PREFACE - MULTI-TYPE ELECTROWELDED IMPLANTS

This term is used to describe an implantological technique that complies with modern trends of surgery which is gradually becoming less invasive every day. This means less suffering for the patient who also has the advantage of immediate functional benefits.

The adjective "multi-type" refers to the fact that the operator can choose from a wide range of implants with different shapes, lengths and calibre.
This enables the structure of the implant to be adapted to the patient's anatomical characteristics. It does not require preparatory surgery which sometimes involves bone grafting techniques from other anatomical districts.

The atraumatic nature of multi-type electrowelded implantology makes it the preferred technique of first choice, reserving more invasive techniques as second choice - only to be used in the event of failure.
Depending on the characteristics of the specific type of implant used, its immediate or long-term failure will result in small lesions to the bone apparatus, but following spontaneous repair it can be re-utilised after a short interval.

Welding the implants together also leads to a different mode of distributing the stresses acting on the structure which no longer acts as individual implants and instead participates in a joint effort providing mechanical support for the prosthesis.
The most immediate concept when attempting to imitate the function of an organ is to imitate its form and structure. In practice, however, this is not possible.
Therefore, when attempting to reproduce the tooth it is natural to use the concept of tooth - monoimplant.
But how would an engineer attempt to make up for the lack of gomphosis?
This is a system that perfectly absorbs the functional stress in completely healthy conditions.
This mechanism is absolutely necessary not only as a means of discharging stress, but also to compensate for geometric and structural alterations undergone by the jawbone. All this constitutes a mechanical system comprising the "prosthesis implant structure - bone".
The three units are all subject to occlusal stress and each reacts in its own way.


However, the individual reactions must interact with one another.

A) The prosthesis must comply with:
Ante's Law = the overall radicular surface of the posts must be equal or greater than the presumed surface of the replaced teeth.
The flexion and curve of the beam are proportional to the cube of its length and inversely proportional to the cube of its thickness. A bridge beam is subject to bending stress whatever its length. The thrusts transmitted by the intermediate elements to the dental posts differ in intensity and direction from those imposed by single reconstructions. The transfer stresses exerted on a means of anchorage have a medio-distal direction, whereas they are vestibular-lingual on an isolated element.
Even the discharge of the stress vectors without apparent movement provokes the same effects leading to the perimplant conoid degeneration of monoimplants.
 Bone regeneration surgery is itself confirmation of the inadequacy of this method. This technique is not required when electrowelded structures are used


B) The mandibular bone can be thought of as a box-type girder with a perimetral structure reinforced by thickening (Mylohyoid lines) and containing cancellous bone reminiscent of a honeycomb structure.

This complex is not rigid but is subject to elastic deformations that are discharged on the implant, which cannot absorb them because it lacks any natural suspension in the form of gomphosis.

Therefore, given that no prosthetic artefact can transmit the stress to the bone structure in an absolutely axial manner, and given that the monoimplant structure lacks any physiological absorption, a discrepancy is created between the flexion of the bone and the rigidity of the implant. On the contrary, in dentures mounted on electrowelded implants the implant complex acquires an adaptability that, like reinforced concrete structures, can follow the flexibility of the underlying bone.
This occurs without disturbing the balance of the transition section at the cortical level (the latter's conoid collapse has never been reported). Owing to its construction method, resting on a monobloc structure in which there is practically no interimplant diastema (namely the distance is so small it can be said to be zero), the prosthesis discharges the stresses without bending.
It is the deep implant structure that follows the bone modulus of elasticity.
The intraoral welding process is completely innocuous and, based on research by Prof. Mondani, it is performed using a microwelder that acts on the titanium structures using a process of crystal compenetration without the need for other metal. This process is known as syncrystallisation.
Preliminary studies which are now being expanded, carried out at the Department of Biomechanics at Turin Politecnico, highlight the maximum concentration of tensions at the emerging neck of the implant. This fact is confirmed by the clinical observation of the cone of cervical resorption in all unwelded implants, including both the so-called "osteointegrated" and "traditional" models.
This clinical syndrome is not found around electrowelded structures, confirming the hypothesis of a better distribution of stress. These techniques can therefore be used to bypass anatomic districts that would otherwise contraindicate the use of dentures on implants.
This makes it possible to treat both mandibles with severe resorption and upper jawbones with highly developed sinuses.
The use of metal-ceramic dentures allows optimal cosmetic results to be achieved together with maximum respect for the periodontal structure. It is not necessary to use resins or other materials to achieve the isodromic adaptation of the prosthetic apparatus.
The use of gauged connecting bars allows suitable structures to be created for the anchorage of overdentures that do not require further interventions by dental technicians, resulting in marked savings for the patient. The long follow-up of this method confirms the brilliant immediate and long-term results (more than 30 years).
However, this should not be confused, as unfortunately occurs, with similar techniques based on completely different biomechanical principles, for which we feel that the term "obsolete" used pejoratively by those who are not familiar with it should be cancelled and replaced by the more precise "tested".
Pasqualini's blade inserted for 20 years. Quadrant of pins inserted for 10 years. Quadrant with bracket inserted for 1 year.
I would like to express my warmest thanks to my friend and colleague Marco Pirovano, witness to a glorious past and artificer of scientific progress.