The marginal-ridge rest seat. (17/398)

Natural canine crowns are preferred as abutments for removable partial dentures because of their root morphology and bony support. However, preparing the rest seat on the lingual surface of a mandibular canine risks perforating the enamel. An alternative rest-seat preparation, on the marginal ridge of the canine crown, conserves tooth structure and provides a rest seat of adequate length and depth to ensure support for a cast framework. To illustrate why this little-discussed rest-seat preparation has endured locally, the rationale and preparation of the marginal-ridge rest seat is discussed from both historical and clinical perspectives.  (+info)

'Killer' canines: the morbidity and mortality of ebino in northern Uganda. (18/398)

In northern Uganda, unerupted primary canine teeth are commonly extracted because they are believed to cause diarrhoea, vomiting, and fever. This practice, known as ebino, is performed under very crude conditions often using unclean tools. To evaluate the morbidity and mortality of complications related to ebino, we retrospectively analysed discharge records from the paediatric ward of Lacor Hospital, Gulu. In the period 1992-98, ebino-related complications, mainly sepsis and anaemia, were among the leading causes of admission (n = 740) and hospital death (n = 156, case fatality rate = 21.1%, proportional mortality rate = 3.3%). Discouraging the adoption of deeply rooted traditional practices that are potentially hazardous to health should be a public health priority in northern Uganda. This could be done by educating not only the general public, but also traditional healers and community and religious leaders, who could convey the knowledge to their people.  (+info)

A review of impacted permanent maxillary cuspids--diagnosis and prevention. (19/398)

As impacted permanent maxillary cuspids occur in 1-2% of the population, the general dentist should know the signs and symptoms of this condition and the interceptive treatment. Features of buccal or palatal cuspid impaction include lack of canine bulges in the buccal sulcus indicating a lingual eruption path and possible impaction; lack of symmetry between the exfoliation and eruption of cuspids that may indicate palatal or lingual impaction; and abnormal mesiodistal location and angulation of the developing maxillary permanent cuspids on radiographs. Diagnosis of impacted cuspid teeth at age 8-10 years can significantly reduce serious ramifications, including surgical exposure and orthodontic alignment as well as root resorption of the lateral incisors. In specific cases, extraction of the primary maxillary cuspids can prevent impaction of the permanent maxillary cuspids and additional sequelae.  (+info)

A radiographic comparison of apical root resorption after orthodontic treatment with a standard edgewise and a straight-wire edgewise technique. (20/398)

The purpose of this study was to compare the severity of apical root resorption occurring in patients treated with a standard edgewise and a straight-wire edgewise technique, and to assess the influence of known risk factors on root resorption incident to orthodontic treatment. The sample consisted of 80 patients with Angle Class II division 1 malocclusions, treated with extraction of at least two maxillary first premolars. Variables recorded for each patient included gender, age, ANB angle, overjet, overbite, trauma, habits, invagination, agenesis, tooth shedding, treatment duration, use of Class II elastics, body-build, general factors, impacted canines, and root form deviation. Forty patients were treated with a standard edgewise and 40 with a straight-wire edgewise technique, both with 0.018-inch slot brackets. Crown and root lengths of the maxillary incisors were measured on pre- and post-treatment periapical radiographs corrected for image distortion. Percentage of root shortening and root length loss in millimetres were then calculated. There was significantly more apical root resorption (P < 0.05) of both central incisors in the standard than in the straight-wire edgewise group. No significant difference was found for the lateral incisors. Root shortening of the lateral incisors was significantly associated with age, agenesis, duration of contraction period (distalization of incisors), and invagination, while root shortening of the central incisors was related to treatment group and trauma.  (+info)

The use of the Index of Orthodontic Treatment need (IOTN) in a school population and referred population. (21/398)

The aim of this study is to assess the need for orthodontic treatment in a Turkish school population and a group of population referred for orthodontic treatment. The study groups were 250 school children, 11-14 years of age, and 250 patients, 11-14 years of age, referred to the department of orthodontics. The Index of Orthodontic Treatment Need (IOTN) was used by two examiner in order to estimate the treatment need. The differences between the IOTN values for the boys and girls were also not statistically significant in both groups. When the dental health component of IOTN is considered, 38.8 per cent of Turkish school population showed great need treatment, 24.0 per cent moderate need treatment and slight or no need was 37.2 per cent. On the other hand, the referred population represented an 83.2 per cent great need treatment, 12.0 per cent moderate need treatment, 4.8 per cent no need treatment according to the DHC. The AC of IOTN in school population resulted in 4.8 per cent great need, 4.8 per cent moderate need, 90.4 per cent no need. These percentage were 36.8 per cent great need, 17.6 per cent moderate need, 45.2 per cent no need in referred population. Grade 8 was 28.8 per cent out of the 36.8 per cent great need percentage in referred population. Therefore, it can be concluded that the ectopic canines were the driving factor for the referred population.  (+info)

An ex vivo study to investigate bond strengths of different tooth types. (22/398)

This study aimed to identify the presence and pattern of differences in ex vivo shear bond strength between tooth types when bonding orthodontic brackets using Right-On, and took the form of a prospective laboratory study of bond strength on different tooth types, at the Newcastle University Dental School Materials Science Laboratory, 1997-1999. Ex vivo bond strength testing was undertaken using the technique described by Fox et al. (BJO 18, 125-130, 1991) on a total of 120 extracted incisor, canine, and premolar teeth of each dental arch. Analysis was by one-way ANOVA with Tukey's pairwise comparisons, and by Weibull Analysis. Shear stress to failure (measured in MPa) was recorded on Instron 5567 universal testing machine. Significant differences in mean bond strength existed between different tooth-type series. Canine (upper 12.3, lower 12.1) and premolar (upper 11.9, lower 10.9) teeth exhibited higher strengths than incisors (upper 6.9, lower 9.0). The results of this study confirm that ex vivo bond strength is not uniform across all teeth.  (+info)

The radiographic localization of impacted maxillary canines: a comparison of methods. (23/398)

This study compared two different radiographic techniques for localization of impacted maxillary canines: vertical parallax (from a panoramic and a maxillary anterior occlusal radiograph) and magnification (from a single panoramic radiograph). The radiographs and the information regarding the impacted canines were obtained retrospectively from records of patients treated in the Day Stay Unit of the Eastman Dental Hospital. The two different radiographic techniques were tested blind and compared for localization of the impacted canine by six examiners. The 'gold standard' used for the radiographic comparisons was the true position of the canine as recorded at operation. The results showed a wide variation between the six examiners in the prediction of the canine position with the two different techniques. Localization with vertical parallax was more successful overall than with magnification, although the difference failed to reach significance. Seventy-six per cent of the impacted canines could be successfully located with vertical parallax and 66 per cent with magnification. Further analysis showed that, while almost 90 per cent of the palatally impacted canines could be correctly detected with both techniques, less than half of the buccal canines could be detected with parallax and only one in 10 buccal canines could be detected with magnification. If a canine is suspected to be buccally placed from its appearance on a panoramic film and cannot be palpated, further views are justified.  (+info)

Ridge augmentation using mandibular tori. (24/398)

A 19-year-old female was referred by her dental practitioner for the restoration of missing maxillary lateral incisors and canines. Ridge augmentation was required. This was undertaken using mandibular tori as the sites for harvesting bone. The grafting was successful and the spaces were subsequently restored using resin-bonded bridgework. The case reports that mandibular tori provide a local and convenient source of bone for ridge augmentation procedures.  (+info)