The aesthetics of Italian ‘one piece’ implants with immediate loading in the frontal areas

Immediate loading subjects the peri-implant bone to two simultaneous activities: functional activity and tissue healing. The latter will evolve in a reparative sense (osseointegration) in the presence of adequate loading (1). The principles and techniques used for immediate loading provide for a range of highly complex operations depending on the different anatomical situations. Following the surgical protocols of the Italian school, immediate loading provides functional results and aesthetic results similar to natural teeth, which are often better than those obtained with the deferred loading implant technique (2). The best expression of the spread of this implantology method was the international and national congresses of the GISI (Italian Group for Implant Studies), founded and directed by Professor Giordano Muratori from 1970 to 1997. The world’s most prestigious scholars participated in the GISI congresses, the proceedings of which have been published (3). Its study and evolution are kept alive by other scientific associations (AISI and Nuovo GISI). According to the Italian method, immediate loading has more than half a century of clinical history and follows a codified protocol (4,5).

MATERIALS AND METHODS

The progenitor of the one-piece implant is the 1964 titanium screw by Stefano Tramonte (the first person in the world to use titanium in dentistry) (6,7). This implant certainly belongs to historical implantology, but also the current practice, and is specific for immediate loading because of some of its characteristic requirements, which are:

• the ability to anchor itself firmly to the bone and achieve good primary stability, thanks to the wide loop;
• the ability to adapt to the pre-existing native bone, without the need to modify it;
• the possibility of being parallelized directly in the mouth to allow for insertion in the most favorable bone direction. Italian single-block implants are made of grade 2 titanium to facilitate parallelization maneuvers;
• the feature of having an abutment with a smaller diameter than the part intended to be immersed in the bone (fixture). This is the platform switching concept that has also been adopted by more recent implant systems. But unlike biphasic systems without any micro gap (8, 9).

For immediate loading, the largest surface area in contact with the bone (large loop), maximum mechanical anchorage (maximum depth and maximum screw pitch compatible with bone density) are recommended. The implant should be as long as possible concerning the amount of bone available. Still, its width will depend on the quality of the bone as well as the thickness of the available bone: the denser and thinner the bone, the narrower the core and width of the loops; the less dense the bone, the wider the core and width of the loops. In severe atrophies, any supporting implants, such as titanium needles, will adapt to the existing bone morphology and will be welded intra-orally during surgery to the main implant. The insertion axis should allow for the greatest possible length of each implant under the need to observe the ideal loading axis for single implants or the resultant of the axes for bipods, tripods, or multiple insertions (10-13).
The divergence of the endosseous implant bodies allows for greater stability under load. Finally, the insertion axis should, wherever possible, allow for bicorticalism. Each implant inserted must guarantee maximum bearing capacity in the site chosen for its insertion.

Inserting angled implants, either in the mesiodistal sense or in the vestibular-palatine or vestibule-lingual sense, makes it possible to widen the bearing base and acquire greater primary stability. The creation of bipods and tripods (implant complexes consisting of two or three implants with endosseous parts diverging from each other and emerging stumps united in a single body) can be achieved with multiple insertions in the same place or with close diverging insertions using the various types of implants.
In the case reports presented, one-piece titanium implants of the following types were used: Tramonte screw, ‘Garbaccio bicortical screw’ (IT patent 1972, US patent 1983) with a loop diameter of 3.5 and 4.5 mm, MUM mini-implant with a loop diameter of 2.6 mm (Cylindrical threaded PIN for dental prosthesis implantations – the US patent 1987), produced in compliance with EC regulations. The implant length varies depending on the reaching of the deep cortical region to achieve bicorticalism (14,15). A Scialom-type titanium needle with a variable diameter of 1.2-1.5 mm, certified for medical use, was used as a support structure for the ‘deep balancing’; its length varies depending on the achievement of bicorticalism. The needle is to be inserted in a direction divergent from that of the main implant while respecting the integrity of the adjoining teeth and pushed in until it reaches and impacts the deep cortical bone. Once the cortical impact depth has been reached, the Mondani intraoral welding machine is used for welding it to the implant in correspondence with the bone-mucosal emergence to form a single prosthetic abutment (16-18)

DESCRIPTION OF AESTHETIC CASES

From a wide range of case histories spanning more than fifty years, we have selected a series of six representative cases to demonstrate the clinical-functional and aesthetic validity of this immediately loaded implant-prosthetic technique.

