Multiprofessional approach for class III malocclusion rehabilitation with autogenous calvarial bone graft followed by Le Fort 1 osteotomy and implant-supported prostheses – case report

Extensive treatments can eventually be challenging. Even more so when the patient has limitations such as extensive tooth loss and skeletal changes, including overgrowth of the lower jaw. When indicated, these treatments tend to discourage patients due to the history of previous failures. Therefore, in addition to an interdisciplinary dental team composed of oral and maxillofacial surgeons, and prosthodontists, a nutrologist, a speech therapist, and a psychotherapist were involved in the treatment of this case. A 52-year-old female patient, Angle Class III malocclusion, with few teeth and extensive maxillary bone loss, attended the dental clinic of the Brazilian Association of Dentistry in Uberlândia. The treatment involved reverse planning, extraction of the dental remnants, calvarial bone grafting, placement of 6 titanium implants (Neodent) in the maxilla (upper jaw) and 5 in the mandible (lower jaw), orthognathic surgery, and installation of implant-supported fixed complete dentures in both jaws. Furthermore, psychotherapeutic and nutrologist’s interventions were necessary during the dental treatment, concluding the treatment with speech therapy. Within the limitations of this case, the multidisciplinary approach proved to be efficient. It promoted the reestablishment of the stomatognathic system functions without compromising nutrition during the periods when it was impossible to wear prostheses for better healing of the tissues.


Introduction
Edentulism is a frequent problem in some places, depending on the culture and socioeconomic conditions. Populations affected by this condition present changes in masticatory performance, which negatively impact the quality of life, self-esteem, and nutritional status. Partial or complete edentulism may be associated with congenital and acquired bone and soft-tissue malformations, parafunctional habits, as well as intrinsic and extrinsic factors. (de Avila et al., 2013;Frejman et al., 2013;Gondivkar et al., 2019;Khan et al., 2018). Abnormal changes in the craniomaxillofacial development could generate discrepancies in the positioning of facial bones, culminating in an unsatisfactory occlusion. Changes in the bone bases of the maxilla and mandible in relation to the skull base are major factors for the diagnosis of dentofacial deformities. The absence of a satisfactory occlusion is a worrying factor manifested through signs and symptoms such as tooth loss, limitations of jaw excursion movements, relevant changes in the soft and bony structures of the supportive periodontal tissues, along with changes in the temporomandibular joints and subsequent dysfunctions in its internal structure. Furthermore, the absence of teeth leads to an unsatisfactory overloaded occlusion which must be considered (Bitiniene et al., 2018;Brandini et al., 2016;Saber et al., 2018). Angle Class III malocclusion is a skeletal deformity presented through a characteristic excessive increase in the volume and mandibular length characterizing anteroposterior deficiency of the maxilla. Class III patients have the bone bases of their jaws badly positioned in relation to the skull base uni or bimaxillary. Orthognathic surgery can be performed to correct these deformities. In the absence of teeth, implants are a good alternative to reestablish the bases for prosthetic rehabilitation (Branemark et al., 1977), although in some situations, the patient has so many limitations that this type of treatment becomes challenging due to the comorbidities.
The placement of implants requires sufficient bone in the alveolar ridge to enable fixation and osseointegration, in addition to well-controlled systemic health conditions, allowing oral rehabilitation procedures. Patients who have lost teeth at a young age may suffer from bone resorption of varying morphologies in the different edentulous areas compared to areas where the tooth presence preserved the alveolar bone due to the masticatory stimulus (Cawood & Howell, 1988;Khan et al., 2018;Kurahashi et al., 2015). In areas lacking enough bone, grafts are a great alternative to gain bone structures, such as atrophic jaws reconstructions (Benech et al., 2011;De Santis et al., 2012;Pieri et al., 2012;Ribeiro-Junior et al., 2009;Soehardi et al., 2015;Varol et al., 2016). Autogenous grafts are often used for this purpose. The most relevant donor sites for the oral region are the mandible ramus, more precisely, external oblique line, as well as mental protuberance, iliac crest, and skullcap, all of them presenting high success rates and stability (Aloy-Prosper et al., 2015). Implant installation and grafting can be performed in the same surgical procedure when the case favors minimal implant stability. However, some cases require a waiting period for the biological osseointegration to occur, ensuring greater safety on the procedure and higher success rates in implant osseointegration (Chiapasco et al., 2007;Ferri et al., 2008;Rasmusson et al., 2012).
In the following case report, we present a clinical case of facial skeletal deformities in which the rehabilitation was possible performing a calvarial bone grafting in association with implant installation, followed by orthognathic surgery and implant-supported fixed complete dental protheses.

Informed Consent Form
The oral treatment was performed at the integrated clinic of the Brazilian Association of Dentistry in Uberlândia, Minas Gerais, Brazil. It is a recognized dental education institution where all treatments require an Informed Consent Form signed by the patient who acknowledges that their case may be used for educational purposes. Approval from the ethics committee is not required for this case report.

