LOSSES OF SUBSTANCES. Pr Maachou
I/DEFINITION: PDS are more or less significant destruction of skin and/or mucous and bone tissue . PDS have five main causes. They can be of congenital, infectious or traumatic origin. However, these losses of substances are most often the result of surgical excision of maxillary tumor. Losses of substances are classified according to the resected bone portion or the prosthetic objective. Conventional techniques make it possible to produce so-called immediate, temporary or use obturator prostheses. In all cases, taking an impression is delicate due to the risks of reflux of the material into the cavities and the limitation of the oral opening. In addition, there is a risk of altering the sensitive and weakened fibro-mucosa when re-inserting the impression. These anatomical obstacles make clinical procedures uncomfortable for the patient and complicated for the practitioner. Only PDS at the maxillary level will be treated.
II/ Etiologies of maxillary substance loss:
Endo-oral substance losses cause tissue continuity leading to communication between the oral cavity and the nasal fossae and/or the sinus. They are very heterogeneous both from the point of view of the anatomical and morphological situation, as well as in terms of their extensions.
1-Congenital factors
Face formation occurs between the 4th and 10th week of gestation by development and fusion of the five facial buds. The nasal buds and maxillary buds unite and fuse to form the upper lip, maxilla, and primary palate around the 6th week of intrauterine life. The palatine process derived from the maxillary bud joins the palatine process on the opposite side, and the vomer derives from the frontal bud between the 6th and 9th week to form the secondary palate. The spectrum of congenital facial defects (or clefts), including cleft lip and palate, results from the failure of one of these buds to fuse properly with the neighboring one. The etiology results from a multifactorial association of genetic and environmental factors.
2-Traumas
In civilian maxillofacial trauma, it may involve loss of maxillary substances following accidents at work, at home or in sports. Ballistic trauma (attempted autolysis and homicide) can also result in complex damage and require major surgical reconstruction.
3-Other iatrogenic causes
These are losses of substances following osteonecrosis (most often mandibular) caused by arsenic derivatives or bisphosphonates. We can also report phenomena of maxillary necrosis due to infections such as herpes virus, mycotic infections or infections by the acquired immunodeficiency virus (AIDS).
4-Tumor pathology
The excision of tumors in the upper jaw results in significant loss of substances. This is the most preponderant etiology in maxillofacial prosthetics. Indeed, tumors of the upper aerodigestive tract (UADT) represent 30% of the total UADT tumors. The most frequent malignant tumors in the palatine vault and gums are squamous cell carcinomas. Treatment by excision gives rise to an orosinusal (BSC) or orosonasal (BNA) communication.
There are several risk factors for cancer, including: tobacco, alcohol, chronic irritation of the mucosa, deficiency states, immunocompromised conditions (transplant patients, patients with the AIDS virus), drug use (cocaine, etc.). Malignant tumors affecting the maxilla can have two distinct origins: they can follow the development of a tumor of the upper aerodigestive tract originating in the oral cavity or constitute extensions of tumors affecting the sinus cavities. Thus, the anatomical structures affected during maxillectomies vary according to the extent of the cancerous lesion. These two types of tumors have different characteristics from an etiological and clinical point of view.
5-Surgical excision
The choice of the therapeutic indication for maxillary tumors is based on a multidisciplinary meeting bringing together all the health professionals concerned. Thanks to an adapted oto-rhino-laryngological clinical examination as well as a computed tomographic (CT) imaging examination, the tumors can be analyzed from an anatomical point of view. Thus, each patient is treated on a case-by-case basis according to the characteristics of the tumor and their general condition. Surgical treatment of the tumor by excision is the treatment of choice for tumors affecting the maxilla. The treatment will be guided by several factors, including histology, the possibility of resection, and the presence of cervical and distant metastases. Thus, surgical excision can be very mutilating and concern the entire maxilla or extend to the level of the anatomical elements mentioned above such as the nasal, sinus or orbital cavities. The surgeon must ensure that the dental capital and the main pillars of the facial mass are preserved as best as possible in order to ensure future oral rehabilitation. In addition, a clinical examination carried out in time will often provide a better prognosis. Indeed, the late development of cervical metastases is considered an unfavorable factor.
III/Consequences of substance losses
The consequences of PDS are numerous and varied. Indeed, surgery for tumors affecting the maxilla is most often mutilating, in a region of great functional importance and in the life of relationships. This leads to communication between the oral cavity and the nasal cavities or sinuses and can also involve the skin and muscle areas in the case of extensive maxillary tumors.
1-Functional disorders
The main functional disorders are:
– Difficulty speaking and phonating due to the leakage of exhaled air into the nasal passages. The voice becomes nasal with sometimes incomprehensible words.
– Very difficult feeding due to the reflux of food and liquids into the nasal passages and sinuses (false passages). Large losses of substances may result in the placement of a nasogastric tube for parenteral nutrition.
– Masticatory disorders due to occlusal asymmetry as well as a limitation of mouth opening.
