The Biomechanical Impact of Loss of an Implant in the Treatment with Mandibular Overdentures on Four Nonsplinted Mini Dental Implants: A Finite Element Analysis.

The aim of this study was to evaluate the biomechanical impact, in terms of stress and displacement, at the level of a mandibular overdenture, on four mini dental implants (MDIs) after the loss of an implant. A three-dimensional virtual model was obtained by scanning the overdenture, and a biomechanical analysis was carried out, using the finite element method (FEM). The displacements of the overdenture and the equivalent von Mises stresses were evaluated using logarithmic scales. In the case of a mandibular overdenture on four MDIs inserted in the interforaminal area, the frontal loading generated the lowest values for the von Mises stresses, and the bilateral loading generated the least displacement when two implants were inserted in the canine area and two in the molar area. The highest von Mises stress was observed during frontal loading in the situation of the mandibular overdenture on four MDIs, two of which were inserted in the canine area and two in the molar area, following the loss of an implant in the canine area. The largest displacement was noted in the mandibular overdenture on four interforaminal MDIs during unilateral loading, following the loss of a distally inserted implant. The FEM analysis showed aspects that correlated with clinical observations, with predictive value. The concentration of von Mises stresses, and the occurrence of some displacements of the prosthodontic restoration, can explain the emergence of some complications in the overdenture's biodynamics, and the increased risk of fracture. Complications can be prevented by choosing a certain number of implants and a topographical distribution correlated with biomechanical aspects, and by proposing a correct occlusal scheme with optimal functional loading.

Perception and attitudes of dentists regarding the complications of conventional acrylic dentures and overdentures supported by teeth or implants.

This study aimed to assess the perception of dentists on the complications associated with prosthodontic treatments with acrylic dentures and overdentures in partially or complete edentulous patients. The study analyzed the complications of acrylic dentures and overdentures using a questionnaire with 24 open or closed questions, with single or multiple answers. The participants were 63 dentists, mostly women (77.8%), aged between 30 and 39 years old (52.4%), more than half of them with a clinical experience of less than 15 years. The main complications encountered were: lesions of the oral mucosa (52.4%), lack of maintenance (44.4%) or stability of dentures (39.7%), fracture of acrylic bases (14.3%), and detachment of attachment systems (44.4%). The complete maxillary acrylic dentures fractured most often (38.1%), frequently on the midline (58.7%), the main causes being accidental fall, masticatory stress, or lack of stability of the dentures. The most common intervention to correct the complications of dentures was the repair of fractured acrylic bases (33.3%). The study exposed that dentists are aware of the possible complications of acrylic dentures, which they correlate with the peculiarities of oral structures, but also with some deficiencies of prosthodontic restorations, materials and technologies. Maxillary acrylic dentures, overdentures, and partial acrylic dentures have a high risk and fracture rate, but the use of new technologies and materials can reduce the complications rate of acrylic dentures and overdentures.

The perceived association of oral diseases and general pathology among doctors of different specialties.

This study aimed to highlight the perceived associations between general and oral pathology, among clinicians of different specialties. Data was collected through a questionnaire with 22 questions, with single or multiple answers, to 88 dentists, general practitioners, or pediatricians. The majority of participants were women (89.8%), aged between 30 and 39 years (52.3%), with a professional experience mostly under 10 years (61.3%). Many doctors considered that there was an association between oral and general pathologies (39.8%). The most common general pathologies associated with oral pathology were digestive disorders (n=21, 23.9%), followed by cardiovascular, genetic, endocrine and metabolic, neuropsychiatric, respiratory, hematological, immunological, and oncological pathologies. Tooth decay was mainly found in patients with digestive, respiratory, or neuropsychiatric disorders, and periodontal disease was more common in patients with obstetric disorders. Diseases of the oral mucosa, such as canker sores and gingivostomatitis, were more common in patients with digestive pathology, endocrine and metabolic, or reproductive disorders. The study pointed out that physicians, regardless of their medical training, often observed a relatively rich general pathology associated with oral conditions. It is important to differentiate between primary and secondary oral pathology, associated with general pathology and medication, establishing a correct diagnosis of the disease and treatment according to general or oral diseases and their manifestations.

