9
Optimizing Immediate Loading with Immediate Implants
Adriano Piattelli, Luca Comuzzi, Alessandro Cipollina, Tea Romasco, Giulia Marchioli, Natalia Di Pietro, and Amirhossein Majidi
Introduction
The long‐term success of an implant‐supported restoration is based on successful osseointegration. Adequate primary stability and absence of micro‐movements at the implant‐abutment interface are two main factors in achieving this outcome [1], together with appropriate onset of loading (i.e. traditional delayed, early or immediate). The purpose of this chapter is to define and elaborate on what is meant by “immediate loading.” Ledermann [2] first described immediate loading of threaded dental implants to stabilize mandibular over‐dentures. Thereafter, in 1990, Schnitman and colleagues [3] reported that it was possible to load threaded dental implants that supported fixed prostheses in partially edentulous individuals. We have been studying the concept of immediate loading with dental implants for over 15 years, both clinically and histologically.
History of Immediately Loaded Implants
The initial concept in implant dentistry as presented by Branemark was that for threaded endosseous dental implant devices to become osseointegrated by intimate bone‐to‐implant contact, initial healing required submerging the implant “fixture” subgingivally and leaving it buried and unloaded for at least 3 months in mandible or 6 months in maxilla [4, 5]. Any micromotions or unintentional early loading were found to result in the formation of fibrous connective tissue rather than bone at the implant surface and obvious failure to integrate [6]. However, immediate loading had been previously reported with endosseous blade‐vent implants [7, 8]. Aware of this finding, Schnitman et al. [9] serendipitously discovered that Branemark implants could be loaded immediately with a fixed full arch provisional prosthesis in fully edentulous mandibles provided that they were splinted together. In their study, 63 × 3.75‐mm diameter implants of varying lengths were placed in healed edentulous mandibles of 10 patients. Of these 63, 35 were submerged and left unloaded for the usual 3‐month healing interval, while the other 28 were immediately loaded with splinted cross‐arch provisional prostheses. After 3 months, the submerged implants were exposed and used to support definitive splinted restorations. Surprisingly, only 4 of the 28 implants that had been loaded immediately lost their integration. Meanwhile, all the 35 initially submerged implants were integrated and remained so after 10 years in function. A life‐table analysis at 10 years for the original 63 implants demonstrated a combined 10‐year survival rate of 93.4%, comprising 84.7% for immediately loaded and 100% for originally submerged implants [9]. While the differences were significant, the outcome was encouraging regarding the possibility of immediate loading following further investigation.
Subsequent studies in our histology laboratories using human specimens of threaded implants retrieved from those placed in healed edentulous sites loaded either in the traditional delayed mode or immediately showed high percentages of bone‐to‐implant contact (BIC) in both groups likely due to the fact that all implants used had been splinted together [10–12]. Immediately loaded implants also showed higher BIC than submerged, non‐loaded implants in the same patients [13]. However, a subsequent retrospective review and evaluation of 55 papers highlighted that conventional delayed loading of implants yielded higher BIC values, particularly in mandible and in anterior regions [14]. Notably, the authors reported a 25% higher BIC in mandible compared with maxilla and a 10% higher BIC in anterior compared with posterior mandible. The study also indicated a correlation between BIC and local bone density, with type 2 bone predominating in mandible and type 3 in maxilla. Of interest here, however, were our histological findings suggesting that successful osseointegration is achievable with slightly more than 30% BIC.
Some investigators have reported that long‐term clinical and radiographic outcomes of immediately loaded implants can be comparable to those employing standard submerged protocol and delayed loading (conventional loading) [15–17]. One systematic review and meta‐analysis of randomized clinical trials compared outcomes with immediate, early, or conventional loading in patients who received fixed implant‐supported prostheses [18]. Immediate and early loading performed similarly, but implant survival rates with immediate loading were significantly lower than with conventional loading. The reasons for this difference in outcomes was not clear, but certainly supported the notion that immediate loading, while challenging, is possible.
