Magnetic Mallet and Laser for a Minimally Invasive

: In the past, complex rehabilitations, such as the rehabilitation of an entire arch with a


Introduction
Over the past decade, the study and use of minimally invasive procedures in 26 medicine and dentistry have increased exponentially. In particular, minimally invasive 27 surgery allows a reduction in post-operative complications [1-3], a lower consumption of 28 analgesic and anti-inflammatory drugs [4], a shorter hospital stay, and therefore in 29 general a reduction in the time required to carry out a therapy. All this is even more 30 relevant when it is necessary to treat more fragile patients due to a past and / or present 31 systemic conditions, and who therefore may also have to take drugs that are 32 contraindicated to the therapeutic act that must be performed. The MID World Congress 33 defines minimally invasive dentistry as that discipline in which techniques are applied to 34 respect the health, function and aesthetics of the oral tissue, preventing the onset of the 35 disease or intercepting its progress with minimal tissue loss [5]. 36 On the other hand, the use of innovative technologies has increased the cost of 37 therapy. The use of advanced technologies, although it can increase the cost of the surgical 38 procedure, allows the patient to return to normal life earlier, generating benefits that make 39 the procedure more cost-effective than conventional surgical techniques [6]. Among these 40 new technologies, a great success in oral surgery was the Magnetic Mallet, the diode lasers 41 combined with solutions with high oxygen content (photodynamic therapy without dye) 42 and the erbium laser. 44 The Magnetic Mallet, is a surgical medical device equipped with different inserts, has 45 replaced many surgical instruments during the operations of extraction of the dental 46 elements, of implant surgery, of regenerative surgery, of removal of incongruous 47 prosthetic artifacts. The device exploits the electromagnetic impact, which allows to have 48 an impact force of high intensity and very short duration such as to obtain the plastic 49 deformation of the bone, but without propagating throughout the bone component, as 50 usually occurs with blows of the surgical hammer. [7][8] 51 For this reason the use of the Magnetic Mallet prevents the patient from the so-called 52 benign paroxysmal vertiginous syndrome, that is, vertiginous postoperative symptoms. 53 [9] The impact time is 50 microseconds and can generate a force of up to 300 kg. The 54 magneto-dynamic propulsion applies much more force, in a short time, than manual 55 instruments. The forces are focused on the treated area, limiting their dispersion in the 56 craniofacial mass as much as possible. This means more patient comfort and total accuracy 57 during the procedure. There is more precise control of the osteotome and the direction of 58 entry of the tip into the bone. This is very important as bone is generally made up of parts 59 with different densities and therefore the instrument tends to be deflected when moving 60 from one specific density to another. 61 The instruments operate with a longitudinal movement without risk of deviations 62 due to the different bone consistencies. The use of the handpiece is also very simple, in 63 fact it can be handled with one hand. For whatever procedure is used (from extraction to 64 split crest), [10][11][12][13][14][15] the forces are applied with great precision and in a predictable manner, 65 ensuring total control by the operator during surgery. 66 The Magnetic Mallet substantially reduces the generation of heat, so the use of 67 irrigation is not necessary. Since irrigation is not necessary, the visibility of the operator is 68 increased and he is able to control the progressive penetration of the instrument. The 69 mechanical frictions that develop over millionths of a second are not sufficient to increase 70 the temperature of the bone. The ergonomics of the handpiece allows it to be used with 71 one hand and facilitates its positioning in the area to be treated. 72

73
The laser is light and is characterized by its specific wavelength. The Laser (Light 74 Amplification by Stimulated Emission of Radiation) is an electromedical device which, 75 after the input of energy, determines the emission by specific chemical elements, of an 76 electromagnetic radiation, light, at high intensity, with monochromatic characteristics, 77 coherence, unidirectionality. [16] 78 The lasers used in dentistry are many and differ from each other mainly for the active 79 medium that feeds them (Erbium, CO2, Diodes ...). Each active medium (source) emits its 80 own wave-like radiant energy with its own wavelength. The various wavelengths have 81 different affinities with the various elements of the organism. [17][18] 82 Most medical lasers are in the field of the invisible. Below 375 nm there is the range 83 of UV rays, above 775 there are infrared rays. Both ultraviolet and infrared are invisible 84 as the human eye perceives light between 375 and 775 nm. 85 Depending on the target and wavelength, the laser will have different effects. 86 Er: YAG laser and CO2 laser are very absorbed by water and hydroxyapatite and 87 therefore by target tissues (soft and hard tissues), consequently the penetration into the 88 tissues will be very low (2 microns for the Er: YAG laser, 20 microns for CO2 laser) 89 therefore will not cause any effect in depth. On the contrary, Diodes and Nd: YAG lasers 90 penetrate very deeply so in addition to having a visible effect on the surface they can also 91 have effects that are not visible in depth. It is precisely on these effects that laser therapy 92 in periodontology and oral surgery is based.