Case report
A 52-year-old female patient, classified as ASA I according to the American Society of Anesthesiology, attended the integrated clinic of the Brazilian Association of Dentistry in Uberlândia complaining of masticatory impairment and unsatisfactory aesthetics. The patient reported unsatisfying experiences with previous alternative treatments, expressing discouragement regarding the possible future treatments due to previous failures. During clinical examination, the patient presented a class III skeletal deformity (mandibular prognathism), hypermentonism, and dental midline deviation as well as Research, Society and Development, v. 10, n. 7, e7710716276, 2021 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v10i7.16276 4 mandibular asymmetry due to uneven vertical excess growth. There were also few teeth remaining due to previous treatments and a poor prognosis in conventional oral rehabilitation. The complementary imaging exams requested were computed tomography, panoramic radiograph ( Figure 1 A-C) with disocclusion of the teeth to evaluate the possibility of utilization and permanence of the present teeth. Therefore, the authors excluded the possibility of orthodontic treatment due to the cost-benefit aspect of this specific case and the poor prognosis of the remaining teeth. An alternative treatment was then proposed for oral rehabilitation using a bone graft along with correction of skeletal deformities by orthognathic surgery. In the first moment, upper and lower jaw teeth were extracted, followed by the installation of two provisional prostheses establishing an Angle's class I occlusion. After 3 months of bone healing without intervention, a new radiographic examination was performed to check bone levels and bone deficient sites to plan the grafting procedure.
The treatment proposed was a maxillary reconstruction using autogenous unilateral calvarial bone graft; placement of six implants in the maxilla and five in the mandible; orthognathic surgery combining Le Fort 1 osteotomy and symmetrical linear maxillary advancement; and an immediate fixed complete provisional prostheses by fixing the previous removable prostheses onto the implants using acrylic resin. For this case, an autogenous graft was chosen, blocks were removed from the parietal bone in a hospital with local anesthesia. The bone graft was removed by the neurosurgery team, more precisely, the outer cortex of the diploe at the right-side parietal eminence between the lambdoid suture and the sagittal suture, where the bone is thicker. The technique was performed as previously described (Sbordone et al., 2009). Onlay and inlay bone grafts were performed in the maxillary alveolar ridge and sinus floor sites, anchoring and stabilizing the bone blocks with steel wire (Acyflex #1). Research, Society and Development, v. 10, n. 7, e7710716276, 2021 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v10i7.16276

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The patient was advised not to wear the prostheses for 5 months to improve the graft healing. A new pair of provisional prostheses was made and relined with soft material. Also, the prostheses were used for reverse planning as a surgical guide. New imaging exams (computed tomography) ( Figure 2) were performed afterward, showing an increase the alveolar ridge bone level and a better condition of the maxillary arch to receive implants.  Source: Author's creation.
These bars are also important to enable the best virtual planning for orthognathic surgery by the radiopacity of the metal, delimiting the plane of the arches on imaging exams. The provisional prostheses were intended to be installed in a position that would be ideal for adapting to the post-operative disposition of the tissues, regardless of the occlusion at this moment. At the installation, the ratio of prostheses in the arch characterized a class III with anterior open bite. Due to the feeding restrictions, the patient was referred to nutritional monitoring. New measurements using virtual orthognathic planning software were made.
The patient underwent general anesthesia. Local anesthesia with a vasoconstrictor was injected in the operating site.
The glabellar external reference pin was inserted. Le Fort I maxillary osteotomy was performed causing a total rupture of the maxillary pillar areas by a controlled down fracture and Howe's forceps pressure lever. The prostheses installed at the moment of the surgery guided the previously planned maxillary position. The arches were stabilized employing intermaxillary fixation throughout the prostheses ( Figure 4A and 4B). Source: Author's creation.
The sinus gap was filled with exogenous grafts (Bioss Gaishlesh) and was anchored and stabilized with a set of titanium plates and screws (Signo Vinces) ( Figure 4A and 4B). A reduction in the proportion of the chin was anchored by rigid internal fixation and was carried out using mini plates and titanium screws of the 2.0 system (Signo Vinces), thus promoting the correct positioning of the maxilla in relation to the skull base with correction of the mandibular asymmetry creating a better maxillomandibular relationship with an adequate vertical and horizontal proportion of the face. A trans-surgical radiograph was performed to check the maxillomandibular relationship and position. The patient remained with the intermaxillary fixation only during the surgery until the fixation of the bone stumps and stabilization of the maxillomandibular connection, being removed immediately after the end of the surgical procedure. The prostheses were removed 3 days after surgery so that there was no loading or displacement of the anchorages. The patient did not wear the prostheses for 3 months to ensure proper healing of the tissues and avoid overload of the graft. Drug therapy consisted of antibiotics and analgesics according to the prescription recommendations. Immediate post-operative diet was exclusively liquid, and pasty as indicated by a nutritionist.
Oral mucosa hygiene consisted of 0.12% chlorhexidine mouthwash rinse for 7 days.
After the 3-month period, the patient was able to receive the permanent implant-supported fixed complete prostheses.