One crucial determinant for success with immediately loaded implants is their primary stability as measured with a torque wrench at implant insertion or with resonance frequency devices. Stability is affected by implant geometry, length, thread design, and surface characteristics, as well as by local bone density. It also has been shown to be significantly greater when “osseodensification” is used for osteotomy site development rather than standard implant burs [19]. High primary stability reduces strains on bone during initial healing of implants, thereby allowing deposition of osteoid matrix rather than fibrous encapsulation. Both micro‐retention via moderate surface roughness and macro‐retention via implant thread design help to diminish the risk of unwanted micro‐movements during site healing [1, 5]. The use of internal conical connection implants [20] and platform switching [21] also are of benefit. An insertion torque of 30–35 Ncm is considered acceptable for immediate loading of single implants. In immediate loading with splinted implants, insertion torques can be lower than with single implants [22], since joining several implants together again reduces micro‐motion [23].
Immediate loading stands out among innovative procedures marking significant steps forward in implant dentistry. Indications for it, well documented over the years, range from implant placement in the fully edentulous healed mandible and maxilla to single tooth applications in extraction sockets. Thus, current accumulated evidence supports the fact that even implants placed immediately at the time of tooth extraction can in many situations be loaded immediately [24–28]. A consensus statement in 2014 defined implant placement at the time of tooth extraction combined with immediate restoration/loading the same day or up to 1 week post‐implantation as type 1A [22]. This treatment approach, however, is highly demanding especially in achieving acceptable esthetic and psychological outcomes for the patient. Done properly, immediate restoration of IIPs in the esthetic zone also has the potential to improve soft tissue healing and contouring [25, 29, 30] as well slightly reducing early crestal bone loss compared with IIP using delayed provisionalization.
In modern implant dentistry, while well‐controlled, immediate loading may and indeed in future should become routine treatment, success will depend on a full understanding of the biological and technical essentials as outlined by experts in the field. Knowing when not to load immediately also is fundamental as treatment failure will have significant implications for both clinician and patient. From a prosthetic point of view, criteria such as type of occlusion, patient diet and parafunctional habits, patient compliance and expected level of oral hygiene are key considerations.
Two types of immediate loading have been described in the literature. One is immediate functional loading (IFL) or immediate occlusal loading meaning that the provisional restoration will settle in light habitual occlusal contact in centric occlusion only but without contact in lateral or protrusive movements. The second type is termed immediate nonfunctional loading (INFL) or immediate non‐occlusal loading, often accomplished using only healing abutments. If a transitional restoration rather than a healing abutment is used for single IIPs, it will be modified to avoid any contact with the opposing arch. However, as with a healing abutment, it will still be exposed to some indirect loading and thereby benefit from stimulation of osteogenesis with minimal crestal bone loss due to remodeling during healing compared to delayed loading [13].
Microstructure of Bone under Loading
Wolff’s time‐honored experimental work determined a direct correlation between mechanical loading and bone formation, proposing that carefully controlled stresses applied to bone will serve to stimulate its formation, while decreased levels of stress can lead to resorption (i.e. disuse atrophy) [31]. Bone microstructure including density and mineral content will adapt according to the mechanical stresses received. Properly loaded implants exhibit higher density of peri‐implant bone and BIC compared with non‐loaded implants, and those subjected to immediate loading demonstrate a 34% increase in bone density and mineral content with greater BIC compared with non‐loaded implants [32–35]. In a rodent model, Yorioka et al. [36] reported statistically significant differences (p < 0.05) in bone characteristics (volume, trabecular number, trabecular thickness, and bone mineral density) at 21 days postoperatively between IFL and INFL, with IFL being superior.
Immediate Loading of Immediate Implants
As stated, most available information on immediate occlusal loading (IFL) relates to implants placed at healed extraction sites and restored using splinted prostheses. Much less information exists on immediate loading of IIPs. In addition to the obvious advantage of shorter overall treatment times and fewer surgical procedures, as reviewed in other chapters of this book, the IIP approach helps to minimize the typical alveolar ridge remodeling and shrinkage following routine extractions. The IIP approach also allows for optimal three‐dimensional implant positioning and preservation of peri‐implant soft tissue architecture including preservation of papillae.
