Implant Prosthetic Rehabilitation in a Mandible Osteosarcoma Patient: A Clinical Report

Abstract

Introduction: Generally, after an oral oncological therapeutic process in which, unfortunately, surgery plays a fundamental role, a reconstructive and rehabilitative procedure should be initiated, seeking as far as possible to recover the patient’s vital functions (mastication, aesthetics, and phonetics). Case report: We present the case of a patient who successfully underwent treatment for mandibular sarcoma. After a disease-free period of one year, following oncological treatment, an intervention was performed for the insertion of dental implants into the fibula to subsequently rehabilitate the patient prosthetically. There were several challenges, including free-end edentulous space in the lower jaw with a depth of 18 mm on peri-implant tissues consisting of osteoseptocutaneous skin graft, hypotonic perioral musculature, and high aesthetic expectations of the patient. An overdenture with a titanium milled bar substructure with retentive prosthetic components was chosen for treatment. This implant-supported removable prosthesis was selected to facilitate cleaning, since the patient did not maintain oral hygiene habits. The patient was educated on using and handling the prosthesis, and the treatment objectives were achieved (to restore aesthetics and masticatory function). Conclusions: Removable prostheses are a valid alternative for oncologic patients and patients with unfavorable conditions for more complex implant-supported rehabilitation.

1. Introduction

Lip and oral cavity cancer ranks sixteenth worldwide in terms of incidence, with an estimated 389,485 new cases and 188,230 deaths per year according to World Cancer Statistics 2022 [1]. While osteosarcomas are the most common bone neoplasms among cancers located in bone tissues, only 6% are located in the jaw [2], and a low global incidence of 1–3 per million cases is reported compared to other types of cancer [3]. Its etiology is multifactorial, and risk factors could include germline mutations [4]. Its prognosis and treatment depend on the age of the patient, the status of the lymph nodes, the size of the tumor, the grade and stage, the primary site, and the status of distant metastases, according to results obtained using single-factor analysis and the log-rank test in Kaplan–Meier (K-M) analysis in cohort studies from 2010 to 2016 by the AJCC (American Joint Committee on Cancer) [5]. There is disagreement regarding the management of OSM (osteosarcoma); however, it has been established that wide tumor resection surgery with free margins is the indicated treatment for the management and improvement of the prognosis, thus avoiding metastasis [6] and patient mortality (

Table 1. Signs and symptoms of the oral cavity cancers [7,8].

Signs	Symptoms
Presence of masses of unexplained origin	Oral and oropharyngeal pain
Positive Garrington sign	Swelling of the jaw
Dental mobility in the affected area	Paresthesia
Erythematous appearance of mucous membranes	Nasal obstruction
Radiographical osteolytic, osteoblastic, or mixed lesion

). Therefore, the first objective of a treatment plan in patients with osteosarcoma is to focus on eliminating the pathology, stopping its progression or carrying out a treatment that eliminates or reduces pain to increase as far as possible the disease-free time, affecting the quality of life as little as possible.

The health professionals who generally identify the first signs and symptoms are dentists, since their manifestations are found in the intraoral area, which are oral and oropharyngeal pain, presence of masses of unexplained origin, positive Garrington sign, dental mobility in the affected area, and erythematous appearance of mucous membranes [7,8]. Therefore, the indispensable role of the dentist is to know the key signs and symptoms to be able to make an early diagnosis, together with the histopathological examination and interpretation of complementary tests, which are fundamental tools to improve survival rates and avoid major mutilations that are difficult to rehabilitate. Oral cancer frequently invades the jaws, both the mandible and the maxilla, so surgery aimed at their removal generates critical and deep defects, generally in the mandible which, due to their complexity, must be reconstructed with grafts whose donor sites are usually extraoral, such as osteoseptocutaneous fibula grafts. In 1975, the first case of mandibular reconstruction was performed specifically with a free fibula graft [9]. Later, its reliability was demonstrated, and thereafter, it became one of the most commonly used approaches due to its bone length, managing to regenerate lesions of up to 16 cm with a good prognosis and successful postoperative controls. This procedure was also chosen for its easy approach and the feasibility of performing multiple osteotomies [10]. Generally, we can observe a restoration of the anatomical structure and complete healing six months after performing a free fibula plate graft [11].

