’; Clin Oral Implants Res, 2005 Aug; 16(4):486-94.

 

10-Piattelli A., Corigliano M., Scarano A., Quaranta M.: Bone reactions to early occlusal loading of two-strage titanium plasma - spraved implants: a pilot study in monkeys;Int J Periodont Rest Dent 1997; 17: 163-169.

 

11-Surface chemistry effects of topographic modification of titanium dental implant surfaces: 1. Surface analysis. Morra M. Cassinelli C. Bruzzone G. Carpi A. Di Santi G. Giardino R. Fini  M. NobilBio Ricerche Villafranca d’Asti, Italy Int. J. Oral Maxillofac. Impants 2003 Jan Feb; 18 (1): 40-5. 

 

12-Surface chemistry effects of topographic modification of titanium dental implant surfaces: 2. In vitro experiments Cassinelli C. Morra M. Bruzzone G. Carpi A. Di Santi G. Giardino R. Fini  M. NobilBio Ricerche Villafranca d’Asti, Italy