Disadvantages with IIPs include challenges in achieving good primary stability due to the discrepancies between implant diameters and post‐extraction socket dimensions, the need for increased precision and skills of the surgeon, increased risks of infection and failures, and the need for knowledge and experience in hard and soft tissue grafting procedures [37–39]. While it has been suggested that greater implant stability can be achieved in healed sites [40], as already discussed, histological studies in our laboratories have shown that immediate post‐extraction implants definitely can undergo osseointegration despite lower initial stability. Indeed, one of our human histologic studies showed no differences in BIC with IIPs compared to implants inserted at healed sites [41]. Furthermore, one case report including histology detected no differences between two IIPs in the same patient, one being occlusally (IFL) and the other being non‐occlusally loaded (INFL) using only a healing abutment [42].
There is no doubt that immediate loading, whether IFL or INFL, requires considerable clinical experience in order to be successful. At the Center for Advanced Studies and Technology, University of Chieti‐Pescara, Italy, we have long been attempting to define criteria for succeeding routinely with immediate loading of IIPs. A novel approach that we have been using for some time now includes:
- Implementation of “Biconometry” (i.e. utilizing both a Morse cone internal connection between implant and abutment along with a conometric connection between abutment and prosthetic crown to eliminate the need for cement or screw retention and facilitate retrieval of prostheses if need be).
- Use of dynamic navigation to enhance precision in implant site development.
- Pre‐ and immediate postoperative use of a zinc‐L‐carnosine mouthwash.
- Application by patients of complex magnetic fields (CMFs) to accelerate healing of peri‐implant hard and soft tissues.
Biconometric Concept and Navigated Surgery
Traditional modes of retaining fixed prostheses to dental implants have included screw retention, cementation or more recently a combination of the two (i.e. cementing the crown beforehand and then retaining this abutment/crown single unit with a screw). All can be successful if established protocols are followed. At present, most major dental implant manufacturers offer internal conical connections for prosthetic insertion, which can help to achieve zero long‐term bone loss [43]. The etiopathogenesis of peri‐implant crestal bone resorption has been extensively investigated [44]. One significant contributor may be bacterial colonization of the implant–abutment interface, and this has been linked to the type of implant–abutment connection [45]. Both in vitro and clinical research spanning the two decades 2000–2020 demonstrated that internal conical connections such as Morse cone connections (MCCs) markedly diminish this bacterial infiltration [46–48]. They also substantially reduce unfavorable micro‐movements at the abutment‐implant interface; combined, these two features have been shown to help in reducing crestal bone resorption. They also favor improved peri‐implant soft tissue health due to reduced local inflammation that could lead to mucositis and negatively impact the long‐term success of implants [49–51]. Work from our laboratories [52, 53] has underscored this biologic superiority of MCCs to others such as internal hex connections. In addition, the MCC allows the surgeon to apply an inter‐implant distance slightly less than 3 mm without risking proximal bone loss, thereby helping preserve inter‐implant bone peaks over time. Reduced micro‐movements also help to prevent prosthetic retention screw loosening. Moreover, subcrestal implant placement becomes feasible, and this again helps to minimize crestal bone loss [54–56].
Internal conical or biconometric concepts now have also been introduced for connecting implant abutments to prosthetic copings rather than using screws or cement. This can reduce risk of prosthetic misfits leading to risks of implant fracture or peri‐implantitis. The combination of biconometry and an MCC implant connection can theoretically create more or less optimal conditions for minimizing crestal bone loss [53, 57]. It also offers easier insertion and removal of prosthetic components [46, 53, 58] due to precise coupling (i.e. friction between abutment wall and prosthetic cap which incorporates a 4‐ to 6‐degree angle.)
Biconometry is applicable with single, multiple, and full‐arch rehabilitations, including those supported by IIPs with absence of screw holes in prostheses and easy retrieval in the event of implant complications. However, full‐arch rehabilitations may require elevation of mucoperiosteal flaps to expose alveolar or basal bone for recontouring or so‐called “tabling” (Figure 9.1). Implants should be positioned with equal heights and adequate spacing to allow effective inter‐implant oral hygiene post‐restoration. They should be subcrestal (1–3 mm) and connected to abutments of 1.5, 3, and/or 4.5 mm heights ensuring that repositioned soft tissues do not cover the conometric coupling area. Patients are then provided with temporary polyether‐ether‐ketone caps to protect the abutments, and if need be modification of any prosthesis as an overnight temporary. The following day, a laboratory‐fabricated definitive prosthesis (Toronto Bridge [59]) with conometric copings is delivered.