After the first phase, in which the patient can initially be considered free of disease, the rehabilitation of the patient continues its approach from the stomatological and prosthetic point of view. Currently, implant therapy is a reliable method to restore aesthetics and masticatory function, with survival rates of over 95% [12]. In this field, the arrival of dental implants has meant opening a new horizon for these patients, since it provides them with stability, support, and aesthetics; but, given the complexity of this type of patient, it also presents new challenges for the professional. The current criterion of success in implantology is not defined only by survival rates, but includes the implant/prosthesis complex, long-term mechanical stability, and tissue health [13]. A study on rehabilitation with implants in oncological patients who have undergone surgical tumor recession, even in irradiated patients, reported survival rates of dental implants of 92%, 84%, and 69% after 3.5, 8.5, and 13 years [14], while a more recent study reported, in its respective controls at 5 and 10 years, that the implants had a survival rate of 87.3% and 80.0% [15]. Another point to consider when planning implant rehabilitation in oncology patients is to wait for an adequate amount of time after radiotherapy (usually one year). When this time has elapsed, the survival rate of placed implants is relatively high (93.1% success) [16,17]. In addition, we must take into account that the success of implant therapy will depend on the previous diagnosis. The correct choice of the ideal type of prosthesis, its components and materials, and the use of a previous diagnostic wax-up that allows us to make a prosthetically guided plan will be the determinants of the success of our treatment in the long term [12].

Finally, authors such as Schoen et al. suggest that, for patients who have received radiotherapy, at least four implants are needed in the mandibular arch to support a prosthesis. Using this number of implants has been shown to relieve any undue pressure on the underlying soft tissues. In comparison with patients who have not received radiotherapy, where two implants have been shown to be sufficient to retain a complete mandibular prosthesis [18,19], this will depend on the extent of the edentulous space to be worked on and the location of the implants. Rogers et al. report that their patients are comfortable with the stability of the implant-supported prosthesis and the ease of oral hygiene [20]. This article focuses on the stage immediately after the first therapeutic objective; that is, once the patient has been treated and the progression of the underlying disease has been stopped, the rehabilitation or restoration of one hundred percent of the functions together with the facial and dental aesthetics of the patient, which may have been affected by the responsive treatment of the tumor, is proposed. This is because the total extension of the lesion is addressed, plus the free margins of around 3 cm, in addition to the teeth that are in the affected area, are also removed and, therefore, large bone cavities with extreme depth and diameter remain. Thus, the support for tissues that perform vital functions is removed. In this phase, the aim is to improve the quality of life of the operated patients, restoring basic functions, such as chewing, swallowing, pronunciation, and correct phonation; and, finally, to improve their self-esteem through prostheses adapted to the current conditions of their oral cavity, seeking to resemble the extracted tissues and blend in with the adjacent tissues. The literature shows few recent studies on this type of pathology and its technological application in the diagnosis of peripheral tissues to the lesion; for example, the evaluation of correct muscular function, stable occlusal contacts, and the incorporation of digital design software to create an efficient treatment plan. The use of implant-supported prostheses in patients with mandibular osteosarcomas is an ideal alternative, thus restoring occlusal and aesthetic parameters keenly sought after by patients.

2. Materials and Methods

Clinical Case

We present the case of a 22-year-old patient treated at the Virgen del Rocío University Hospital for mandibular osteosarcoma in 2021. The lesion was resected with radical safety margins, and the defect was reconstructed with a microvascularized fibula graft and titanium plate securing the area. The situation after one year of reconstruction, in 2022, can be seen in Figure 1 (orthopantomography).

At that time, the patient was transferred to the Faculty of Dentistry of the University of Seville for her prosthetic rehabilitation as a part of the activities sponsored by “Alejandro Padrós”, Chair of Oral Implantology.

An intraoral examination (Figure 2) showed caries in certain teeth of the upper jaw, persistence of tooth 53, inclusion of tooth 13, presence of teeth 16 and 26 outside the occlusal plane, and gingival recession in tooth 31 of the lower left central incisor. At the mandibular level, the skin palette covering the entire resected and subsequently reconstructed area was observed. During the elective period, several periodontal checks were carried out on the patient to improve her gingival health.