Based on the concept that the laser transforms light energy into thermal energy, it is 94 evident that the effects of the lasers on the tissues are due to the increase in temperature 95 of the same due to the transfer of thermal energy by the laser sources. 96 Precisely because of important and localized increases in temperature, it is possible 97 to obtain, with lasers, the first and most evident effect, as it is visible: tissue ablation. 98 In fact, the volatilization of the tissues occurs when the temperature exceeds 100 99 degrees centigrade. 100 If the localized temperature increases significantly, it will be possible to have protein 101 denaturation effects with dissolution of collagen (between 50 ° C and 75 ° C). This 102 determines coagulation effects, however irreversible denaturation of the tissues. If, on the 103 other hand, it is possible to keep the localized temperature increase below 50 ° C, there 104 will be only a slight vasodilation, without irreversible changes in the tissues affected by 105 the laser effect. 106 The differences in the effects on the target surface of poorly penetrating ( In case of bacterial infection, the infectious process must be eliminated, then 118 decontaminated. If the bacterial infection has resulted in a loss of substance, the goal is to 119 regenerate the loss of substance thanks to laser biostimulation, which determines a sort of 120 "biological doping" for the patient's tissues, promoting their regeneration. 121 The photochemical effect (or photodynamic therapy) [20][21] consists in the activation 122 of a hyper-oxygenated tissue with a monochromatic beam; the interaction between 123 oxygenated tissues and the laser beam produces photochemical reactions in which the 124 energy acceptor is oxygen. Therefore the photosensitizing substance used must always 125 contain oxygen since the presence of oxygen allows the reactions of photo-activation and 126 production of singlet oxygen. Singlet oxygen is a free radical of oxygen (a free radical is a 127 highly reactive chemical species that has unpaired electrons in the outer layer); free 128 oxygen radicals are also produced in our body. 129 Neutrophils stimulated by antibodies release singlet oxygen which, through various 130 mechanisms, destroys bacterial cells (destruction of the plasma membrane, degradation 131 of the lysosomal membrane, alteration of mitochondrial functions, denaturation of DNA 132 molecules); however, if the bacteria are numerically too many or too aggressive, the body 133 is unable to limit the aggression and systemic administration of antibiotics becomes 134 necessary. 135 Research in periodontology [16] has developed protocols that on the one hand use 136 periodontal lasers with a low energy index, with the aim of not overheating the 137 periodontal tissues, on the other hand they use dyes (for example phenothiazine chloride, 138 characteristic of the Helbo system), which are able, injected into the pocket, to color the 139 bacteria present there. The laser energy, absorbed by the dye for which it was related, 140 determines the release of free radicals and singlet oxygen, able to denature the cell 141 membrane and lead to death of the bacteria, without damaging the host tissues. However, 142 the literature agrees that there is no statistically significant difference in terms of the 143 eradication of pathogenic bacteria between a conventional non-surgical protocol and a 144 conventional non-surgical protocol followed by photodynamic therapy with low-power 145 laser and dyes. 146 From in vitro and in vivo studies [22][23][24][25] it has been shown that the decontaminating 147 action is adequate only if the penetrating laser (diode) is set at values above 2 Watts 148 (energy necessary to be able to penetrate deeply, overcoming all phenomena of reflection, 149 refraction and transmission that reduce the absorption capacity of the beam in the tissues) 150 and if carried by a liquid, defined as photo-sensitizer, preferably transparent and with 151 high oxygenating power, so as not to reduce the depth of penetration of the laser beam 152 into the tissues, this substance is has been identified in hydrogen peroxide (hydrogen 153 peroxide H2O2, 10 volumes 3%, non-toxic to tissues). 154 The periodontal tissue, both soft and hard, previously hyper-oxygenated by 155 hydrogen peroxide irrigations, after waiting for at least two minutes, once stimulated by 156 the laser light, first releases essential oxygen and then, for the passage of an electron to 157 the superior orbital, singlet oxygen, a highly unstable molecule with a very short half-life 158 (in the order of 0.0045 microseconds) capable of binding the fatty acids of the bacterial 159 membrane and dissolving the latter, causing bacteriolysis. 