Timing of emergence of the first primary tooth in preterm and full-term infants.

Variations in the timing of emergence of primary teeth are under strong genetic control, but there is also a significant contribution from external factors. The aim of this study was to evaluate the influence of preterm birth, birth weight and length, and feeding practices during the first 6 months of life on the timing of emergence of the first primary tooth. Data on pregnancy duration, birth weight and length, feeding practice, time of emergence and first emerged primary tooth were collected by electronic questionnaires. The study included 409 parents and 592 children of both genders. The sample was divided into two groups according to pregnancy duration (<37 weeks and ≥37 weeks), three groups according to feeding practice (exclusively breastfed, exclusively bottle fed, and a combination of breast feeding and bottle feeding), three groups by birth length (<50, 50-53, >53cm), and four groups by birth weight (<1500, 1500-2500, 2501-3500, >3500g). Data were analyzed considering chronological and postmenstrual age-which is the gestational age plus the infant's chronological age at the month of emergence of the first primary tooth. The mean time of first primary tooth emergence was 7.55±2.67 months when chronological age was considered. The first emerged tooth in most cases was a lower incisor (82.33%). There was a statistically significant difference in the timing of the first tooth emergence between preterm and full-term groups when chronological age was considered (p<0.005). However, no difference was found when age was adjusted. The age of emergence of the first tooth differed significantly when feeding, weight, and length groups (p<0. 05) were taken into account. In conclusion, the study indicates that shortened gestational age and very low birth weight are predictors for later ages of emergence of the first primary tooth.

Centric slide in different Angle's classes of occlusion.

The purpose of this study was to test the possible differences in centric slide values between different Angle's classes of occlusion. The study included 98 participants divided into four groups: Angle's class I, Angle's class II, subdivision 1, Angle's class II, subdivision 2 and Angle's class III. All recordings were obtained using an ultrasound jaw tracking device with six degrees of freedom. The distance between the maximum intercuspation (reference position) and the centric occlusion was recorded at the condylar level. Anteroposterior, superoinferior and transversal distance of the centric slide were calculated for each participant, and the data were statistically analyzed (analysis of variance and Newman-Keuls post hoc test). No statistically significant difference was found in the anteroposterior and transversal distance of the centric slide between tested groups, while Angle's class II, subdivision 2 showed smaller vertical amount of the centric slide compared to Angle's class I and class II, subdivision 1. None of the 98 participants showed coincidence of centric occlusion and maximum intercuspation. Our results suggest that coincidence of the maximum intercuspation with the centric occlusion should not be expected. Smaller extent of the vertical distance of the centric slide could be morphological and a functional expression characteristic of the Angle's class II, subdivision 2.

Metric evaluation of partially displaced temporomandibular joint disc.

The objective was to determine the quantitative relationship between the condyle and disc position in the glenoid fossa between two different slices of the same temporomandibular joints (TMJs) with partial anterior disc displacement (DD). The study was conducted on 40 patients with DD of TMJs (mean age, 35.5 years). The clinical diagnosis of DD was confirmed by magnetic resonance imaging. Joints from the patient groups were analyzed according to the laterality and depending on disc displacement (a total of 80 joints). Comparison was made between two different slices of 9 joints with partial DD with reduction: partial DD was analyzed in the representative centrolateral or centromedial parasagittal slice of the TMJ (TMJ partial DD--slice DD). The contralateral slice of the same joint was without DD (TMJ partial DD--slice NDD). The analysis also included 34 healthy joints without DD (TMJ NDD) of the same patients. The position of the condyle and disc was calculated using the Kurita et al. method on the parasagittal view of the TMJ. A statistically significant difference was recorded for different slices of the same TMJs with partial DD (TMJ partial DD--slice DD and TMJ partial DD--slice NDD) (p < 0.01), but no difference was found in condyle positions depending on the existence of partial DD (p > 0.05). The compared values between slice TMJ partial DD--slice NDD with the group of TMJ NDD showed no significant difference in either disc position or condyle position (p > 0.05). There were differences of disc position in various slices of the same joint with visually confirmed partial DD. The dorsocranial condyle position could not indicate partial anterior DD.

Dental caries experience and tobacco use in 19-year-old Croatian army recruits.