– Loss of mobility of the facial muscles. Following surgical excision, many orofacial muscles can be affected and cause loss of mobility in the face.
– Ophthalmological problems: given the proximity of the orbital floor and the maxillary bone, visual disturbance and eye static may occur after significant excision.
– Respiratory disorders. In fact, the presence of CBN makes it impossible for the nasal respiratory mucosa to filter, humidify and warm the exhaled air.
– Salivary disorders. Radiotherapy treatment causes hyposialia due to the systematic irradiation of the salivary glands. This can result in xerostomia and increased weakening of the oral mucosa associated with disturbed oral flora. We also find rapidly evolving carious lesions due to a decrease in salivary pH and a change in the quality and quantity of saliva. Finally, at the skin level, there may be manifestations such as erythema and desquamation. These symptoms may be accompanied by sensitivity to touch and itching.
2-Infectious disorders
Chronic infection of the sinus cavities may occur in cases of narrow oral-sinuso-nasal communication. This risk of infection may be related to poorly adapted dental prosthesis.
3-Aesthetic disorders
The aesthetic repercussions are caused by sagging of the lips and cheeks following the loss of substances causing facial asymmetries. These disorders are all the more significant as the excision is extensive. Scar bands may also persist after surgery.
4-Quality of life
The concept of quality of life is defined by the World Health Organization (WHO) as “a state of complete physical, mental and social well-being”. In the context of patient care, treatment must demonstrate that it improves the biological control of the tumor and the patient’s lifespan but also their quality of life. This physical, psychological and social concept is specific to each individual.
IV/Classifications: Brown classification modified by Okay in 2000.
The vertical component is defined by the numbers 1-4. (fig2)
Class 1: low maxillectomy without oro-antral communication (no involvement of the sinus mucosa)
Class 2: moderate maxillectomy with communication but without involvement of the orbital floor
Class 3: high maxillectomy with involvement of the floor and without involvement of the orbital contents
Class 4: Total maxillectomy with complete exenteration
LOSSES OF SUBSTANCES
The horizontal component is characterized by the letters a, b or c.
a: unilateral alveolar maxillectomy
b: bilateral alveolar maxillectomy
c: total alveolar maxillectomy
LOSSES OF SUBSTANCES
. (fig2) Brown classification published modified by Okay in 2000.
V/ Treatment:
- Surgical rehabilitation: Surgical rehabilitation of maxillary substance losses corresponds to the surgical closure of the site by a flap or a graft . It is a technique in constant progress which makes it possible to recreate certain anatomical structures and to restore the patient’s orofacial functional capacities, as well as a certain aesthetic.
- Advantages and disadvantages of surgical rehabilitation
The advantages : the watertight and definitive closure of the loss of substance, offering optimal comfort.
the disadvantages : the absence of direct control of the excision cavity which requires frequent radiographic monitoring,
- the difficulty of the technique and the time of the surgical procedure,
the high cost, the morbidity of the donor site, and the persistence of phonatory problems. In addition, the adaptation of dental prostheses, due to the unfavorable architecture of the reconstructed tissues, is often difficult, which sometimes requires the use of bone tissue grafts allowing the placement of osteointegrated implants.
- Surgical reconstruction procedures :
Surgical reconstruction methods vary depending on the
clinical situation, and may use different types of tissues taken
locally or remotely.
- Local plasty: Reconstruction by local plasty is intended for modest-sized substance losses. They are based on the principle of closing the substance loss by sliding plasty of buccal mucosal flaps, which preserves the vascularization. These may be tongue or pharyngeal mucosa flaps. Skin flaps can sometimes be used in the case of substance loss affecting the skin tissues of the face and nose.
- Locoregional plasty: Locoregional plasty reconstructions are intended for larger tissue losses. This reconstruction technique consists of transferring a pedicled and vascularized, muscular or musculocutaneous flap from a regional area to the level of the tissue loss. It is intended for tissue losses that cannot be repaired by local tissue plasty. This may involve:
- nasolabial flap,
- of buccinator flap,
- temporal, frontal or cervical flap for example.
- Bichat’s fatty flap
- Remote plasty : Remote plasty consists of taking free vascularized flaps, at a distance from the recipient site. This is a long and complex surgical operation that requires the performance of micro anastomoses:
- temporal flap
- iliac flap
- Prosthetic rehabilitation : the obturator prosthesis is made up of two parts:
- a palatal plate made of resin or cast metal and which may or may not include prosthetic teeth,
- an obturator itself which will be made of hard resin or flexible material, and which will or will not be attached to the plate: we then speak of a single-block prosthesis or a multi-stage prosthesis.
