Automatic landmarking of cephalograms using active appearance models.

There have been many attempts to further improve and automate cephalometric analysis in order to increase accuracy, reduce errors due to subjectivity, and to provide more efficient use of clinicians' time. The aim of this research was to evaluate an automated system for landmarking of cephalograms based on the use of an active appearance model (AAM) that contains a statistical model of shape and grey-level appearance of an object of interest and represents both shape and texture variations of the region covered by the model. Multi-resolution implementation was used, in which the AAM iterate to convergence at each level before projecting the current solution to the next level of the model. The AAM system was trained using 60 randomly selected, hand-annotated digital cephalograms of subjects between 7.2 and 25.6 years of age, and tested with a leave-five-out method that enabled testing not only of the accuracy of the AAM system but also the accuracy of each AAM. Differences between methods were examined using the non-parametric Wilcoxon signed rank test. An average accuracy of 1.68 mm was obtained, with 61 per cent of landmarks detected within 2 mm and 95 per cent of landmarks detected within 5 mm precision. A noticeable increase in overall precision and detection of low-contrast cephalometric landmarks was achieved compared with other automated systems. These results suggest that the AAM approach can adequately represent the average shape and texture variations of craniofacial structures on digital radiographs. As such it can successfully be implemented for automatic localization of cephalometric landmarks.

Oesophageal food bolus impaction in elderly people.

INTRODUCTION: The diagnosis of food bolus impaction in the esophagus is based on the data obtained from the patient, clinical examination, radiographic diagnosis, and endoscopy. The aim of this study was to examine the influence of possible factors causing oesophageal impaction of food boluses in elderly people. MATERIAL AND METHODS: This retrospective study included six male and eight female patients treated at the Department of Ear, Nose, and Throat Disease in Novi Sad. RESULTS: Post-corrosive oesophageal stricture was diagnosed in 28.57% of patients and non-corrosive stricture was found in 21.43%. Total tooth loss was recorded in 64.29% of patients and 14.29% of patients had partial tooth loss. An impacted food bolus was located at a distance of 15-25 cm or 30-40 cm distance from the upper incisors in 42.86% of the study sample. DISCUSSION AND CONCLUSION: The impaction of food boluses in the esophagus is significantly higher in women, usually after 76 years of age. There is a positive correlation between the presence of oesophageal stricture and recurrence of food bolus impaction. Partial and total tooth loss is present in a high percentage but there is no correlation with the food bolus impaction. Impaction of food bolus was equally found in the upper and lower third of the oesophagus and it was usually meat. Radiographic diagnosis should precede each esophagoscopy. Esophagoscopy with rigid oesophagoscope is a reliable method for the extraction of a bolus of food from the oesophagus in elderly patients.

The significance of biometric parameters in determining anterior teeth width.

BACKGROUND/AIM: An important element of prosthetic treatment of edentulous patients is selecting the size of anterior artificial teeth that will restore the natural harmony of one's dento-labial structure as well as the whole face. The main objective of this study was to determine the correlation between the inner canthal distance (ICD) and interalar width (IAW) on one side and the width of both central incisors (CIW), the width of central and lateral incisors (CLIW), the width of anterior teeth (ATW), the width between the canine cusps (CCW), which may be useful in clinical practice. METHODS: A total of 89 subjects comprising 23 male and 66 female were studied. Their age ranged from 19 to 34 years with the mean of 25 years. Only the subjects with the preserved natural dentition were included in the sample. All facial and intraoral tooth measurements were made with a Boley Gauge (Buffalo Dental Manufacturing Co., Brooklyn NY, USA) having a resolution of 0.1mm. RESULTS: A moderate correlation was established between the interalar width and combined width of anterior teeth and canine cusp width (r = 0.439, r = 0.374). A low correlation was established between the inner canthal distance and the width of anterior teeth and canine cusp width (r = 0.335, r = 0.303). The differences between the two genders were highly significant for all the parameters (p < 0.01). The measured facial distances and width of anterior teeth were higher in men than in women. CONCLUSION: The results of this study suggest that the examined interalar width and inner canthal distance cannot be considered reliable guidelines in the selection of artificial upper anterior teeth. However, they may be used as a useful additional factor combined with other methods for objective tooth selection. The final decision should be made while working on dentures fitting models with the patient's consent.

[Early detection possibilities of obstructive sleep apnoea syndrome].

INTRODUCTION: Obstructive sleep apnoea (OSA) syndrome represents a significant medical problem due to numerous consequences that may follow it. OBJECTIVE: The aim of the study was to analyze morphology of the maxilla in children with mouth breathing, and to assess possible characteristics in persons with marked clinical features of OSA. METHODS: The sample comprised of 60 examinees aged from 8-10 years, all mouth-breathers. The following X-ray cephalometric parameters were measured: angle of maxillary pragmatism, cranial base angle, angle between the palatal plane and the anterior cranial base, maxillary length, distance from the most prominent labial surface of the maxillary central incisor to NA line, angle between the axis of the upper maxillary incisor and NA line. Following parameters were obtained from the casts: anterior and posterior width of the maxillary arch, height of the maxillary arch, index of the palatal height, as well as the apical base length. Assessed values were then compared to the corresponding norms. RESULTS: Compared to the corresponding norms, statistically significant lower values were determined for the following parameters of the sample: SpP/SN, AW, PW, AB. CONCLUSION: Analysis of the morphological characteristics of the maxilla in mouth breathing children showed characteristics also present in persons with marked clinical features of OSA syndrome, such as a narrow maxilla, insufficient apical base length, as well as the reduced angle of the palatal plane angle to the anterior cranial base. All these suggest a possible increased risk of developing OSA syndrome in children's later age.