Figure 9.1 (a) The mandibular teeth were extracted and site preparation performed in readiness for immediate implant placements using dynamic navigation. (b) Conometric straight and parallel abutments of the same overall height were connected to the implants. (c) Temporary polyether‐ether‐ketone caps were added to safeguard abutments overnight and a provisional prosthesis or a three‐dimensional printed tray (Effegi Brega Srl, 29010 Sarmato, Italy) inserted. (d) The following day, the definitive prosthesis (Toronto bridge) was placed filling gaps in the prosthesis base with composite resin. The occlusive fit is verified, and the prosthesis polymerized for a few minutes. (e) Clinical view of the definitive prosthesis. (f) Postoperative panoramic radiograph.
A case of an immediate maxillary central incisor implant with IFL is shown in Figure 9.2. Following flapless extraction, the IIP was inserted towards the palatal socket wall to leave a large buccal gap (Figure 9.2a). This gap was then packed with a porcine bone xenograft biomaterial (GTO®; OsteoBiol® by Tecnoss®, Giaveno, Torino, Italy; Figure 9.2b). A radiograph taken at this point is depicted in Figure 9.2c. Note the depth of implant placement and inserted conometric abutment. Because of very good initial stability, the definitive restoration was inserted 24 hours later and is shown here after 1 month in function (Figure 9.2d), helping to retain the original soft tissue contours and papillae at 3 months after disconnecting the crown. (Figure 9.2e). At 1 year post‐implantation, the soft tissue contour and papillae had stabilized nicely (Figure 9.2f) and a radiograph verified stable peri‐implant crestal bone (Figure 9.2g).
Figure 9.2 Intraoral images of a post‐extraction immediate functionally loaded implant placement in the esthetic zone featuring a biconometric connection. (a) Placement the immediate implant. (b) After connecting the conometric abutment and grafting the buccal gap with porcine collagenated biomaterial. (c) The immediate postoperative radiograph. (d) Clinical outcome with the definitive restoration at the 1‐month follow‐up. (e) Soft tissue healing after 3 months in function. (f) The clinical outcome at 1 year. (g) The radiographic status at 1 year.
Figure 9.3 (a) A preoperative radiograph showing the hopeless maxillary left central incisor and an existing implant without conometric connections in the position of the right central. (b) The preoperative cone beam computed tomograph. (c) After flapless extraction, an immediate implant was placed considerably subcrestal. (d) A conometric straight abutment was attached before grafting the buccal gap. (e) A radiograph of the immediate implant placement (IIP) with the previous crown adapted as the immediate functionally loaded (IFL) temporary. (f) The peri‐implant soft tissues after 2 months of IFL. (g) Ten days after delivery of the definitive restoration; note the superior outcome compared with the previous implant placed more or less epicrestal and without a conometric abutment. (h) The clinical and (i) radiographic images at the 1‐year follow‐up; note the stability of the IFL IIP site.
Another IIP case in the esthetic zone is shown in Figure 9.3. The patient presented with an existing single implant replacing the right central incisor and a failed, left central incisor tooth (Figure 9.3a,b). The existing implant had been restored with standard, nonconometric technique, and had already suffered some crestal bone loss. The failed tooth was removed without raising a flap and an IIP placed towards the palatal socket wall and subcrestal (Figure 9.3c, d). After connecting a conometric abutment, the original tooth crown which had been kept by the patient was modified as the IFL‐loaded immediate temporary (Figure 9.3e). After 2 months of site healing, the soft tissue contours had been well maintained (Figure 9.3f), and the implant was ready for definitive restoration. Figure 9.3g shows the clinical status 10 days following final restoration (note the superior esthetics compared to that of the previously placed and restored implant), while the last two images (Figure 9.3h,i) show the clinical and radiographic situation 1 year following treatment completion.
A third case is that of a patient with two failed maxillary central incisors (Figure 9.4a). Treatment was undertaken as with the previous single implant cases but with two IIPs (Figure 9.4b) and IFL using the original crowns (Figure 9.4c). After 3 months with the temporaries, the bone levels remained stable (Figure 9.4d). Figure 9.4e shows the clinical status 6 months following the definitive restoration while Figure 9.4f shows the radiographic appearance at 1 year post‐treatment.
