Enforcing Dirichlet boundary conditions in physics-informed neural networks and variational physics-informed neural networks.

In this paper, we present and compare four methods to enforce Dirichlet boundary conditions in Physics-Informed Neural Networks (PINNs) and Variational Physics-Informed Neural Networks (VPINNs). Such conditions are usually imposed by adding penalization terms in the loss function and properly choosing the corresponding scaling coefficients; however, in practice, this requires an expensive tuning phase. We show through several numerical tests that modifying the output of the neural network to exactly match the prescribed values leads to more efficient and accurate solvers. The best results are achieved by exactly enforcing the Dirichlet boundary conditions by means of an approximate distance function. We also show that variationally imposing the Dirichlet boundary conditions via Nitsche's method leads to suboptimal solvers.

Correlation between Skp2 expression and nodal metastasis in stage I and II oral squamous cell carcinomas.

PURPOSE: The aim of this study was to investigate the role of S-phase kinase associated protein (Skp2) in the development of nodal metastasis and to assess its influence on prognosis in stage I and II oral squamous cell carcinomas (OSCCs). EXPERIMENTAL DESIGN: Seventy-one patients affected by OSCC (stage I-II) were observed in the period ranging from March 2003 to December 2006. The research was performed using immunohistochemical and histopathological analysis. RESULTS: The overall survival rate was 89.6% at 3 years, 87% at 5 years and 80.7% at 10 years. Patients with vascular or perineural invasion showed no statistically significant survival difference when compared with the ones with no invasion. The tumour depth of invasion did not prove to be related to the metastatic potential. Nine of the seventeen patients with Skp2 positive nuclei (≥20%) developed nodal metastasis. Conversely, only 6 of the 54 patients with a nuclear positivity lower than 20% developed a laterocervical metastasis (P=0.001). When comparing survival curves of Skp≥20% and Skp2<20% OSCCs, no significant P value emerged from the statistical analysis. CONCLUSIONS: This study is the first to report an important correlation between an Skp2 expression lower than 20% and the capability of the tumour not to develop nodal laterocervical metastases (P=0.001).

Induction chemotherapy followed by concurrent chemoradiotherapy in advanced head and neck squamous cell carcinoma.

BACKGROUND: A phase II study was carried out to investigate an induction regimen with cisplatin, paclitaxel followed by radiotherapy concurrent with weekly cisplatin for locally advanced squamous cell carcinoma of the head and neck. PATIENTS AND METHODS: Stage III-IV disease patients were eligible. Two cisplatin (100 mg/m2) and paclitaxel (175 mg/m2) courses were administered every 21 days followed by standard fractionated external beam radiotherapy (approximately 70 Gy), concomitant to weekly cisplatin (30 mg/m2). RESULTS: Thirty-five patients were enrolled: over 70% had unresectable disease with bulky lesions. Grade 3-4 neutropenia developed in 14% and G3 mucositis in 23%. Locoregional control was achieved in 51%. Median time to progression and overall survival were 10,7 and 17 months respectively; 2- and 3-year survival rates were 30% and 25% respectively. CONCLUSION: Our induction two-drug regimen followed by chemoradiotherapy with concurrent weekly cisplatin was well tolerated with low acute toxicity and good locoregional control and survival rate.

Total temporomandibular joint prosthesis as a surgical option for severe mouth opening restriction. A case report of a bilateral intervention.

Several conservative treatment approaches to the disorders of the temporomandibular joint (TMJ) have been described in the literature. Nonetheless, in a minority of cases not respondent to reversible conservative therapies a surgical approach to the TMJ is needed. In recent years, a total temporomandibular joint replacement with alloplastic prosthesis have been introduced as a treatment option in the presence of a severely damaged or mutilated joint, mainly resulting from severe joint diseases, as in the case of complex inflammatory-degenerative diseases, or failure of previous surgeries. The present paper described a case report of a bilateral temporomandibular joint replacement intervention in a female patient with severe mouth opening restriction and pain in the TMJ area. Also, a discussion of the potential indications for TMJ replacement has been provided, along with the description of the surgical procedure.

Parameters and outcomes in 525 patients operated on for oral squamous cell carcinoma.