The aim of this study is to investigate caries prevalence and smoking habit in the population of 19-year-old Croatian male recruits. Dental examination of 505 male recruits was conducted in 2001 in the military centre in Koprivnica. Caries status was described by the FS-T (Filled and Sound Teeth) index and DMFT (Decayed, Missing and Filled Teeth) index. Mean DMFT scores were 7.32 and FST 23.56. There was a significant statistical difference in comparison of smoking habits depending on the reason to visit the dentist (p = 0.001). The subjects who do not smoke tobacco have less decayed teeth (DT index with p < 0.001), and more teeth with fillings and/or sound teeth (FT with p = 0.005 and FST with p = 0.004). There is no statistically significant difference for the DMFT (p = 0.657) and MT (p = 0.703). In conclusion, it showed that FS-T is a more appropriate index for describing variation in the population with higher caries experience. In the population of Croatian recruits, there were an astonishing 58.6% of smokers.

Disc and condylar head position in the temporomandibular joint with and without disc displacement.

The purpose of this study was to evaluate the difference between disc and condyle position between temporomandibular joints (TMJs) without disc displacement (DD) in asymptomatic volunteers, and patients who have DD in contralateral joints, respectively unilateral DD. Secondly, there were two TMJ groups which consisted of measurements from patients' symptomatic DD and volunteers with asymptomatic DD. The study included 79 TMJs of 40 patients with unilateral DD. In the group of 25 asymptomatic volunteers, 20 volunteers were without DD bilaterally (40 joints), while five had DD in at least one TMJ. All subjects were examined clinically and DD was confirmed by magnetic resonance imaging. Left and right TMJs were analysed independently for each participant based on their DD status (symptomatic, asymptomatic, and without DD). All asymptomatic TMJs did not have any clinical signs of TMJ functional abnormalities. There was a significant statistical difference between disc position among TMJs without DD in asymptomatic volunteers and TMJs without DD in patients (p = 0.016). Moreover, no significant differences were found between condyle position in the same groups of joints (p = 0.706). There were no significant differences in the DD position (p = 0.918) or condyle position (p = 0.453) between the group with asymptomatic volunteers' joints and the group with symptomatic patients' joints. There was a significant difference between patient and volunteers' joints without DD: the disc was positioned more anteriorly in patients' joints without DD than in joints of asymptomatic volunteers without DD.

Pathophysiology of osteonecrosis of the jaw in patients treated with bisphosphonate.

Apart from the well-known mechanism of bisphosphonates' cellular effect, embryonic development and the specific features of alveolar bone homeostasis have been discussed. The unique ethiopathogenic mechanism which relates osteonecrosis of the jaw and bisphosphonates treatment has not been explained. The emphasis lies on the toxicological effects of bisphosphonates on the physiology of the alveolar bone and on the lasting effect of tooth extraction followed by an infection of the extraction wound and consequent progression into deeper layers of osseous tissue. Epithelial infection includes microbiological findings of Actinomyces species. The risk is pronounced in oncological patients treated with bisphosphonates intravenously in relatively large doses and during a longer period of time, especially with highly potent nitrogen-containing bisphosphonates pamidronate and zoledronate. This review of bisphosphonate-related osteonecrosis of the jaw stresses the significance of some other risk factors (corticosteroids, chemotherapy, tumour tissue etc.) of necrosis development--more precisely of osteomyelitis of the jaw if the microbiological component of the diseases has been taken into account, while the role of the bisphosphonates becomes minor. There is no gold standard for the treatment of jaw osteonecrosis; rather, palliative and minimally invasive treatment is applied, without subsequent oral surgical interventions. Since there is a significant risk of jaw osteonecrosis in oncological patients, the level of oral health is an important factor for the indication of intravenous bisphosphonates treatment.

Analysis of dental supportive structures in orthodontic therapy.

The purpose was to define the impact of orthodontic appliances on the density of the underlying dental bone tissue. Radiographic images of teeth were made in 27 study subjects before and twelve months after fixed orthodontic appliances were carried. The radiographs were digitalized and the levels of gray at sites where the greatest bone resorption was expected were transformed into optic density. In the standardization and comparison of values from the first and the second measurements the copper calibration wedge--a stepwedge--was used. Optic densities in the observed sites were compared with optic densities of the calibration wedge and expressed as their thickness equivalent. The study results showed no statistically significant difference in bone densities, indicating that the orthodontic therapy was properly planned and carried out and that excessive forces were not used in the applied correctional procedures.

Temporomandibular disorders and occlusion.