A scan of the occlusion was performed with the T-Scan Novus (Tekscan, Inc, Providence Highway, Norwood, MA, USA) (Figure 3) to evaluate the contact points present and how occlusal forces and pressure are distributed. The T-Scan results revealed high contact pressure points on the left second premolars and molars, specifically on lingual cusps 35, 36, and 37, with percentages of 20.6% to 32.4%, with zero contact points on the right side and a total of 98.9% of contacts on the left side.

The diagnosis of the health of the temporomandibular joint was taken into consideration by means of palpation and auscultation, as well as by observing the path of the opening and closing of the mouth, which did not reflect any apparent sign or symptom that showed alteration. However, in the extraoral examination, we evidenced labial incompetence and force on the part of the patient to exercise complete labial closure, together with an inclination of the lip on her right side and symptoms of mild pain in the cheeks. An exploration was carried out from the electromyographic point of view to rule out relevant alterations at the muscular level that impeded dental performance during treatment, such as development of implant surgery, tests, and installation of definitive prosthesis. Moreover, the balance of masticatory pressure exerted by the mandibular elevator muscles in both hemiarches was assessed and, in collaboration with the Department of Physiotherapy of the University of Seville, the electrical activity of the muscles involved in the masticatory function was evaluated. Furthermore, the temporalis, masseter, and pterygoid muscles were assessed bilaterally to detect synchrony or asynchrony in the movement of both sides of the face, to detect how many motor units were active, and to assess facial symmetry.

For this analysis, mDurance surface electromyography (sEMG) equipment (mDurance Solutions SL, Granada, Spain) was used for the following movements: standard mouth opening, maximum mouth opening, mandibular protrusion, and laterality. The pain threshold of all the muscles mentioned above was also assessed. The data obtained are detailed in

Table 2. The electrical activity of the temporalis, masseter, and pterygoid muscles is assessed bilaterally using surface electromyography (sEMG) in different movements.

Muscle	Side	Mouth Opening	Maximum Mouth Opening	Mandibular Retraction	Mandibular Protraction	Right Mandibular Diduction	Left Mandibular Diduction
		Myoelectric activity (µV)
Temporalis	Right	8.89	18.97	5.72	5.76	5.05	12.85
	Left	6.1	18.37	6.59	7.55	12.2	7.67
Masseter	Right	11.01	158.17	17.89	109.42	10.1	94.03
	Left	14.61	89.33	15.35	23.54	53.38	8.93
Pterygoid	Right	17.25	110.16	38.81	40.06	8.6	30.31
	Left	20.1	57.94	43.6	26.06	42.35	9.57

and

Table 3. Assessment of pain pressure threshold using algometry.

Muscle	Side	Pain Pressure Threshold (kg/cm2)
Temporalis	Right	1.62
	Left	1.38
Masseter	Right	1.23
	Left	1.05

. The extracted data did not show any relevant impediment to performing the prosthetic procedures, but they did indicate that there is no pattern of synchrony in the movement of the muscles that elevate the mandible.

Additionally, there is a decreased maximum opening of 32 mm, with which we can work but not in procedures that merit maneuvers that require more space in the most posterior area of the mandible. Therefore, it is recommended that the patient should begin physiotherapy treatment once the prosthetic phase is completed, oriented to activation techniques to re-establish synchrony. This is aimed at improving mastication and avoiding problems of degeneration or wear of the temporomandibular joint disc, protecting teeth and implants from parafunctional movements.

The results of the electromyogram (Table 2) indicated asynchrony in the masseter muscle on the right side, specifically in the maximum opening (158.17 µV on the right side; 89.33 µV on the left side), considering that this type of movement should be either equal or similar. We also identified asymmetry in the protraction movement since we obtained 109.49 µV on the right side and 23.59 µV on the left side, this movement being the one with the most significant difference. Differences were also found in the left diductive movement (right masseter, 94.3 µV; left masseter, 8.93 µV).

At the level of the pterygoid muscle, we found asymmetries in the maximum opening movement (110.16 µV on the right side; 57.94 µV on the left side) and in the mandibular diductive movement (muscle on the right side, 30.31 µV; left side, 9.57 µV).