PURPOSE: This report analyzed the outcomes of patients undergoing surgery for oral squamous cell carcinoma (OSCC) to identify the value of prognostic factors. MATERIAL AND METHODS: A total of 525 patients were studied who had undergone surgery for oral squamous cell carcinoma (OSCC) between 2000 and 2011, of whom 222 had received postoperative radiation-therapy (PORT) and or chemoradiation-therapy (PORTC). For each patient, personal data, histological findings, treatment and outcome were recorded and analyzed statistically. Survival curves were calculated using the Kaplan-Meier algorithm, and the difference in survival among subgroups was examined. RESULTS: The overall survival (OS) and disease-specific survival (DSS) 5-year survival rate in the 525 patients were respectively 71.38% and 73.18%. The differences in the overall survival and disease-specific 5-year survival were significant (p < 0.05) for age < 40 years, site of origin, N status, staging, grading, osseous medullar infiltration, and perineural invasion. In patients undergoing radiation therapy, only perineural invasion negatively influenced the survival prognosis. In 150 pT1 cases of tongue and floor-of-mouth cancer, an infiltration depth (ID) > 4 mm was statistically correlated with poorer prognosis. CONCLUSIONS: The results demonstrate an improvement in the 5-year OS and DSS rates during the past decade compared with the previous decade. Univariate analysis revealed that age, tumor staging, and lymph node involvement, extracapsular spread, grading, perineurial invasion, infiltration depth, and osseus medullary invasion were associated significantly with overall survival and disease-specific survival.

Transverse maxillary distraction with a bone-anchored appliance: dento-periodontal effects and clinical and radiological results.

In 29 adult patients presenting with maxillary deficiency, a bone-anchored palatal distractor (Surgi-Tec NV, Brugge, Belgium) was applied after osteotomy of the anterolateral walls of the maxillary sinuses, midpalatal suture, and, eventually, separation of the pterygomaxillary sutures. Expansion proceeded at a rate of 0.33-0.66 mm per day and the device was retained for 4-6 months for consolidation. Active orthodontic therapy was started after 8-10 weeks. The increment of arch width and the perimeter were evaluated using dental casts. Tooth thermal sensitivity and the periodontal side effects of treatment were monitored clinically after distraction, at device removal, and after 1 year. Bone healing was also investigated during the procedure using conventional radiological techniques. This experience confirms that transverse maxillary distraction is an effective technique in adult patients, leading to the formation of new bone. There were no noticeable intraoperative complications, but postsurgical periodontal side effects were documented. The procedure offers advantages over traditional teeth-borne appliances in terms of rapidity of treatment and the absence of mechanical forces acting on the teeth. Further evaluation is required to assess the long-term stability and periodontal consequences of this technique.

Correction of a mandibular asymmetry after fibula reconstruction using a custom-made polyetheretherketone (PEEK) onlay after implant supported occlusal rehabilitation.

This study describes an unusual case of mandibular asymmetry after fibula free flap reconstruction in a young man following major facial trauma that was corrected using a custom-made polyetheretherketone prosthesis. There is little information in the literature on the use of alloplasts to correct mandibular asymmetry as interest in 'aesthetic re-modelling' has traditionally focused on nasal, zygomatic and chin regions. This report demonstrates that this technique can be used successfully to address selected cases of mandibular asymmetry.

Hyperplasia of the mandibular coronoid process: long-term follow-up after coronoidotomy.

The aim of this study was to evaluate long-term results of treatment by intraoral coronoidotomy and prolonged physiotherapy in five patients with mandibular coronoid process hyperplasia. Five consecutive cases of coronoid process hyperplasia were studied (two unilateral and three bilateral) at the Department of Maxillo-facial Surgery of the University of Turin during the period 1985-1990. All patients were treated by intraoral coronoidotomy and given physiotherapy from the third postoperative day. This continued for an entire year. A clinical and radiological follow-up (average 39.4 months), in three cases over a 5-year period, was completed. Three months after the operation, all patients had achieved satisfactory improvement in mandibular interincisal opening. The mean value for mouth opening at the end of follow-up was 42 mm. Radiographic follow-up showed the presence of a coronoid process almost the size of the original, apparently united with the mandibular ascending ramus, with moderate dislocation and inclination posterior to the body of the zygomatic bone. The results of this study indicate that treatment of coronoid process hyperplasia by intraoral coronoidotomy, when combined with prolonged postoperative physiotherapy, gives satisfactory and stable long-term results in the correction of coronoid-malar interference.

[Schwannoma located in the tongue. A clinical case report]. / Schwannoma a localizzazione linguale. Presentazione di un caso clinico.