First case

A 21-year-old patient (Caucasian race) with marked atrophy in position 11 due to homologous bone grafting prematurely. The patient has a traditional bridge between positions 12 and 21 in periodontal distress. An immediate load implant (MUM with a diameter of 2.6 mm) with a welded stabilizing needle is performed in the atrophic bone. The patient was rehabilitated with three single porcelain gold crowns and was followed for 21 years (2000-2021) (Figs. 1, 2).

Second case

A 67-year-old patient with a total upper prosthesis, 14 flap-less implants are inserted in a single session, all bicortical, as seen from the panoramic X-ray taken at the end of the operation. Immediate retention is carried out using the intraoral welding machine and a titanium bar supporter correctly positioned on the palatal mucosa. We created the final gold-ceramic prosthesis after successful osseointegration at 3 months (2000) (Fig. 3, 4).

Third case

The case refers to a 16-year-old Caucasian girl with agenesis of lateral incisors (1.2-2.2) and bilateral Angle Class I molar with a considerable decrease in the transverse diameter of the central group. The photographs show the recovery of the space obtained after orthodontic therapy (1988). The correction of the edentulism characterized not only by the limited space available but also by marked bone atrophy was carried out with the method described above and prosthetically finalized with noble metal and ceramic crowns and revised ‘only’ in November 2017 (fig. 5, 6).

Fourth case

A 58-year-old Caucasian female patient with severe discomfort in her upper incisors, mobile (grade III), and frequently abscessed. The objective examination shows the rotation of the left central incisor, composite fillings more akin to an attempt at splinting, presence of tartar and oedematous gums with reddened margins. The periodontal probe penetrates to its full length causing a fair amount of bleeding. The x-ray examination shows a bone loss around the four incisors’ roots that go beyond ¾ of the roots themselves. The four incisors are irrecoverable and must be extracted. It is possible to formulate a treatment plan that involves the extraction of the four incisors, the post-extraction placement of four bicortical and electro-welded Italian one-piece implants, and the cementation of a provisional acrylic resin prosthesis for the immediate loading of the implants in a single session (Figs. 7, 8).

Fifth case

The case refers to a 13-year-old Caucasian boy with agenesis of lateral incisors (2.2 and 1.2), bilateral Angle Class I molar, suffering from a deep bite with a considerable decrease in the transverse diameters of the central group. The photographs show the space recovery achieved with the invisible orthodontic therapy, which lasted from May 2011 to April 2014 for a total of 90 aligners.
The correction of the edentulous toothlessness, which was characterized not only by a lack of space but also by marked bone atrophy, was carried out using the method described above and prosthetically completed with noble metal and ceramic crowns (Figs 9-11).

Sixth case

A 52-year-old female patient (Caucasian) with crowding and paradentosis of the teeth of the central group. The photographs show the space recovery achieved with the invisible orthodontic therapy, which lasted from May 2011 to April 2014 for a total of 90 aligners. The correction of the edentulous toothlessness was characterized not only by a lack of space but also by marked four lower incisors with grade III mobility. After the extractions and with the help of a customized template with an aesthetic purpose, four Italian one-piece implants (2012) are placed (Figs 12, 13).

DISCUSSION AND CONCLUSIONS

Immediate loading with Italian one-piece implants is an extremely reliable, predictable technique, although it requires careful surgical preparation. Thanks to the possibilities offered by implant welding, to the possibility of using implants with immediate parallelization by bending their necks, to the possibility of using angled insertions that enable all designs to be performed to make surgery more effective, and finally, to the possibility of rapidly resolving the problems related to lack of primary fixation that can always affect an implant, whatever the technique used. Complications and failures can be avoided in most cases through careful and adequate diagnosis and specific planning (19, 21).