160 As already mentioned, a crest power greater than 2W is required to be able to destroy 161 the red and orange Socransky bacterial complexes, this in order to be able to adequately 162 penetrate in depth. However, if the diode laser constantly emits such power levels, an 163 excessive thermal overheating would result which would lead, from an initial 164 vasodilation effect (45 °C) to a denaturation of the molecules up to the carbonization of 165 the tissues, transformations due to the progressive increase tissue temperature. 166 To overcome this problem, the possibility of interrupting the emission of laser pulses 167 has been introduced with a software that regulates the emission intervals (Ton) with tissue 168 cooling times (Toff). 169 In order to remain below the predetermined threshold of 45 ° C, the software must 170 work in microseconds (and therefore with high frequencies, up to 10 000Hz). This allows 171 you to work with high peak powers, up to 3.5W but without exceeding the average power 172 threshold of 0.8W. In addition, high frequencies, up to 10 000Hz, allow for the release of 173 singlet oxygen molecules within the periodontal tissues up to 10,000 times per second. 174 The scientific works of Rey and Caccianiga [26][27][28][29] have shown that hydrogen 175 peroxide is bactericidal only for Prevotella intermedia and for Actinobacillus 176 Actinomicetemcomitans, which the laser without irrigants (at 2 Watt of regulation) is 177 effective only on Actinobacillus Actinomicetemcomitans (therefore the laser is less 178 effective than hydrogen peroxide). All other bacteria in Sokransky's red and orange 179 complexes are resistant. 180 The combination of laser and hydrogen peroxide, on the other hand, has shown 181 efficacy on all periodontal pathogenic bacteria and, from the latest in vitro tests carried 182 out, also on Staphylococcus aureus resistant to antibiotics and responsible for skin 183 infections in defected patients. 184 Therefore, the protocol devised by Dr Rey in 1992, now called "Photodynamic 185 Therapy without dye", appears, in the light of the literature, to be effective for treating 186 periodontitis refractory to traditional methods. [20][21][22]28,29]  From the studies conducted using these protocols and from in vivo and in vitro tests 207 [20][21][22]24,25] it has proved useful to include laser-assisted protocols within the non-208 surgical periodontal therapy, since it is a "pain free" treatment for the patient, it allows 209 man-agement and maintenance complex defects reducing by 90% the need for surgical 210 treatment, framing the operative protocol in a minimally invasive perspective and 211 limiting the need to administer antibiotics, only to patients at risk, thus reducing the risks 212 of antibiotic-resistance phenomena. 213

214
OHLLT (Oxygen High Level Laser Therapy) Technology is a dye-free photodynamic 215 therapy that includes the association of a penetrating laser with a modified and stabilized 216 H2O2 solution with glycerol-phosphate, called Sioxyl Solution (derived from H2O2 10 217 volumes 3% therefore without cytotoxic actions) (Fig. 2)   As in the dye-free photodynamic therapy, conceived by Gérard Rey [19], the laser 222 energy activates the modified H2O2 solution, releasing free radicals and singlet oxygen 223 which have antibacterial activities on the Gram + and Gram-groups specific to 224 periodontal diseases. The laser is used with high power peaks and low average power 225 (<0.8 Watt). 226 The elimination of silver residues from H2O2 and stabilization with glycerol-227 phosphates resulted in, with the same bactericidal effect, an increase in biostimulatory 228 activity which results in faster healing of the irradiated tissues. 229 The scheme provides: The erbium laser emits a wavelength that is positioned in the mid-infrared spectrum, 244 at 2940nm. Thanks to the affinity that its wavelength has both with water and with 245 hydroxyapatite, the erbium laser can interact with both soft and hard tissues. The water 246 contained in the target tissues hit by the laser beam absorbs the thermal energy that causes 247 vaporization, causing an increase in pressure that causes micro-explosions capable of 248 removing the tissue (photoacoustic effect).