Schwannoma or neurilemmoma and neurofibroma are two tumors of the peripheral nerves originating in the nerve sheaths. Schwannoma account for just over 1% of benign tumors reported in the oral cavity. The tongue is unanimously considered the most frequent site at this level; however, the tip is the least affected part of the organ. The case of schwannoma reported here is the third observed with a lingual localization in 18 years by the Division of Maxillo-Facial Surgery of The Odontostomatological Clinic of the University of Turin. The case is of interest due the rarity of this pathology and the presence of non-significant symptoms for a presumed initial diagnosis. CASE REPORT. A 21-year-old woman was referred to our attention following the appearance two years earlier of a slowly growing swelling on the tip of the tongue. The patient complained of the fastidious presence, disturbance to mastication and phonation and occasional paresthesia of the tip of the tongue. The small mass, which was clearly evident on examination, was covered with normal mucosa. On palpation it had a hard-elastic consistency; it was slightly painful, smooth and partial mobile on surrounding levels. The patient underwent the surgical removal of the neoplasia under anesthesia. The mass was well capsulated and a good cleavage plane was easily found. The neoformation was yellowy grey, oval bean-shaped, measuring 1.9 x 1.3 x 1.1 cm. The histological diagnosis, confirmed by immunohistochemical tests, was benign Antoni's, type A schwannoma. The postoperative period was good an there was no recidivation during the course of a one-year follow-up. DISCUSSION AND CONCLUSIONS. Benign schwannoma, which are relatively rare in the oral cavity, represent a pathology which are often not taken into account during clinical practice. Symptoms which take the form of slight hypoesthesia and vague paresthesia may lead to the suspected diagnosis of this type of neoplasia. The final diagnosis is always made after a definitive histological examination. Differential diagnosis must be made in relation to malignant tumors (on the basis of anamnestic data relating to the speed of growth and clinical appearance of the neoplasia) and, above all, in relation to numerous benign neoformations based on epithelial and connective tissues (lipoma, fibroma, leiomyoma and adenoma). Treatment is always surgical: in the case reported here, the exeresis of the lesion also allowed its histological characterization (excisional biopsy). Surgery was conservative and did not require local or locoregional prophylactic measures. After the final histological diagnosis of schwannoma, the patient underwent a thorough general objective examination to check the presence of other characteristic signs of Von Recklinghausen's syndrome, have a probability of malignant degeneration ranging between 5 and 16%. Isolated schwannoma hardly ever become malignant and in general, if exeresis is complete, no recidivation occurs after surgery.

[Apicoectomy: comparison between 2 case series]. / Apicectomia: confronto fra due casistiche.

Data on 2 series of apicectomies performed in 1966-69 and 1978-82 respectively are compared. The comparison was based on clinical assessments and radiographic findings in patients given a repeated check-up a later date. Similar results were obtained in the two series, confirming the importance of scrupulous pre-operative endodontic treatment combined with the use of non-absorbable canal material. It is felt that this, combined with a scrupulously precise periapical surgical technique will ensure total success in all cases.

[Chondrosarcoma of the maxilla. A clinical case report]. / Condrosarcoma del mascellare superiore. Presentazione di un caso clinico.

Chondrosarcoma are malignant tumour originating in cartilaginous cells which tend to preserve their essentially cartilaginous nature throughout their evolution. They are rare at the level of the maxilla and mandibular. When localized in facial bone, chondrosarcoma follow a more aggressive pattern compared to those localized in long bones. They mainly affect individuals aged between 30 and 60 and show no sexual preference. In the majority of cases, chondrosarcoma have a relatively slow rate of growth. The only valid treatment is radical surgical removal. In overall terms, the prognosis in these patients is not good since the 5-year survival rate is less than 40%. During the period 1980-1992 only 5 cases of chondrosarcoma were diagnosed by the Division of Maxillo-Facial Surgery of the University of Turin. The authors considered it worthwhile to report the last case observed in a premaxillary localization given the advanced age of onset and the typical course of the pathology and treatment received. CASE REPORT. A male 83-year-old patient was referred to use due to a slow growing neoformation in the premaxillary region which had appeared approximately 5-6 months earlier. The patient had previously undergone the avulsion of residual upper teeth due to suspected "toothache". The neoformation filled the premaxilla, deforming the anterior middle portion of the palate and spreading towards the floor of the anterior nasal cavity. The gingiva of the upper alveolar crest presented ulceration with irregular edges and sanious bottom. On palpation the consistency was hard-ligneous and swelling, in continuity with the bone, was slightly painful. Incisional biopsy enabled the diagnosis of chondrosarcoma to be confirmed.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinico-therapeutic observations on a series of cases of odontogenic abscesses and phlegmons]. / Osservazioni clinico-terapeutiche su una casistica di ascessi e flemmoni odontogeni.