These data indicate that there is no pattern of synchrony in the movement of the jaw elevator muscles. Therefore, it is indicated that the patient starts a physiotherapy treatment oriented to activation techniques to restore synchrony, aimed at improving her mastication, avoiding problems of degeneration or wear of the articular disc of the temporomandibular joint, and protecting teeth and implants from parafunctional movements.

Preoperatively, an intraoral scan was performed using the Medit I600 scanner (Medit, Seoul, Republic of Korea), which was incorporated into the patient’s CBCT (Planmeca ProMax^® 3D Classic, Planmeca Oy, Helsinki, Finland). We proposed the placement of four dental implants in the edentulous space where we had the fibula graft. The surgery was not guided but was digitally planned in software for the placement of virtual 3D surgical implants (Bluesky plan, Langenhagen, Germany) (Figure 4).

The factors that made guided surgery impossible were that the surgical box for guided surgery does not have sufficiently small-sized drills for the posterior sector and the reduced mouth opening. Therefore, it was decided to perform freehand implant surgery. The height of the edentulous space was wide (18 mm) and would be the main problem to overcome during the fabrication of the prosthesis. At the beginning of 2023, the intervention corresponding to the insertion of dental implants was carried out, in which four Klockner implants (Klockner, Barcelona, Spain) were placed along the edentulous area to restore lower teeth 41 to 46 (Figure 5).

An osseointegration period of 12 weeks elapsed before beginning the prosthetic phase; however, we encountered several setbacks, such as little or no oral hygiene for the patient, who presented high rates of calculus and bacterial plaque around the healing abutments and teeth, and two implants with mobility, the same ones that were evaluated to diagnose the degree of peri-implantitis. Therefore, they had an unfavorable prognosis and were removed, and we reconsidered the treatment plan, which initially involved attaching fixed prostheses to implants with an artificial gum portion, changing this option for a partially removable prosthesis, since it has been biomechanically proven that fixed prostheses with large edentulous spaces should not be produced with only two implants, and the patient did not want to undergo more surgeries. The patient was subject to a hygiene phase and periodontal and peri-implant control in order to keep a record of the remaining implants. In late 2023 and early 2024, extraoral and intraoral photographs were taken to begin the oral rehabilitation treatment, using the photographs to evaluate the loss of facial volume to be compensated (Figure 2, extraoral, and Figure 6, intraoral).

An intraoral scan was also performed using the Medit I600 scanner (Medit, Seoul, Republic of Korea) with i-medlocate attachments (Klockner, Barcelona, Spain) (Figure 7); however, it was not possible to obtain the expected precision in the peri-implant tissue area. This was due to the 18 mm depth from the incisal edge to the alveolar ridge and the patient’s reduced mouth opening, which made it difficult to manipulate the sensor head; consequently, meshes with holes were obtained in areas of important reproduction. Nevertheless, it was decided to print the result obtained from the intraoral scan in order to have a preliminary model.

The OBJ files were used to evaluate the case in Exocad (DentalCAD 3.2 Elefsina) software (Exocad GmbH, Darmstadt, Germany) (Figure 8) to identify the degrees of posterior implant inclination and how to correct this with intermediate abutments, as well as to carry out the design of the future teeth to determine whether cantilevers were necessary and which treatment options would work best for the patient. A trial wax-up was printed and applied (Figure 9), and the treatment plan was chosen according to the patient’s expectations, her cleaning habits and implant availability. Using the preliminary model obtained from the scan of the arches, an individual tray was made with polymerizable resin plates, Elite LC Tray (Zhermack SpA, Via Bovazecchino, Badia Polesine, Rovigo, Italy). The antagonist model was printed and could be worked on without any problems.

A single-time open tray impression was made with NV transfers (Klockner, Barcelona, Spain), using the addition of polyvinylsiloxane and Hydrorise Monophase (Zhermack SpA, Via Bovazecchino, Badia Polesine, Italy). The occlusal position was recorded with Occlufast CAD addition silicone (Zhermack SpA, Via Bovazecchino, Badia Polesine, Italy). It was sent to the dental laboratory Dentico (Seville, Spain) with the respective work order.