[30] 249 The erbium laser can intervene on the hard tissues of the oral cavity in a simple way 250 and with less trauma, creating both a gingival access flap and a rapid and precise bone 251 cut, characterized by more accurate margins of the bone breach than those obtained with 252 rotating instruments. Its air and water spray keep the temperature of the target tissue 253 unchanged, and the bactericidal effect of the laser light decreases the risk of infection. 254 This operating mechanism guarantees respect for the biological properties of the 255 bone, hindering the creation of necrosis and denaturation of the protein matrix. practice the expansion of a residual bone crest lacking in thickness and / or the preparation 262 of the implant sites, as well as the properties decontaminants and photo-bio-modulators 263 of photodynamic therapy without dye (OHLLT or Dye free Photodynamic Therapy) 264 [26,27,29]. 265

266
An 81-year-old patient undergoing treatment at the practice shows mobility of the 267 upper elements remaining to support a removable resin prosthesis. The patient requests 268 to rehabilitate the upper arch with a fixed type of prosthesis. The patient has a previous 269 history of hepatitis C still under treatment, degenerated into liver cancer in 2016, treated 270 and resolved in the three-year period 2017-2020. She also reports that she is an anxious 271 person, with current back and neck problems, while in the past she has suffered from 272 sinusitis. 273 Therefore, given the advanced age of the patient and the patient's general health 274 conditions it can therefore be considered a fragile subject (ASA-3). From the dental point of view, the patient has partial edentulism in the upper arch 281 (first class of Kennedy) with the permanence of the elements 11, 21, 22 and 23 and the root 282 residues of the elements 12, 13 and 14 and of partially osseointegrated implants in the area 283 15 and 16. In the lower arch there is a fixed rehabilitation on Toronto Bridge type implants. 284 Orthopantomography and CBCT show the remaining periodontally compromised dental 285 elements, root residues and implants not supported by prosthetic crowns that have lost 286 the vestibular cortex. There is also an inadequate thickness of the bone tissue in some areas 287 of the arch, thus having to design and apply regenerative techniques to insert implants to 288 support a fixed type of rehabilitation. 289 Considering the initial clinical situation, the patient's request and her general health 290 conditions, the extraction of the remaining dental elements, root residues and implants is 291 proposed in the same operation, and the subsequent use of the laser to Erbium and the 292 Magnetic Mallet for the preparation of the new implant sites and the insertion of 8 implant 293 fixtures. Within the next two days, the implants will be loaded with a screwed-in 294 temporary total prosthesis with immediate load of the Toronto Bridge type. The patient, 295 correctly informed, accepted and gave consent to the execution of the therapy. 296 2.1 Surgical procedure 297 On the day of surgery, the patient took an antibiotic prophylaxis based on 298 Amoxicillin and clavulanic acid (875 mg + 125 mg) one hour before the start. 299 Initially, complete anesthesia of the upper arch was performed on both the buccal 300 and palatal sides, using, as anesthetizing molecule, articaine with the addition of 301 adrenaline at a concentration of 1: 100,000. A full-thickness flap was initially performed 302 to clinically highlight the total residual bone volume of the superior alveolar process, root 303 residues and implants. 304 The simple extraction of the remaining dental elements was then performed. Instead, 305 for the removal of root residues and implants, the Magnetic Mallet was used with the 306 inserts for the extractions. This made it possible to avoid osteotomy and / or odontotomy 307 maneuvers in order to save precious bone tissue for the subsequent insertion of the 308 implants. Given the presence of infection and inflammatory tissue, photodynamic therapy 309 (OHLLT protocol) was practiced in the post-extraction sockets, by irrigation with Sioxyl 310 solution activated by a diode laser (parameters), to decontaminate in depth. Subsequently, for each of the eight implant sites, a series of steps were performed in 315 order to insert the implants with sufficient primary stability, in the best prosthetic position 316 to make the intervention as predictable but also as minimally invasive as possible. 