The authors review 561 patients suffering from odontogenic abscesses and phlegmons which were large enough to merit hospitalisation in the Division of Maxillo-Facial Surgery of the Odontostomatological Clinic at the University of Turin during the period from 1972 to 1990. The main features of these septic processes are evaluated: site, size, mode of growth and evolution, tooth responsible. Special attention is paid to the treatment performed: this was essentially based on antibiotic therapy and/or drainage of the abscess via a transcutaneous, transmucous or transdental route. The need to combine medical therapy with surgical drainage of purulent material was noted in the treatment of large infections; in many cases medical therapy alone was unable to guarantee the resolution of the pathology; on the other hand, surgical drainage alone in some cases led to the patient's recovery.

[Primary reconstruction of the anterior sublingual sulcus with a nasolabial flap after the resection of a malignant neoplasm]. / Ricostruzione primaria della pelvi sublinguale anteriore con lembo nasogenieno dopo resezione di neoplasia maligna.

The reconstruction of the loss of substance from the oral floor following demolitive cancer surgery aims to guarantee adequate tongue movement and the consequent preservation of phonatory and swallowing functions, as well as the possibility of using prosthetic rehabilitation. Large defects are resolved using musculocutaneous or free vascularised flaps, whereas smaller defects may be closed by first intention using alveolo-lingual suture. There are a number of drawbacks to this method: occurrence of fistulas immediately after surgery and secondary ankyloglossia. It is then necessary to resort to a second operation using dermoepidermic graft and plastic surgery of the oral floor to liberate the tongue. These problems may be resolved using a nasolabial flap. The flap can be prepared using either an upper or lower peduncle, it is relatively simple to perform and does not significantly prolong operating times. The contemporary dissection of the neck with ligature of the facial artery does not in our experience significantly influence flap vascularisation. The main drawback is the limited size of the flap (on average it is 6-7 cm long with a maximum width of 3-4 cm at the base. The upper edge is equally placed 7-10 mm from the medial side). The flap must be sufficiently thick to ensure an adequate blood supply to subcutaneous tissue, but the dissection plane must be sufficiently near the surface to preserve the facial nerve. It is important to prepare the graft bed so as to avoid creating tension after suture.(ABSTRACT TRUNCATED AT 250 WORDS)

[Use of Lyodura in fractures of the orbital floor]. / L'uso della Lyodura nelle fratture del pavimento orbitario.

After a brief review of reported techniques for the reconstruction of substance losses of slight or modest proportions at the orbital floor using autogenic, homogeneous, heterogeneous and alloplastic grafts, personal experience with this type of surgery employing lyophilised human dura mater is reported. It is considered that Lyodura can be considered the material of choice by virtue of its strength, handiness and the absence of tissue reactions. 38 fractures of the orbital floor were treated from 1980 to 1986 with osteosynthesis of the border and insertion of lyophilised dura mater to make up for bone loss. In the immediate postoperative period and in later controls, there was no evidence of complications or phenomena of intolerance to the material. The patients treated were followed up a short time later. Clinical and X-ray data confirmed the validity in time of the technique and material employed long-term.

[Clinico-surgical evaluation of supernumerary dental anomalies]. / Valutazione clinico-chirurgica delle anomalie dentarie in sovrannumero.

The pathology of extra teeth is evaluated on the basis of clinico-operative statistics for the years 1981-1985 and comprising 88 patients for a total of 115 treated teeth. The data obtained confirm the higher frequency of extra teeth in male patients. The most frequent site is easily the frontal sector of the upper arch. At that level, especially in males, two more or less symmetrical extra teeth are not infrequent. These data are in substantial agreement with the epidemiological data reported in the literature. Extra teeth are usually treated by surgical removal followed by orthodontic treatment to correct malformations caused by them and to recover the functional and aesthetic role of the upper front teeth.

[Removable prostheses with controlled distribution of forces on endosseous implants]. / Protesi rimovibile a distribuzione controllata delle forze su impianti osteointegrati.