Food Bolus Properties in Relation to Dentate and Prosthetic Status.

The objective of this study is to evaluate food bolus properties (mass, moisture content and food comminution) in patients wearing fixed or removable dental prostheses. Methods: A cross-sectional study was conducted on a convenience sample of patients aged at least 55 years old. Patients chewed a 10 g sample of fresh raw carrot until they felt ready to swallow. The mass of the food bolus was determined as collected and after drying. Food comminution was assessed by the multiple sieve method. Results: Patients with fixed prostheses compared to those with removable prostheses registered a similar mass of food bolus as collected (4.40 g vs. 4.60 g; p = 0.856); a higher mass of dried food bolus (3.46 g vs. 0.86 g; p < 0.001); lower moister of food bolus (24.65% vs. 82.35%; p < 0.001); and better food comminution (mass of smaller particles, of size below 2 mm, represented 65.93% vs. 20% of dried food bolus). In removable denture wearers, food comminution was slightly better in partially than in completely edentulous patients, and rather similar in completely edentulous patients with either implant overdenture or complete denture in the mandible, and complete denture in the maxilla. Conclusions: The current results suggest that food bolus properties are dependent on the dentate and prosthetic status.

Anatomical features and prosthetic considerations of edentulous patients with mandibular reconstruction with autograft performed more than 40 years ago.

In this manuscript there are presented two cases, both with mandibular reconstruction with autograft harvested from the iliac crest, performed more than 40 years ago, but with different bone defect etiology, i.e., mandibular dysplasia and mandibular fracture, both having currently extensive tooth loss in the mandible, being in need for prosthetic rehabilitation. These cases confirm that reconstructive surgery of mandibular bone defects with autograft from iliac crest has a satisfactory long-term outcome, providing acceptable conditions for prosthetic rehabilitation. Bone resorption in the grafted area seems to be related to the etiology of bone defect, and influenced by preservation of dental occlusion and masticatory function. Reconstructive surgery made decades ago has sequelae that increase the difficulty of prosthetic treatment of edentulous patient, that need to be proper evaluated and included in the treatment plan, in an individualized approach, in order to obtain an acceptable functional outcome.

Clinical study on thermography, as modern investigation method for Candida-associated denture stomatitis.

Candida-associated denture stomatitis is an infectious inflammatory condition of the oral mucosa, with frequent recurrences. The aim of this study was to assess the use of infrared thermography as investigation method for Candida-associated denture stomatitis (as inflammatory disorder of the maxillary denture bearing area), by comparing disease and non-disease groups. An observational study was conducted on maxillary edentulous patients treated by acrylic dentures, with and without Candida-associated denture stomatitis. Diagnostic test methods used were clinical examination for denture stomatitis and conventional microbiological culture method for oral candidiasis. Thermography analysis of the maxillary denture bearing area was made using the ThermaCAM PM350 infrared camera (Inframetrics, Flir Systems) and ThermaGram Pro 95 software, data being acquired by usage of standard protocol of thermographic registrations. The sample included 52 patients, 21 with and 31 without Candida-associated denture stomatitis. The temperature of the maxillary mucosa corresponding to the denture bearing area was found to be statistically significantly higher in Candida-associated denture stomatitis (mean 36.20°C), compared to healthy oral mucosa (mean 34.85°C). The thermal threshold value of 35.44°C was identified as best differentiating a pathological from normal state of the maxillary mucosa corresponding to the denture bearing area. In conclusion, infrared thermography, a rapid non-invasive investigation method, has the premises to bring valuable data in inflammatory disorders of the maxillary denture bearing area, as Candida-associated denture stomatitis that may be used for screening, diagnostic or monitoring purposes.