Once the parallelism was obtained using the Permanent (Klockner, Barcelona, Spain) indirect screwed intermediate attachments, straight in the implant of the anterior sector and 18 degrees for the posterior sector, passivity tests were performed. This was followed by a thickness and size test of the future structure using a prototype printed in resin (Figure 10) and, finally, wax-up tests, in which it was concluded that the lower first molar would be in crossbite to avoid occlusal overload and unnecessary cantilevers or overhangs.

The definitive titanium framework was sent for milling at the Archimedes Milling Center (Lérida, Spain), with K-Lock Vega NV retention abutments (Klockner, Barcelona, Spain) in the upper part of the bar. This method allowed us to obtain retention and stability for the prosthesis (Figure 11).

The overdenture with the desired dental position was sent to the Dentico dental laboratory (Seville, Spain) (Figure 12 and Figure 13). The final structure consisted of an internal mesh of reinforcement made of peek (Whitepeaks Dental Solutions GmbH, Weikenrott 17, 46499 Hamminkeln, Germany), resin teeth (methyl methacrylate) (MEGADUR, megadental GmbH, Seeweg 20, 63654 Büdingen), and a gum bun layered by composites of different shades (BREDENT, Tapton Park Innovation Centre, Brimington Road Chesterfield Derbyshire, UK).

Finally, after proceeding with the installation of the prosthesis, intraoral and facial photographs were taken to verify volume compensation in the lower facial third (Figure 14 and Figure 15).

When the definitive prosthesis was installed in May 2024, replacing teeth 41, 42, 43, 44, 45, and 46 (of which tooth 46 was the only one to remain in crossbite), using the T-Scan Novus (Tekscan, Inc., Providence Highway Norwood, MA, USA), we evaluated the occlusal contacts present again to verify the intensity in maximum intercuspidation of all the teeth. In this step, we found teeth with premature contacts in premolars of the opposite side, so an occlusal adjustment was performed to obtain a balanced occlusion. Once this procedure was performed, we re-evaluated and obtained occlusal stability in all teeth and points of equal intensity in the posterior sector. By contrast, in the anterior sector, the intensity was lower.

During the control and postoperative period, the patient was instructed on how to use and clean the prosthesis. Among the main indications, it was commented that there is a period of adaptation that can take between 21 and 45 days, since it is normal that the patient may feel a foreign body or excess volume, or even want to make counterproductive changes.

Exercises were sent for home practice to support dental treatment. The exercises sent were the following [14]:

Exercise 1: 1. Make an O with your mouth. 2. Smile, grimace, smile, grimace, grimace. 3. Open your mouth as wide as you can and stretch it out as much as possible. 4. Practice slowly ten times a day.

Exercise 2: 1. Stack four tongue depressors and secure them with a clean rubber band. 2. Open the mouth and slide the stack between the upper and lower teeth. 3. Determine the number of tongue depressors that can fit comfortably between the teeth. 4. Then, add a tongue depressor in the middle of the stack and allow it to stretch the mouth gently. 5. Gradually increase the number of depressors in the stack to stretch the mandibular opening. 6. Repeat at least twice a day.

Review at 6 months.

In Figure 16, you can see a schematic summary of the rehabilitation. In the review after six months, adequate occlusal rehabilitation can be observed (Figure 17) and a proper intra- and extraoral state (Figure 18 and Figure 19), compatible with bone health and successful integration of dental implants. (Figure 20).