Figure 9.4 (a) The preoperative radiograph of a patient with two hopeless maxillary central incisors. (b) Placement of the two implants with biconometric connections. (c) After gap grafting immediate provisional immediate functional loading was achieved using the previous crowns splinted for temporization. (d) Radiographic control after 3 months; note the previously placed lateral incisor implant managed with standard non‐conometric technique. (e) Clinical outcomes 6 months following final restoration. (f) Radiographic evaluation at 1‐year post‐treatment follow‐up.
Figures 9.5 and 9.6 depict IFL‐loaded IIPs placed for a maxillary first bicuspid and canine respectfully.
Figure 9.5 (a) A maxillary left first bicuspid required replacement. (b) Flapless technique was used for the extraction and placement of an immediate implant subcrestal. (c) A radiograph taken after grafting the gaps with porcine xenograft and placing the conomeric abutment. (d) A postoperative image of the implant immediate functional loading with the modified original crown. (e) The condition of the peri‐implant soft tissues after 2 months. (f) The radiographic and (g) clinical outcome at 6 months post treatment.
Figure 9.6 (a) This patient’s maxillary left canine had failed adjacent to an existing implant restored using a tradional abutment. (b) An immediate implant was placed and connected with a biconometric connection followed by gap grafting. (c) The corresponding postoperative radiograph. (d) A postoperative cone beam computed tomograph confirming intact buccal and palatal cortical plates. (e) The previous crown was relined and inserted with immediate functional loading. (f) Soft tissue healing at 2 months. (g) The clinical status post definitive restoration. (h) The radiographic evaluation 4 months, and (i) 3 years later.
The final case is one where the final restoration was restored with a cemented, screw‐retained restoration (Figure 9.7a, b). The retained root was extracted and an IIP placed with a healing cap only (Figure 9.7c), but 48 hours later a custom transitional crown was inserted and adjusted for very light occlusal in centric and no off‐axis loading (IFL; Figure 9.7d,e). After 3 months site healing and removal of the temporary crown, the soft tissue profile was seen to be well maintained (Figure 9.7f,g).
The laboratory fabricated definitive restoration, a cemented, screw‐retained crown which was prepared for insertion and a clinical view of the final crown 1 year in function are shown in Figure 9.7h–j.
Success with IFL‐loaded IIPs requires meticulous execution of the surgical phase and dynamic computer‐aided technique (dCAIS) is particularly valuable in this regard [60].
Use of Dynamic Navigation for Immediate Functionally‐Loaded Immediate Implant Placement
Dynamic guided implant surgery (dCAIS) or navigation uses advanced technology to facilitate precise implant placement based on cone‐beam computed tomographic (CBCT) planning (Figure 9.8). It uses two cameras, a computer, and the patient’s CBCT to provide virtual visualization of the surgeon’s hand and all relevant anatomy guiding the surgeon’s movements to an accuracy of a tenth of a millimeter. Surgical templates are not essential, allowing the surgeon to employ instruments based on specific bone density and thickness without interference from a template. Ultimately, implant placement is achieved with micro‐precision adhering to the predetermined virtual plan. A post‐surgical CBCT is conducted to ascertain any deviations from the initial plan facilitated by dedicated software (EvaluNav®) within the Navident EVO system (ClaroNav Inc., Toronto, ON, Canada) [61, 62]. The technique is particularly helpful in paralleling osteotomies in cases needing multiple implants, and streamlines prosthetic procedures during placement and removal of conomeric components with their 4‐ to 6‐degree parallel “friction” design between abutments and prosthetic caps eliminating need for additional cement or screws and avoiding unsightly holes in the prosthetic work.