317 Initially, the erbium laser (160 mj, 20 Hz, with an average power of 3.2 W) was used to 318 bleed the bone tissue and thus increase the regenerative potential. At the same time, the 319 ablative capacity of the Erbium Laser allowed the creation of an access for the osteotomy 320 inserts of the Magnetic Mallet. The implant sites, in fact, were prepared using only the 321 Magnetic Mallet with osteotomic inserts of increasing diameter, from 100 (apical diameter 322 of 1 mm) to 300 (apical diameter of 3 mm). Therefore, no bone tissue was removed, but it 323 was only compacted to increase its density and obtain greater primary stability. Before 324 inserting the implants, the implant sites were in turn decontaminated by photodynamic 325 therapy (OHLLT protocol). The eight implants were then inserted in zone 17 and 24 326 (diameter 4, length 10), zone 14 (diameter 4, length 11), zone 21 and 23 (diameter 4, length 327 13), zone 11 and 13 (diameter 3, 7, length 13) and zone 26 (diameter 4.7, length 10). Finally, 328 the healing screws were screwed to the implants and the flaps were sutured with a 4-0 329 silk thread, after placing the PRF previously taken and centrifuged both in the extraction 330 sites and to protect the flaps. For the realization of the prosthetic product, the impressions were made. Above, by 335 implant transfers, an impression was made with plaster mixed with fluid silicone, while 336 at the bottom an alginate impression was made. Before being discharged, the patient 337 underwent a photobiomodulation session using the ATP38 for 12 minutes. 338 The following day the patient returned to the office to perform a check-up, a further 339 photobiomodulation session using ATP38 and a test of the new upper prosthesis, in which 340 the passive fit of the rigid bar with the implants was checked, checked with 341 orthopantomography, the aesthetics and occlusion. The next day the provisional upper 342 prosthesis screwed with immediate loading was delivered. Finally, three weeks after the 343 surgery, the sutures were removed, verifying that healing took place correctly. The patient 344 reported that she did not have any particular post-operative problems and complications, 345 in particular that she did not take any anti-inflammatory after surgery and that she was 346 satisfied with the result obtained. For a further improvement from an aesthetic point of 347 view, the patient also decided to perform a lip filler based on hyaluronic acid one month 348 after the delivery of the prosthesis.

360
The rehabilitation of an arch through the extraction of compromised elements, bone 361 regeneration and the insertion of implants is generally a procedure that requires surgery 362 lasting several hours with a considerable level of trauma for the patient. It is therefore 363 essential to be able to take advantage of new technological tools that lead to a 364 simplification of the maneuvers performed during the surgery, making the latter faster 365 and less traumatic, reducing the risk of intra and post-operative complications. In this 366 specific case, using the magnetic mallet and the laser made it possible to face the clinical 367 case of a fragile patient in complete serenity with a reduction in risks and morbidity. 368 As for the magnetic mallet, having carried out the preparation of the implant sites by 369 using only the osteotomic inserts allowed to save bone tissue; in fact, it was only 370 compacted, to increase its density, thus not having to use preparatory drills that could 371 have created necrosis areas, and a consequent more severe post-operative procedure [31-372 34], with a higher risk of short-and long-term adverse post-operative consequences, first 373 of all peri-implantitis [35][36][37][38][39] 374 The combined use of the Erbium laser and the diode laser, on the other hand, has 375 both to decontaminate the infected areas, due to the presence of compromised elements, 376 and the implant sites in order to avoid any opportunistic infection that could have led to 377 poor osseointegration. [17][18][19][20][21][22][23][24][25][26][27][28][29][30] Furthermore, the biostimulatory capacity, of the diode 378 laser, has made it possible to obtain a biological "doping" for the tissues in order to 379 accelerate healing and reduce post-operative pain. [40-41] The Erbium laser, on the other 380 hand, together with the combination of the Magnetic mallet made it possible to create a 381 more precise bone breach than that created with rotating instruments, keeping the 382 temperature of the bone tissue low thanks to the air-water spray.

385
The use of tools such as the Magnetic Mallet and the Laser resulted in the 386 implementation of a therapy, normally considered traumatic, in a minimally invasive 387 manner. The patient had no pain or other complications during the surgery. She did not 388 suffer from any episodes of agitation although she herself stated that she had had it in the 389 past after previous dental surgery. The following days she confirmed that she had not 390 developed any edematous areas and that she had not had post-operative pain. She stated 391 that she therefore did not need to take pain relieving or anti-inflammatory drugs. In 392 addition, it can be said that she did not have any infectious complications. 393 It can therefore be concluded that the combined use of the laser and the Magnetic 394 Mallet has made it possible to perform complex therapies even in this patient who is 395 admittedly fragile due to clinical history and the present systemic condition. To the 396 detriment of the past, in which these therapeutic paths were reserved for a narrow circle 397 of people, this could allow in the future to be able to guarantee optimal functional and 398 aesthetic results for many fragile patients.