[Contemporary methods and mobile denture cleansers and theirs significance for older population].

A dramatic increase in the number of people living in their seventies, eighties and nineties is associated with a loss of teeth and the use of mobile dentures. The aim of this paper was to highlight the consequences of poor denture hygiene on oral and general health in vulnerable elderly people, in long-term hospitalized elderly patients and in long-term institutionalized elderly in nursing homes. DENTURE DEPOSITS AND CONSEQUENCES OF POOR DENTURE HYGIENE: The number of bacteria living in the mouth is getting larger after putting denture on. Namely, a small "space" develops between jaw and denture, creating perfect conditions for bacterial growth. Denture becomes a "reservoir" of micro-organisms. Denture deposits such as bacterial plaque, fungi, tartar and remnants could be responsible for stomatitis prothetica, cheilitis angularis, inflammatory fibrous hyperplasia, halitosis (bad breath), dental caries in mobile denture carriers, mucositis and periimplantitis in mobile implant over-dentures carriers, accelerated destruction of denture materials for underlying, such as denture base soft liners, respiratory airways diseases, bacterial endocarditis and gastrointestinal infections. REMOVAL OF DENTURE DEPOSITS: It is recommendable to combine mechanical and chemical denture cleaning. Denture submersion into a commercial cleansing solution for less than one hour is an effective cleaning method. Commercial cleanser: specifically intended for dentures with metal parts should be used for those dentures. Commercial cleansers with a new component of silicon polymer, whose thin layer surrounds all denture surfaces and disables oral bacteria to agglomerate, are effective and useful. Preventive hygienic treatments are very important in hospitals and homes for the aged, bearing in mind that old and ill persons reside here. Those institutions are recommended to get equipped with ultrasound denture cleaners. IMPORTANCE OF WRITTEN BROCHURE ON PROPER DENTURE HYGIENE: Patients should be verbally instructed and showed about cleaning techniques, but also written instructions inform of brochure should be distributed in order to achieve better effects.

[Current trends in dental practice].

INTRODUCTION: This paper reviews recent trends in basic dental disciplines and advantages of new clinical procedures over conventional. PROSTHETIC RECONSTRUCTION OF DEPULPED TEETH: Post and core restoration is one of the most common treatment modalities applied when the remaining coronal tooth structure is not sufficient to provide the necessary retention form for restoration. Nowadays, the restoration of endodontically treated teeth is based on the use of materials with a modulus of elasticity similar to that of dentin. A NEW CONCEPT OF LIGHT INDUCED POLYMERIZATION OF ESTHETIC MATERIALS IN DENTISTRY: Polymerization contraction stress of resin based composite during light-activation process may be reduced by various illumination schemes. Successful curing depends on the calculated energy density values (spatial irradiance x irradiation period - J/cm2) rather than on light irradiance levels (mW/cm2). THE ASSOCIATION BETWEEN PERIODONTAL DISEASE AND GENERAL HEALTH: It is well documented that various systemic diseases have a profound effect on periodontal tissues. Recently, it has been speculated that periodontal disease may influence systemic health and represent the risk factor for cardiovascular diseases or adverse pregnancy outcomes. COMPUTER SYSTEMS FOR AUTOMATIC LANDMARK DETECTION: Computer systems, which will automatically identify relevant skeletal and soft tissue roentgencephalometric landmarks, will represent a great improvement in the field of orthodontic diagnosis. By using the Active Appearance Model, it is possible to identify most of roentgencephalometric bony landmarks with an average error well below 2 mm. CURRENT TRENDS IN CARIES TREATMENT: Chemomechanical caries removal was introduced as an alternative to conventional mechanical procedures. Its advantages are: selective removal of carious tissue, absence of pain, reduced need for local anesthesia and less potentially negative effects on the dental pulp. CONCLUSION: The introduction of the surgical operating microscope, microsurgical instruments, ultrasonic retrotips for root-end cavity preparation and new root-end filling materials opened a new era in periapical surgery, even on multi-rooted teeth, often called endodontic microsurgery.

[Anteroposterior jaw position in persons with skeletal class I]. / Anteroposteriorni polozaj vilica kod osoba sa skeletnom klasom I.

INTRODUCTION: Many authors point out that there are great differences in anthropometric studies due to racial, ethnic and population morphological characteristics. Facial type is a decisive factor when planning and setting objectives, as well as when choosing the mode of orthodontic treatment. The aim of this study was to determine the morphological characteristics of antero-posterior position of maxilla and mandible and determine the most prevalent facial type in children living in Vojvodina. MATERIAL AND METHODS: Sixty cephalograms of both males and females, with skeletal class I and harmonious facial profile, were digitized and the following skeletal measurements were calculated: SNA, SNB and ANB angles. For comparative analysis, characteristics of craniofacial complex of the tested population were compared to Bolton standards from the Broadbent-Bolton longitudinal growth study. RESULTS: A statistically significant difference of both maxillary and mandibular prognathism were present when compared to Bolton standards. This indicates more retrognathic viscerocranial structures, and more posteriorly divergent profiles (SNA=81.7 degrees; SNB=78.23 degrees). CONCLUSION: Differences identified in craniofacial parameters in relation to Bolton standards show that one should carefully consider the risk of altering facial esthetics of patients from Vojvodina with extraction treatment. Whenever possible, give priority to early non-extraction treatment, in order to reach the best possible end-result within the given facial type, preserving facial esthetics.