Figure 9.7 (a) The maxillary left first bicuspid was deemed inappropriate for traditional restoration. (b) The preparatory cone beam computed tomograph revealed adequate bone for an immediate implant. (c) At the time of surgery, a healing cap only was placed for 48 hours. (d) A custom‐made transitional was laboratory prepared. (e) The custom transitional crown was installed 48 hours post‐surgery. Note the adjustment to allow only light centric occlusion and none in lateral excursions. (f) An occlusal view of the well‐maintained buccopalatal alveolar ridge anatomy and soft tissue profile surrounding the implant. (g) A buccal view of the situation at 3 months, showing good retention of papillary form. (h) The laboratory fabricated definitive restoration. (i) A cemented, screw‐retained crown rather than a conomeric abutment was prepared for insertion. (j) A view of the final crown. (k) Final radiograph 1 year in function.
dCAIS offers several advantages over implant placement using surgical templates (“static‐guided surgery”). Firstly, the need to ensure stability of surgical templates is eliminated. dCAIS is applicable in both simple and complex cases, including those with marked jaw atrophy. The flexibility to modify a surgical plan even moments before commencing the procedure is a significant advantage. This includes the option to choose between raising flaps and flapless surgery. The approach also reduces the risk of overheating surgical burs as delivery of saline is not encumbered by a surgical guide. Also of benefit is improved accessibility to posterior jaw sites facilitated by the use of small and ergonomically advantageous instruments rather than the longer instruments needed with static surgical guides. In addition, dynamic surgery allows more accurate perception of bone quality as it eliminates obstacles that hinder haptic perception of bone density. This simplifies the surgeon’s ability to adjust site preparation protocols to achieve the primary stability necessary for immediate implant loading [63–65]. The introduction of this technology along with artificial intelligence (AI), and robotization of workflows continues to bring significant transformations to implant surgical procedures. It can enhance precision, reduce vulnerability to human errors and emotional influences due to unexpected stress, and likely will become the prevailing standard operational protocol in the foreseeable future.
Pre‐ and Immediate Postoperative Use of a Zinc‐L‐Carnosine Mouthwash
Achieving success with IIPs requires effective management of postoperative inflammation. Chlorhexidine mouthwash, which causes considerable tooth staining and rare instances of sensitivity, is commonly used for prevention. In our collective experience, a rinse with zinc‐L‐carnosine, with its antioxidant, membrane‐stabilizing, anti‐inflammatory, and cytokine‐modulating properties [66], is a suitable and preferred alternative. Widely studied in gastroenterology for its efficacy in treating peptic ulcers and esophagitis, zinc‐L‐carnosine (ZnC) has emerged as a valuable treatment option for various inflammatory conditions, including oral mucositis and ulceration [67].
Figure 9.8 Representative images of dynamic computer‐aided implant surgery (dCAIS) used for mandibular implant positioning. (a) Implant planning for the final prosthetic rehabilitation. (b) The initial cone beam computed tomograph and implant placement plan. (c) Guided implant placement executed by the surgeon following the target view on a computer screen, enabling real‐time verification of the entry point, depth, and angulation of the planned osteotomy. (d) Use of an optical tracking tag fixed to the jaw (JawTracker®, ClaroNav Inc., Toronto, ON, Canada) during surgery to track the dental arch and ensure implant parallelism.
Zinc is essential in various enzymatic systems, including matrix metalloproteases, which play a significant role in immune system activity and various cell functions including protein and DNA synthesis and cell division [68]. Its deficiency can cause delayed wound healing. L‐carnosine is a dipeptide found primarily in muscle and is composed of β‐alanine and L‐histidine, and combined with zinc, plays a significant role in wound healing [69], including that of bone [70], by downregulating proinflammatory signals and upregulating the expression of anti‐inflammatory signals [71]. As a component of a mouthwash, ZnC adheres well to oral mucosa, explaining its effectiveness in patients suffering from mucositis and esophagitis [72]. The formulation (Hepilor®, Azienda Farmaceutica Italiana, Sant’Egidio alla Vibrata, Teramo, Italy) consists of 39.53 mg of ZnC per 10 ml of suspension, mixed in distilled water and sodium alginate, and is well‐tolerated by patients without altering taste or staining teeth. It also has been shown to be of benefit for conditions characterized by dry mouth. A sample case with its use in a case of IIP with IFL is shown in Figure 9.9. The patient’s maxillary left lateral incisor required removal (Figure 9.9a, b), and the clinician opted to use the socket shield approach [73], leaving a thin section of tooth and periodontium buccally (Figure 9.9c). An IIP was placed (Figure 9.9d) and the original crown prepared as a temporary (Figure 9.9e) and connected to the implant (Figure 9.9f). The patient was prescribed Hepilor mouthwash for use and appeared to have experienced accelerated soft tissue healing at a 6‐day follow‐up (Figure 9.9g). The condition of the soft tissues at a 70‐day follow‐up is displayed in Figure 9.9h.
