First experiments with endoral welding techniques have been performed in Italy by Dr. Pier Luigi Mondani back in 1970. He assumed that, by holding dental implants made by Scialom needles or monophasic screws could be applied with immediate loading to improve osseointegration and increase success rate (1). In the same period, titanium started its adoption as preferred prosthesis material, and studies focused on implant shapes that could improve primary stability for immediate loading applications (such as Garbaccio bicortical screws). In the following 40 years, implantology practice evolved towards adoption of submerged or biphasic implants. Multiple studies focused on clinical results monitored for different periods, mostly taking osseointegration as main parameter. In recent years, several studies focused on the availability of methods that could reduce patient discomfort, and, consequently, load the implants as soon as possible. Such analysis shown that intra-oral welding methods and other prosthesic techniques can be applied successfully with immediate loading of implants.
Intraoral welding procedure validation
Please note that the procedures and related results are depending on both techniques and experience of operator, who is the only person in charge of deciding the best treatment and solution that can be applied for a specific clinical case. Some of the methods described and discussed below can be applied with underlying bone structure allows immediate loading; also implant manufacturer should confirm that the procedures can be applied. Text below is informative and it does not contain any medical advice. Current medical opinion is expressed by recent publications that in the following document could not have been treated extensively nor we can assure that they are up to date with latest publications. Should you have any suggestion, correction or question, feel free to contact us.
The starting point is the assertion that osseointegration that can be obtained with submerged implants is comparable with non-submerged implants when protected from occlusion and tongue influence (2, 3). Studies focused on short and medium term results of stabilization methods when applied with immediate loading of implants, mostly with edentulous patients or where the bone cannot support the implant properly (4The following list shows some of the relevant studies published from 2000 since now:
- Intraoral procedures revision about available literature, published in 2015 pointed out that, even if long term studies are limited (when assessment is made for periods longer than 5 years), immediate loading implant success is high and single phase implants show better reliability and lower number of complications (5, 6). Conclusion shows that, with available data, short and medium term results are positive and endoral welding seems to be effective when fast mouth rehabilitation is required (7).
- Published in 2013, a study performed on 211 full arch prosthetic implants installed in a single surgical session, and stabilized with endoral welding, analyses marginal bone losses and concluded optimistically about the reliability of this method when applied for fixed and immediately loaded prosthesis (8).
- A study on 1301 non-submerged implants, published on 2001 compared immediate loading loaded implants compared with submerged implants (only the implants with acceptable primary retention were loaded immediately). Immediately loaded implants shown better success rate than those stabilized with temporary crowns or plastic prosthesis (with or without metallic frame) (9).
There are multiple documented cases of implants made with intra-oral welding techinques, whose analisys concludes that secondary stabilization limits micro-movements and improves success rates (10).
Titanium wires or flat bars can stabilize emerging part of implants during osteointegration period, mainly in the 3 months following the operation. In some of the cases it is possible to remove the welded wire when permanent prosthesis are applied. Intraoral welding process makes use of a low voltage high intensity electric current for a very short pulse. Machines are designed to be safe for both the patient and the operator. The following figure illustrate the working principle of the device:
A capacitor (C1) store electrostatic energy in form of electric charge that is taken from A mains voltage, transformed to ultra low voltage (<40V) and galvanically insulated from electrical network by T1 insulation transformer. Output terminals of T1 are safe to touch due to transformer construction. SW1 is controlled by an electronic circuit that handles capacitor charge levels according to device configuration. Before closing SW2 and starting the welding process, an internal circuit checks if there is an electrical path for discharge (e.g. the pliers are closed over titanium wire and implant). When output electronic switch closes, the whole C1 charge flows from the pliers through the titanium elements. When this current flows into titanium (with higher resistance in the electrical circuit) temperature to rises up immediately in the contact area between the wire and the implant, and it reaches nearly (but less than) titanium melting point. The speed of the thermal ramp is so fast that heat exchange outside the welded point is very limited. A first pulse breaks surface material lattice, and the second migrates the atoms and joins the two metallic structuress. The pressure applied by the pliers allows the to parts to be welded together with a process that is named sincrystallization. According to results and bone support stability, support can be kept or removed after implants have been fully integrated. Welding procedure can be applied to single and two phase screws, blades or needles. In addition to retaining effect, welding techniques can be applied also with damaged or moving implants.
A test made on 2013 on a limited number of patients shown that the welding quality that can be obtained with Nd:YAG laser is equal or better than what can be performed with sincrystallization and that tissue temperature increase is lower (5°C average deviation) (11). By contrast, intra oral welding with electrical apparatus makes use of lower cost devices and it is simpler. In our laboratory we verified that overheating can be reduced to a minimum if pliers are kept in place for some seconds after the pulse.
- Mondani PL, Mondani PM: The Pierluigi Mondani intraoral electric solder. Principles of development and explanation of the solder using syncrystallization – Riv Odontostomatol Implantoprotesi 1982 Jul-Aug(4), 28-32 – http://www.ncbi.nlm.nih.gov/pubmed/6130503
2. Pasqualini U: Le Patologie Occlusali – Masson 1993. 3. Dal Carlo L: Tongue’s Influence on the Integration of Endosseous Implants – Doctor OS Mag; 14(5): 479-484, 2003 4. Dal Carlo L: La saldatura degli impianti sommersi: oltre 12 anni di esperienza clinica – RIS Rivista Italiana di Stomatologia 2008;2:34-42 5. Barrachina-Diez JM, Tashkandi E, Stampf S, Att W (2013) Long-term outcome of one-piece implants 6. Tramonte SU, Dominici AD, Kurtzman, GM: Immediate loading with intraoral welding for improved implant stability during healing. Int J Oral Implant Clin Res 2: 85-91. 7. Andreescu CF: Survival Rate of Immediately Loaded Implants Restored using the Intraoral Welding Technique: A Literature Review. Dent Health Curr Res 1:2. 8. Degidi M, Nardi D, Piattelli A: A six-year follow-up of full-arch immediate restorations fabricated with an intraoral welding technique – Implant Dent. 2013 Jun;22(3):224-31. doi: 10.1097/ID.0b013e31829261ed. – http://www.ncbi.nlm.nih.gov/pubmed/23644910
9. Hruska A, Borelli P, Bordanaro AC, Marzaduri E, Hruska KL: Immediate loading implants: a clinical report of 1301 implants – J Oral Implantol. 2002;28(4):200-9 – http://www.ncbi.nlm.nih.gov/pubmed/12498468
10. Fogli V, Camerini M, Lauritano D, Carinci F: Success and High Predictability of Intraorally Welded Titanium Bar in the Immediate Loading Implants – Case Rep Dent. 2014;2014:215378. doi: 10.1155/2014/215378. Epub 2014 May 22 – http://www.ncbi.nlm.nih.gov/pubmed/24963419
11. Rossi F, Pasqualini ME, Dal Carlo L, Shulman M, Nardone M, Winkler S: Immediate Loading of Maxillary One-Piece Screw Implants Utilizing Intraoral Welding: A Case Report – J Oral Implantol. 2015 Aug;41(4):473-5. doi: 10.1563/aaid-joi-D-14-00332. Epub 2015 Feb 3 – http://www.ncbi.nlm.nih.gov/pubmed/25647017