3. Discussion

3.1. Surgical Treatment

Osteosarcomas are malignant neoplasms that represent 1% of head and neck tumors [21]. As it is a pathology with low incidence [5], we have found few cases described in the literature. Studies carried out on patients who have undergone resective surgery have a good prognosis, but surgery removes the lesion and free edges of up to 3 cm [6], which translates into extensive areas of the mouth. In the literature, we find that most cases correspond to patients who presented mild pain and swelling without symptoms of malignancy [22], and in whom the progression of the lesions reached 4 years. Therefore, like us, all authors focus on the importance of early diagnosis. Although grafts with titanium plate reinforcement are used, these are focused on restoring the function of the originally extracted bone but do not completely form the ideal space of the recessed bone, leaving facial asymmetries and missing teeth on the affected side as a side effect. Once the surgery that eliminates the underlying pathology has been performed, the treatment aim is to recover the missing teeth. For this phase, the prosthetic options include removable mucodental-supported prostheses, muco-supported implants, and fixed ones such as hybrid prostheses on implants. In a similar case presented by Garrido-Martínez et al. [23], four implants were placed 2 years post-radiotherapy. They obtained a 100% survival rate by performing a fixed plate-supported metal-ceramic prosthesis (31 to 36) without mucosal support. Although this prosthesis allows for better hygienization, it does not take into account the patient’s extraoral appearance and the replacement of facial volume [24].

The present study has certain limitations, due to the fact that the patient is referred from the Maxillofacial Surgery service of the Virgen del Rocío Hospital with a deficient state of oral health. She presented with a decapitation at the level of 53, multiple cavities, hypoplasia, and fracture of the incisors that caused a reverse curve of smile. Before starting the treatment of the fourth quadrant, the patient we explained to the patient the need to maintain an optimal state of oral hygiene. Deficient oral hygiene, the presence of plaque, and trauma as a cause of tooth loss are considered indicators of peri-implantitis risk [25]. However, because the State services booklet [Royal Decree 1030/2006, of 15 September, which establishes the portfolio of common services of the National Health System] does not cover conservative treatments, and the patient, for economic reasons, cannot afford the necessary treatments, it was decided to start with the current state of health, recommending extreme oral hygiene (use of dental floss, mouthwash with chlorhexidine, and application of 0.2% chlorhexidine gel).

Since our patient is young, with high aesthetic demands, the possibility of making prostheses on implants was evaluated so that she could feel more comfortable when carrying out her daily activities (

Table 4. Dates and details of procedures performed.

Year	Procedure
2021	Lesion was resected and reconstructed with fibula graft
2022	Periodontal control
2022–2023	Complementary exams and planification
2023	Surgery of 4 implants in the jaw
2023	Removal of 2 dental implants
2023–2024	Start with rehabilitation phase
2024	Prosthetic installation

). Since 2021, the patient had been chewing and grinding food with only one half of the arch. One of her wishes was to be able to eat correctly, since there were foods that she avoided due to not being able to chew them properly. By performing the digital evaluation and measuring the available spaces, we found that it was feasible to place four implants in the right sector of the jaw; since the patient had not undergone radiotherapy and the implant survival rate is as shown in the references [14,15], they became the best treatment option for the patient, who wanted something that did not have mobility during speech, mastication, and phonation.

Healing abutments were left connected to the implants and the appropriate controls were subsequently carried out. At each appointment, the patient continued to be instructed in oral hygiene teachings. It improved slightly but presented extrinsic stains on the occlusal faces of the first quadrant due to prolonged use of chlorhexidine gel in the fourth quadrant. Over the course of 12 weeks [26], it was indicated that the patient should undergo periodontal and peri-implant controls to ensure the elimination of calculus and bacterial plaque found not only in the abutments but in all the neighboring teeth. At the same time, the implants that were mobile were extracted. The variables that could have caused the failure of both implants are currently being studied, among which we can highlight the use of healing abutments [27,28,29] and the patient’s poor oral hygiene conditions [30]. Due to the loss of two implants and the patient’s diminished facial volume, it was decided that the ideal prosthetic option was an implant-retained prosthesis on a bar. The possibility of making an implant-supported prosthesis with only two implants was not feasible, as it would lead to occlusal overload due to the presence of a large cantilever and a small number of implants [31]. For the same reason, it was decided to use a bar instead of a Locator type supragingival anchoring system.