The obturator prosthesis is used to rehabilitate the loss of substance caused by the cancer excision surgery. The objective is to close the bucco-sinuso-nasal communication in a watertight manner. This device is essential to restore functions, aesthetics – by supporting soft tissues – and improve the quality of life of patients. The obturator prosthesis aims to rehabilitate the loss of substance and is composed of two distinct parts: a palatal plate and the maxillary obturator. The palatal plate made of resin or metal is used to ensure the retention, stabilization, and support of the prosthesis. It may or may not have prosthetic teeth. The second corresponds to the obturator which rests on the upper face of the plate. It is in an intra-maxillary position in order to fill the loss of substance. This obturator may be made of resin or flexible material. It is difficult to give a precise technique for producing a palatal obturator with a given defect.
a-The immediate obturator prosthesis
Also called a surgical obturator, this prosthesis is put in place intraoperatively and is worn by the patient a few weeks before the temporary prosthesis is made. Its placement involves a preoperative consultation in order to obtain all the information useful to the entire multidisciplinary team: creation of the medical file, taking of primary impressions, recording of maxillomandibular reports, etc. This step allows an initial contact with the patient, particularly on a psychological level.
A primary alginate impression is therefore made following this consultation. It allows the future prosthesis support corresponding to the loss of substance caused to be made. The laboratory makes a palatal plate on the resected model, retention being ensured by rider hooks on the remaining teeth on the model. It should be noted that retention riders can be placed on the palatal plate opposite the resected area. This technique is used if the intended filling material is a silicone.
After excision surgery and filling of the undercuts with Vaseline gauze compresses, an impression with a delayed-setting acrylic resin (Fitt by Kerr®) is made in order to make the immediate obturator. The palatal plate serves as a support for the filling material. After the material has set, it is then removed with its obturator, corrected with a scalpel, then placed in the mouth. This will facilitate the healing phase.
b-Provisional or semi-immediate obturator prosthesis
The temporary obturator prosthesis is made within eight days to two weeks following the operation, when an immediate prosthesis could not be made preoperatively. The time taken to make the temporary prosthesis will obviously depend on each patient and will be assessed on a case-by-case basis. It is indicated when the multidisciplinary team does not have the time to make an immediate prosthesis. The lack of proximity between the prosthesis and surgery unit also favors the creation of a temporary prosthesis. It is put in place in a hospital environment to avoid a possible risk of hemorrhage. The disadvantage is that the patient can only eat parenterally between the operation and the placement of the obturator prosthesis. The steps for making the prosthesis are similar to those used for an immediate obturator but it can also be made from a pre-existing partial resin denture.
c-Transitional obturator prosthesis
The temporary obturator prosthesis is placed 3 to 4 weeks after the operation. Its purpose is to gradually restore function and aesthetics as well as to evolve over time in accordance with healing. It can be made after anatomofunctional impression or be relined from the immediate obturator prosthesis. Indeed, depending on the case, the prosthesis can be relined at the obturator level with a delayed-setting resin that will improve healing, comfort and sealing. However, the patient should not be left without their prosthesis for too long so that they can eat. Effective communication within the multidisciplinary team is essential here.
d- Obturator prosthesis in use
The usual prosthesis can only be considered 3 months to 1 year after the operation. This period corresponds to the dimensional changes due to tissue remodeling and complete healing. Healing is considered satisfactory if the excision cavity does not present any infection and there is no scar retraction at the limits of the CBN areas. This prosthesis remains modifiable and aims to restore the occlusion, aesthetics and function. The conventional technique is a solution of choice to allow the creation of palatal obturators. But in certain cases it is not sufficient to compensate for the consequences due to the loss of maxillary substances. The multidisciplinary team can set up adapted surgeries such as grafts or methods related to implantology.
Advances in the field of three-dimensional medical imaging offer interesting prospects for the production of palatal obturators.
There are two types of shutter:
Rigid obturator attached to the palatine plate.
Soft obturator dissociates from the palatal plate.
The choice will be made based on different clinical criteria.
Rigid resin obturators are used in patients with teeth or limited loss of substance .
Soft silicone obturators are preferred in edentulous patients or for extensive loss of substance. This obturator will be secured:
- resin palatal plate with shaped hooks in patients with weak teeth,
- metal plate with hooks cast into the patient with wide teeth;
the shutter will be hollow in order to be as light as possible.
- The primary quality of a standard obturator prosthesis is to be light.
Choice between soft or rigid shutter :
LOSSES OF SUBSTANCES
- Choice between multi-stage prosthesis or single-block prosthesis : will depend on:
- of the importance of the loss of substance + surface condition of the irradiated tissue + the mouth opening .
- Generally speaking, when possible, monobloc prostheses are preferred because they age better, are more functional and easier for patients to use than the increasingly complex multi-stage prostheses .
- In addition, they are more easily rebased and retouched.
- However, the multi-stage prosthesis is compatible with limited mouth opening.
LOSSES OF SUBSTANCES
Untreated cavities can damage the pulp.
Orthodontics aligns teeth and jaws.
Implants replace missing teeth permanently.
Dental floss removes debris between teeth.
A visit to the dentist every 6 months is recommended.
Fixed bridges replace one or more missing teeth.