Removal of unerupted teeth
John Dudley Langdon, Mohan Francis Patel, Robert Andrew Ord, Peter Brennan in Operative Oral and Maxillofacial Surgery, 2017
Maxillary second premolar teeth may fail to erupt as a consequence of crowding or space loss following the early extraction of primary teeth. These almost always occupy a palatal position, often becoming ‘trapped’ above the contact point between the first premolar and molar which have become approximated. A palatal flap created by a gingival sulcus incision extended to include at least two teeth either side of the unerupted premolar is used to provide access for the extraction. Once the flap is raised, the premolar is often accessible for the use of a luxator to elevate it. If this is not the case, bone removal to expose the crown usually facilitates its delivery. If resistance to movement is encountered or the position of adjacent teeth makes them vulnerable to becoming mobilized when reasonable force is applied, the crown of the premolar should be sectioned from the root to complete the extraction without complication (Figure 6.7).
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
Behind the canines are two premolars, each with a buccal and lingual cusp (hence the term bicuspid). The occlusal surfaces of the maxillary premolars are oval (the long axis is buccopalatal) with a mesiodistal fissure separating the two cusps. The maxillary first premolar usually has two roots (one buccal, one palatal). The maxillary second premolar usually has one root. The occlusal surfaces of the mandibular premolars are more circular or squarer than those of the uppers. The buccal cusp of the mandibular first premolar towers above the very much reduced lingual cusp. In the mandibular second premolar, the lingual cusp is more substantial compared with the first, and frequently presents as two cusps. Each lower premolar tooth generally has one root.
Effect of ceramic material type on the fracture load of inlay-retained and full-coverage fixed dental prostheses
Published in Biomaterial Investigations in Dentistry, 2020
Hamid Kermanshah, Fariba Motevasselian, Saeedeh Alavi Kakhaki, Mutlu Özcan
In this study, the fracture load of 3-unit inlay-retained fixed partial dentures made from either monolithic zirconia or zirconia reinforced lithium silicate were tested and compared with that of 3-unit full-coverage fixed partial dentures made from monolithic zirconia. The inlay-retained monolithic zirconia FPDs received two types of surface treatments. All FPDs were designed to restore maxillary second premolar. Inlay-retained monolithic zirconia FPDs showed fracture load which were not statistically different from 3-unit full-coverage monolithic zirconia FPDs, regardless of type of surface treatment. Inlay-retained FPDs made from zirconia reinforced lithium silicate failed at a significantly lower load than the other types of FPDs. Thus, the first null hypothesis about the non-significant effect of retainer design on fracture load was accepted. However, the second null hypothesis that ceramic type is inconsequential on fracture load was rejected.
Effects of low-intensity laser therapy on the stability of orthodontic mini-implants: a randomised controlled clinical trial
Published in Journal of Orthodontics, 2018
Ahmed Mohamed Abohabib, Mona Mohamed Fayed, Amr H. Labib
In the current study, adult patients requiring therapeutic extraction of maxillary first premolars and subsequent maxillary canine retraction with fixed appliances were chosen to provide a sufficient period of tooth movement in which mini-implant stability could be investigated. A split-mouth design was utilised for the current study to exclude individual variabilities from the estimates of treatment effect (Lesaffre et al. 2009) and prospective randomisation was used to reduce bias (Suresh 2011). The joint head type of the AbsoAnchor orthodontic mini-implant was selected as it has internal threads that can receive the Osstell SmartPeg. All mini-implants were placed using a torque driver to control and standardise the placing torque. The chosen torque of 7 Ncm as maximum was selected according to the manufacturer instruction to be below the torque-resisting force of AbsoAnchor mini-implants to minimise the risk of fracture. The selected mini-implants had a diameter of 1.5 mm and a length of 8 mm. This was based on clinical recommendations to minimise the risk of root proximity or contact that might contribute to failure during treatment (Kuroda et al. 2007). The placement site of the mini-implants, between the maxillary second premolar and first molar buccally was also selected based on clinical recommendations which advocate this site as a bone stock for safe mini-implants implantation in the maxillary arch (Schnelle et al. 2004). Similarly, the highest mesio-distal buccal-palatal distances have been reported between the second premolar and first molar (Fayed et al. 2010). Maximum success rates are not only due to easy access but also due to a low frequency of root proximity (Kuroda et al. 2007).
Related Knowledge Centers
- Deciduous Teeth
- Maxillary First Molar
- Maxillary First Premolar
- Mouth
- Premolar
- Tooth
- Face
- Chewing
- Cusp
- Permanent Teeth