Discussion
A multidisciplinary and interdisciplinary approach was necessary in this case. The dental team performed the surgical and prosthetic procedures. A nutrologist was consulted for food supplementation and a speech therapist conclude the treatment adapting the patient to the new prostheses and correct functioning of the stomatognathic system. Psychological monitoring was fundamental to access the patient's well-being due to functional and aesthetic changes.
The use of implants to rehabilitate this patient was a good alternative as they act as bases for implant-supported fixed complete dental prostheses, reestablishing the stomatognathic system functions, which directly influences the masticatory performance as well as the patient's general health and self-esteem as seen in other studies (Bitiniene et al., 2018;Branemark et al., 1977;Gondivkar et al., 2019;Khan et al., 2018).
During the orthognathic surgical planning, the dental arches were not in a favorable relationship. The patient fractured the provisional prostheses and was instructed not to wear them due to the lack of occlusion and discomfort caused by fractured areas. The patient was instructed to seek care from a nutrologist to adapt the diet to her current limitations, knowing that chewing influences nutrition and general health (Bitiniene et al., 2018;Gondivkar et al., 2019).
Cases like the one presented are not common, but it is important to understand and discuss the solution of choice to rehabilitate patients affected by both malocclusion and the loss of many teeth. All cases must be considered individually and have the appropriate planning for each situation, the best treatment option, as discussed by the team in charge of this case, was described in this report.
The case took 3 years from start to finish, which could be considered a significant amount of time compared to similar cases, in which there is the possibility of minimal anchoring of the implants associated with graft and orthognathic surgery in a single session. In this case, the authors opted to perform the grafting and implant procedures before the orthognathic surgery for the sake of better vascularization and osseointegration of the graft and implants, as well as reducing the risk of failure.
Then, proceeding final step, to the orthognathic surgery was performed with grafts and implants stable and osseointegrated, all of which increases the success rate of implant osseointegration as already demonstrated in other studies (Branemark et al., 1977;Chiapasco et al., 2007;de Avila et al., 2014;De Santis et al., 2012;Ferri et al., 2008;Gil et al., 2008;Jacobson & Starr, 2008;Keller et al., 1999;Ohba et al., 2015;Soehardi et al., 2015). It was also decided to reduce the chin, improving the patient's facial proportion and, consequently, facial aesthetics.
Even in patients where there is no need for correction of discrepancy in the relationship between arches, Le Fort I can be performed to increase bone levels, allowing dental implantation procedures in extremely atrophic upper jaws, which was not the situation in this case, where it was necessary to perform the onlay and inlay reconstruction of the maxilla using calvarial bone grafts and an anterior repositioning of the maxilla through orthognathic surgery. Due to the severity of maxillary atrophy, a considerable amount of bone was required for maxillary reconstruction and an increase of bone structures for implant installation. That type of autogenous bone graft is often not chosen because of temporary fragility in the skull after bone grafting.
During virtual planning, it was noticed that the position of the mandible in relation to the skull base was satisfactory. Therefore, the mandibular repositioning was excluded from the surgical planning, limiting the lower jaw intervention only to the chin reduction.
Extra care was taken during the periods of healing and osseointegration. When it comes to orthognathic surgery of the maxilla there is a total separation of the upper oral vestibule. Thus, decreased vascularization can happen in the detached tissue. It was decided to perform the implant installation previously aiming at greater vascularization and consequent oxygenation of the tissues, favoring safer healing and osseointegration of the bone blocks. After a period of one year, the success rate of the implants was 100% in this patient, which shows superior results to previous studies in which Le Fort 1 osteotomy was performed along with implant placement promoting ischemia of the area and contributing to the lower rate of implant success (Chiapasco et al., 2007;Ferri et al., 2008). However, literature shows reports of immediate loading implant placement with more satisfactory success rates which may be related to graft management, time of graft exposure to the external environment, fixation method, primary implant stability, patient habits such as smoking, professional management and the ability to follow instructions during the post-operative period (Rasmusson et al., 2012;Soehardi et al., 2015).
The success of the techniques used in this case does not limit further studies in more patients. Our case report has the limitation of having only one patient. More systematic clinical trial studies are needed to verify its real effectiveness in a statistically relevant number of patients. The planning described can be personalized according to the patient's needs. The patient is grateful for the proposed treatment and reports improvements in the masticatory functions which had a great impact on her social life and perceived self-esteem. The patient was instructed to seek care from a psychologist to better deal with the past difficulties during treatment and the visual change generated by the procedures. Orthognathic surgery promotes facial modification and nasal anteriorization due to maxillary advancement.

Final Considerations
Within the limitations of this case report, the association of calvarial bone graft, implant placement, Le Fort 1 osteotomy in addition to exogenous bone graft, and implant-supported fixed complete dental prostheses were favorable choices for this case. The multiprofessional approach offered security and comfort, according to the patient report.