3.2. Rehabilitative Treatment

The stomatognathic system comprises bones, muscles, joints, and teeth. The first step to begin rehabilitation treatment is to confirm that these tissues are functioning correctly. For this reason, we began by analyzing the temporomandibular joint through extraoral examination, palpation, and auscultation, which did not reveal any apparent signs or symptoms that indicated any alteration. It was therefore decided to maintain the occlusion that the patient had previously had. Likewise, the state of the mandibular elevator muscles was evaluated because, when performing the extraoral examination, we could observe maximum mouth opening below 40 mm [32], as well as a closed mouth inclination and forced lip competence. The muscles were analyzed with surface electromyography in mandibular movements, for which we obtained the following results. The results of the electromyogram indicated asynchrony in the masseter muscle on the right side, specifically in the maximum opening (158.17 µV on the right side; 89.33 µV on the left side), considering that these types of movement should be either equal or similar. We also identified asymmetry in the protraction movement, since we obtained 109.49 µV on the right side and 23.59 µV on the left side, this movement being the one that presented the most significant difference. Differences were also found in the left diduction movement (right masseter, 94.3 µV; left masseter, 8.93 µV). At the level of the pterygoid muscle, asymmetries were found in the maximum opening movement (110.16 µV on the right side; 57.94 µV on the left side) and in the mandibular diduction movement (muscle on the right side, 30.31 µV; left side, 9.57 µV).

The extracted data did not show any impediment to performing the prosthetic procedures but did indicate that there is no synchronicity pattern in the movement of the muscles that elevate the mandible. Therefore, it is indicated that the patient should begin physiotherapy treatment, along with exercises at home, once the prosthetic phase is finished, oriented to activation techniques to re-establish synchrony, aimed at improving her mastication, and avoiding problems of degeneration or wear of the temporomandibular joint disc. The incident of the loss of two implants forced us to modify our initial treatment plan, which was to perform a hybrid prosthesis on implants, changing this option for a removable partial prosthesis on implants that was finally performed on two dental implants [33] that did not present any pathology and that were osseointegrated, following the York Consensus [34], which recommends a minimum of two dental implants in the edentulous jaw. Similarly, it was decided to leave the patient in an edge-to-edge occlusion to reduce intracoronal cantilever [35]. In this way, teeth 41, 42, 43, 44, 45, and 46 were replaced. Transepithelial abutments were used in the procedure to work at the gingival level, compensating for the angulations caused by the implants. A structure made of polished titanium was designed and manufactured to prevent bending movements during mastication [36,37] and to prevent the adhesion of bacterial plaque [38]. Dental aesthetics could improve the patient’s self-esteem. For the removable implant-supported prosthesis, the type of teeth that resembled her remaining teeth in shape and size were chosen, and care was also taken to ensure that no structure was visible when speaking or smiling. The prosthesis was intentionally made with a portion of pink gum, for which the color of the patient’s gum was recorded, and artificial gum characterization resin was added, giving an optimal result. Due to the limited space at the rear and the difficulty of sanitizing the rear sectors, it was decided to place a removable prosthesis, which is easy to clean as it can be completely sanitized upon removal of the prosthesis. The structure, made of polished titanium, also prevents the adhesion of bacterial plaque [37]. The patient was also reminded of the need to maintain optimal oral hygiene and to attend maintenance appointments.

Occlusion with removable prostheses should be physiological, allowing the distribution of forces between all the teeth in occlusion and allowing the supporting structures to remain in a good state of health [38]. Multiple authors advocate the maintenance of the existing occlusal relationship when the maximum intercuspidation is stable and there are no symptoms or signs of dysfunction [39]. Similarly, in eccentric movements, Terkla and Laney [40] recommended a balanced dynamic scheme in which there is contact of the posterior prosthetic teeth during mandibular movements. For those patients who have lost the anterior canine guidance, as is the case of our patient, they recommend the use of a group function or a unilateral balanced one [38,39].

4. Conclusions

Based on the results of this study, the following conclusions were reached: (1) Dental implants are a valid alternative for patients with oncological pathologies, but it should always be taken into account whether or not the patient has undergone previous radiotherapy, since the time at which the procedure is started will depend on this. (2) Prostheses on implants are a highly aesthetic and functional option that provides better stability, support, and resistance to patients with fairly large bone defects or atrophic jaws. (3) Design software not only provides professionals with a tool to develop a job but is essential in the planning of a surgical procedure, as long as the operator has experienced the learning curve beforehand and knows how to adapt to complications without compromising the success of the treatment. (4) The evaluation of peripheral tissues is particularly necessary in patients who have high aesthetic demands.