Anatomy and Embryology of the Mouth and Dentition
John C Watkinson, Raymond W Clarke, Terry M Jones, Vinidh Paleri, Nicholas White, Tim Woolford in Head & Neck Surgery Plastic Surgery, 2018
There are two generations of teeth: the deciduous (primary) dentition and the permanent (secondary) dentition. In the complete deciduous dentition there are 20 teeth—five in each jaw quadrant. In the complete permanent dentition there are 32 teeth—eight in each jaw quadrant. In both dentitions, there are three basic tooth forms: incisiform, caniniform and molariform. Incisiform teeth (incisors) are cutting teeth, having thin, blade-like crowns. Caniniform teeth (canines) are piercing or tearing teeth, having a single, stout, pointed, cone-shaped crown. Molariform teeth (molars and premolars) are grinding teeth possessing a number of cusps separated by fissures. Premolars are bicuspid teeth that are peculiar to the permanent dentition and replace the deciduous molars.
The Classification of Odontogenic Cysts
Roger M. Browne in Investigative Pathology of the Odontogenic Cysts, 2019
Most previous studies have combined the data for radicular and residual cysts and so there is relatively little information on the age and site distribution of these lesions. This is surprising because in a recent study residual cysts were found to comprise some 10% of odontogenic cysts.43 This study found a predominance in the mandibular premolar region, although they can occur in any part of the jaws. Although radicular cysts are more common in the anterior maxilla, the demand to retain teeth in this part of the jaw for aesthetic reasons probably explains the relatively low incidence of residual cysts. There is evidence too that most residual cysts become progressively smaller in size with age43 and even resolve completely.44
Tooth extraction
John Dudley Langdon, Mohan Francis Patel, Robert Andrew Ord, Peter Brennan in Operative Oral and Maxillofacial Surgery, 2017
In recent years, an increased appreciation of the benefits of preserving both bone and soft tissue at extraction sites where implant placement is planned has resulted in a greater general awareness of the benefits of optimizing alveolar and mucosal contour for all patients following dental extraction. Therefore, there has been shift away from the traditional surgical exodontia of multi-rooted teeth involving mucoperiosteal flaps and buccal bone removal towards a more conservative approach. When there is resistance to a forceps extraction (often attributable to unfavourable root morphology) rather than progressing to a conventional transalveolar approach, the sectioning or surgical division of the tooth will usually facilitate its removal without the need to raise a flap. This technique can be used to extract maxillary and mandibular molars or multi-rooted premolar teeth. Although the outcome is not as predictable as when a flap is raised, in experienced hands this technique may, however, offer the benefits of tissue preservation.
Morphological variations and prevalence of aberrant traits of primary molars
Published in Annals of Human Biology, 2021
P. Sujitha, R. Bhavyaa, M. S Muthu, M. Kirthiga
The parastyle is a paramolar cusp of Bolk that occurs on the mesiobuccal surface of upper molars (Turner et al. 1991). Although the literature pertaining to this trait is negligible, it is said to be predominant in deciduous molars (Kustaloglu 1962). In the present study, the results yielded a prevalence rate of 0.51% in primary maxillary second molars and 3.48% in primary maxillary first molars. Studies conducted among southwestern and northwestern Indians (Kustaloglu 1962) gave a prevalence of 5.2% and 4.7%, respectively, in primary maxillary second molars. The prevalence found in the present study was comparatively less in primary maxillary second molars. However, the prevalence of the parastyle was higher in primary maxillary first molars. The literature suggests primary maxillary first molars to be the “premolar section” of the primary dentition and to resemble certain features of premolars (Nelson and Ash 2012). The literature also suggests that this trait occurs more in premolars (Kustaloglu 1962), which can be the reason for its higher prevalence in primary maxillary first molars.
Effectiveness and safety of Bifidobacterium in preventing dental caries: a systematic review and meta-analysis
Published in Acta Odontologica Scandinavica, 2021
Siyuan Hao, Jiahe Wang, Yan Wang
We made a qualitative description for the infeasibility of implementing a meta-analysis. Totally, two studies compared Streptococcus mutans counts in dental plaque after the intervention [22,29]. Pinto et al. conducted a cross-design trial on 26 subjects wearing fixed orthodontic appliances with an average age of 15 years [22]. The intervention lasted for two weeks with a four-week interval of elution. Dental plaque samples were then taken around the orthodontic appliances of all the subjects’ premolars and canine teeth. The results showed no significant decrease in Streptococcus mutans counts in the dental plaque in the probiotic group compared with that before the intervention. Besides, the difference was not statistically significant compared with that of the control group. Similarly, Caglar et al. did not report a statistically significant difference in Streptococcus mutans counts in the dental plaque after administering placebo or Bifidobacterium-containing yogurt to 52 subjects aged 8‒10 in a cross-designed trial [29].
Assessment of antibacterial activity of 2.5% NaOCl, chitosan nano-particles against Enterococcus faecalis contaminating root canals with and without diode laser irradiation: an in vitro study
Published in Acta Odontologica Scandinavica, 2019
Nehal Nabil Roshdy, Engy M. Kataia, Neveen A. Helmy
This study was conducted on 60 single-rooted human premolars. The teeth were radiographically confirmed to have a single canal and were decoronated to obtain standardized lengths of 15 mm using a diamond disc. The canal patency was checked by #10 K-file (Mani, Japan) and the working length was considered 1 mm short of the root length (14 mm). Root canals were prepared using ProTaper rotary instruments (Maillefer-Dentsply, Baillagues, Switzerland) till size F4. In between the rotary files, canals were rinsed with 2 ml of 2.5% NaOCl (Clorox, Cairo, Egypt). After completion of instrumentation, the canals were rinsed with 1ml of 17% EDTA, 5 ml saline and 1 ml of NaOCl, respectively, for 3 min each to remove the smear layer. Then, all the canals were rinsed with 5 ml Saline as a final flush. The apical foramen was sealed with self-cure glass ionomer cement (Tokyo, Japan) and the root surfaces were covered with two layers of nail varnish. Each sample was transferred to a 2-ml microtube and autoclaved at 121 °C under a pressure of 15 psi for 30 min.
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