Figure 9.9 (a, b) The patient’s maxillary left lateral incisor required removal. (c) The tooth was sculpted to retain a buccal socket shield. (d) An immediate implant was placed after removing the remaining tooth fragments. (e) After gap grafting, the original tooth crown was modified to be used as temporarization without immediate functional loading. (f) The insertion of the temporary the abutment. (g) The soft tissue healing after 6 days of zinc‐L‐carnosine mouthwash use. (h) The condition of the soft tissues at a 70‐day follow‐up.
Use of Complex Magnetic Fields during Healing of Immediate Functionally Loaded Immediate Implant Placements
Another contemporary technology with potential to facilitate successful outcomes with IFL‐IIPs can be the use of complex magnetic fields (CMFs); that is, magnetic and solenoidal vector fields generated by the movement of electrical particles or by electric fields that produce electromagnetic fields. Magnetic fields can occur naturally in various conditions and events in nature. The earth’s geomagnetic fields likely have been integral to the evolution of living organisms although precise mechanisms have not been fully elucidated. A prevailing hypothesis is that magnetic fields may influence molecules containing iron ions. Living organisms from microorganisms to birds have been shown to use magnetic fields in various ways including cellular functions such as oxygen transport by hemoglobin and the function of specific molecules such transferrin, ferritin and lactoferrin. Pulsed magnetic fields generated by very‐low‐intensity solenoids can influence biological tissues. For example, they can initiate physical signals in cell membranes subsequently transmitted to intracellular transduction systems resulting in promotion of cell proliferation and increased production of growth factors like transforming growth factor beta and bone morphogenic proteins [74–76]. Additionally, they can influence differentiation of mesenchymal stem cells into the osteogenic lineage, leading to the production of collagen and extracellular matrix glycoproteins with promotion of mineralization [77].
Figure 9.10 A complex magnetic field device is provided for the patient to use at home during initial site healing.
Complex magnetic fields are administered using various applicators and markedly diverge from conventional magnetic fields employed therapeutically. The magnetic fields produced are of low intensity and variable frequencies. Their applications avoid adverse tissue temperature increases and are well tolerated. They promote upregulation of anti‐inflammatory cytokines [78] as well as having antimicrobial benefits [79]. When applied after surgical procedures (Figure 9.10), CMFs provide anti‐edema and anti‐inflammatory properties releasing cytokines effective in the transformation of macrophages from M1 (inflammatory state) to M2 (anti‐inflammatory state), thereby expediting postoperative recovery [80] and accelerating tissue repair and morphogenesis.
When used in the field of implantology, CMFs can be particularly beneficial for cases with immediate loading of IIPs, especially when full thickness flaps have been raised with disturbance of periosteum. Initiating CMF application 2 weeks before a surgical procedure capitalizes on its antimicrobial properties and its capacity to restore the redox state of the tissues. Immediate postoperative usage extending over a period of 45 days is also employed for its regenerative effects. Overall, CMF devices can be described as beneficial cellular communicators that can significantly enhance bone and soft tissue healing after surgical interventions.
Conclusions
Despite early speculations that immediate dental implants could not be considered for immediate loading, ongoing research has proved otherwise. Both immediate functional and immediate non‐functional loading will reduce time needed for osseointegration by kickstarting osteogenesis.
The protocols that we have developed and now routinely use for immediate loading of IIPs will be new to most readers of this chapter, but the biological and mechanical principles in using IIPs remain the same. Minimally traumatic and flapless tooth removal, proper three‐dimensional, prosthetically driven implant positioning, and gap grafting to avoid unfavorable buccal bone resorption and soft tissue recession must always be used. Cases chosen should be highly selected avoiding individuals with poor compliance, inadequate hygiene, smoking habits, or known parafunctional activity. In the end, adequate initial stability will be crucial if either IFL or INFL are to be included in patient treatment as is meticulous care in preparing and inserting transitional restorations. In an ideal world, IIPs meant for immediate occlusal loading would always be placed using dynamic computer‐assisted technique, but this will need time to achieve more widespread acceptance by the dental profession.
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