The differentiated behaviour of dental abutments and alveolar mucosal tissues following functional loading has always created design problems in the field of removable partial prostheses. This situation of disequilibrium is particularly clear when natural piers are replaced by osteointegrated implants which are by definition unable to adapt to the masticatory load. In order to avoid this different behaviour, the authors feel it is advisable to use a removable partial prosthesis fitted with telescopic retention, defined as "controlled distribution of the forces", which can transfer the functional masticatory load to the osteointegrated implants and alveolar mucosal structures in a harmonious, balanced and homogeneous manner. The authors give a detailed description of the structure and working of this particular type of prosthesis, highlighting its advantages, namely: 1) controlled distribution of occlusal forces to osteointegrated implants and alveolar osteomucosal structures; 2) reduced number of implants required (2 are sufficient); 3) stability of prosthesis comparable to a fixed structure; 4) possibility of removing the latter with the advantage of maintaining oral hygiene around implants; 5) reduced size of prosthesis. Given that this type of prosthesis has been designed, realized and fitted to natural piers, with optimal clinical results, by the Dental Implant Department of the Dentistry Clinic of Turin University since 1969, the authors affirm that this prosthetic structure is particularly suitable in cases of edentulism with advanced maxillary atrophy.

[Odontogenic keratocysts. A report on cases with long-term histological review and clinical follow-up]. / Le cheratocisti odontogene. Presentazione di una casistica con revisione istologica e controllo clinico a distanza.

Keratocysts are cysts characterised by the keratinisation of the wall. Keratinisation may be observed in almost all types of cysts found at the level of the maxillary bones. The preferred location is the mandible. Keratocysts can belong to clinical symptoms of Gorlin's syndrome. In this case they are generally multiple and are associated with basocellular nevi and vertebral and costal anomalies. Keratocysts often relapse since their epithelium has a more rapid rate of growth than other maxillary cysts. Their correct treatment entails the radical enucleation of the cystic lesion or its marsupialization; the most aim is the complete removal of the cystic wall. We think that often is not necessary the use of more radical bone surgery (plugs, resections) except in those cases with multiple relapses. This paper reports a review of the clinical cases of keratocyst in the maxillary bone observed by the Maxillo-Facial Surgery Department of the Turin University since 1980 to 1991. The anatomo-pathological diagnosis of keratocyst has been introduced in Turin University after 1985; for this reason an histological review has been performed on the whole series of cysts with suspected characteristics observed during the past decade.

[Keratoacanthoma of the lower lip. A review of the literature and clinical case report]. / Cheratoacantoma del labbro inferiore. Revisione della letteratura e presentazione di un caso clinico.

The authors report a case of keratoacanthoma localized on the prolabium of the lower lip. They focus their attention on the difficulty of making a correct diagnosis and on the complexity of differential diagnosis with squamous cell carcinoma. After incisional biopsy of the lesion, treatment took the form of the complete excision of the neoplasm which is indispensable for a definitive diagnosis. The keratoacanthoma, although being an absolutely benign lesion, in fact requires complete exeresis in order to perform an histological examination of the entire neoplastic mass and thus definitively rule put the presence of squamous cell carcinoma. If correctly performed, the operation leaves very little scarring and satisfies the patient's esthetic and psychological expectations.

[Clinico-surgical evaluation of dental elements in bone inclusions]. / Valutazione clinico-chirurgica degli elementi dentari in occlusione ossea.

Dental inclusions are assessed on the basis of clinical and operating statistics relating to the years 1981-1985 and comprising 815 patients and 1445 treated teeth. The results confirm the predominance of inclusions among female patients and the prevalence of the mandibular site; the most frequently included teeth are the lower eighths followed by the upper eighths, the upper canines and the second lower premolars. Inclusions are bilateral in most cases. These findings are in substantial agreement with the epidemiological data recorded in the literature. The operating series shows that the type of surgical treatment varies with the localisation of the tooth (anterior or posterior), its relationship with contigous teeth and with the surrounding anatomical structures and the age of the patient. Teeth in the posterior sector are usually extracted. At young age, germectomy is carried out for orthodontic purposes; at mature age, teeth are extracted to prevent the formation of periodontal pockets and the aggravation of caries and their complications. On the other hand, for teeth in the anterior sector, surgery is usually merely the first stage in treatment and is followed by treatment of orthodontic type with traction, in view of the important aesthetic and functional role of the labial teeth.

[Relationship between injury dynamics and site of maxillofacial fractures. Comparative study of 100 cases]. / Rapporto fra dinamica del trauma e sede di frattura del massiccio facciale. Studio comparativo su 100 casi.

One hundred cases of facial mass fractures observed in the period April-September 1988 have been assessed using a clinico-anamnestic type investigation. Among trauma patients there is a prevalence of male patients aged between 10 and 30. Fractures located at the middle third and mandible occur in a practically equivalent number. Most traumas are the result of road accidents, following by falls. A good degree of correlation was observed between trauma aetiology and dynamics on the one hand and type and gravity of fractures on the other. Direct fractures, with greatest comminution of fragments prevail in high speed traumas; indirect fractures are most frequent in low speed traumas (cyclists and accidental).