Occlusion has an important place within the multifactorial concept of the temporomandibular disorder (TMD) etiopathogenesis as well as in every form of dental treatment. The modern concept of treatment of these disorders differentiates initial and definitive forms of treatment. The aim of this paper is to analyze recent viewpoints on the role of occlusion in the etiopathogenesis and treatment ofTMDs. Masticatory muscles and temporomandibular joints are directly connected with occlusal relations and TMDs are traditionally linked with occlusal disorders. The initial occlusal treatment can be applied to all TMD patients, regardless of their having intact teeth with respect to physiological occlusal relations and in patients in need of orthodontic or prosthodontic treatment or an oral surgical procedure. On managing TMD patients, there are doubts about the indications for definitive treatment and whether there has been a possibility of treating a painful TMD by reversible treatment modalities, that is, by initial treatment. Other types of orofacial pain such as trigeminal neuralgia can be comorbid with TMDs but also result in unnecessary procedures on the teeth and prosthodontic work if they are not recognized. Although dental profession mainly recognizes the importance of occlusal treatment of TMD problems, their relationship is controversial because it is not strictly demonstrated in numerous scientific studies. Occlusion is not the dominant cause of TMD problems.

Osteoarthritic temporomandibular joint changes confirmed by magnetic resonance imaging.

Clinical and radiological findings were compared between the patients with osteoarthritis (OA) of temporomandibularjoint (TMJ) with or without disc displacement (DD), and asymptomatic volunteers. This study included 30 patients with OA of TMJs (mean age 52.6). All the patients were examined clinically by manual functional analysis and using magnetic resonance imaging. The inclusion criteria for patients comprised: pain referred to the TMJ and/or crepitation in the TMJ. A second group consisted of 20 asymptomatic dental school students (mean age 23.5). There is a statistically significant difference between degenerative changes of the condyle of TMJs with and without clinical signs of OA of patients (p=0.009). In 28% of osteoarthritic joints, flattening of condylar joint surfaces was observed and 17.4% of the joints were without clinical signs of OA. Osteophyte formations were found in 8% of asymptomatic and 25.7% of osteoarthritic patients' joints. There is a statistically significant difference between patients' TMJs with and without OA (p=0.0003): pronounced shape loss and severe sclerosation of the articular eminence were found in 12% of the joints without OA, and 42.9% of joints with OA. There is no difference between students' joints and patients' TMJs without OA (p=0.804). The most common imaging findings of osteoarthritic TMJs were sclerosis of the condyle and osteophyte formation.

Temporomandibular joint disorder in a patient with multiple sclerosis--review of literature with a clinical report.

Temporomandibular disorders are a form of musculoskeletal disorders, which reduce the function of stomatognathic system and they are related to some other diseases causing painful conditions and disorders of oral function. The aim of this paper is to describe a one year follow up clinical case of a female patient with comorbid multiple sclerosis and a relatively rare form of articular disc disorder. Primary clinical diagnostics encompassed manual methods of TMJ examination. Definite diagnosis included radiologic examination. Clinical hyperextensive condyle position was palpated bilaterally and subsequently confirmed by a functional panoramic radiograph of TMJ. The anterior displacement of disc with reduction was diagnosed by magnetic resonance and in the right joint there was a disc displacement upon excursive movement. From relevant literature, the relationship of a number of diseases that can be related to functional disorder of the orofacial system, such as multiple sclerosis, has been described from many aspects. Also, apart from the standard classification of one form of anterior displacement of the disc, made primarily by magnetic resonance, cases of disc displacement upon excursive mandibular movement can rarely be found in literature.

[Relationship between osteonecrosis of the jaw and bisphosphonate treatment]. / Povezanost osteonekroze celjusti i terapije bisfosfonatima.

Bisphosphonate treatment and its aetiopathogenic association with aseptic osteonecrosis of the jaw is one of the more prominent public health issues today. The aim of this review is to see into the mechanisms of bisphosphonate effects on bones described in literature (anti-osteoclastic activity, cytotoxicity, antiangiogenesis, genetic factors, and imbalance between osteoclasts and osteoblasts). Bisphosphonate treatment is the dominant cause of jaw necrosis. Epidemiological data show an exclusive incidence of osteonecrosis of the jaw in patients who took one or a combination of nitrogen-containing bisphosphonates. Risk factors vary by the bisphosphonate potency (particularly risky are the highly potent pamidronate and zoledronate, which are given intravenously), dosage, duration of treatment, and the illness. Jaw necrosis is most common in oncology patients, and only 5 % in patients with osteoporosis. From a dental-medical point of view, a good oral health is important because osteonecrosis often appears after a periodontal or oral surgical procedure.