Prosthetic posterior teeth with cusps may improve patient satisfaction with complete dentures

DATA SOURCES: The Cochrane Oral Health Group Trials Register, Cochrane Central Register of Controlled Trials, Medline, OLDMedline, Embase, Zetoc (Zetoc provides access to the British Library's electronic table of contents of approx. 20,000 current journals and 16,000 conference proceedings published per year. The database covers 1993 to date and is updated daily. It includes an e-mail alert service to enable you to keep up-to-date with relevant new articles and papers), System for Information on Grey Literature in Europe (SIGLE) (SIGLE is a bibliographic database covering European non-conventional (or 'grey') literature in the fields of pure and applied science and technology, economics, social sciences and humanities), and the Science Citation Index were used to source studies. Reference lists of identified, relevant trials and review articles were scanned. Unpublished data were sought through personal contact with experts in the field. There was no language restriction. STUDY SELECTION: Randomised controlled trials (RCT) or quasi-RCT were selected that recruited edentulous adults and compared complete dentures with different occlusal schemes, with regard to patient satisfaction and masticatory function. DATA EXTRACTION AND SYNTHESIS: The quality assessment of included trials was undertaken independently and in duplicate by two reviewers. Data were also extracted by two reviewers independently. Disagreements were discussed and a third reviewer consulted as necessary. Authors were contacted for clarification or missing information. Data were excluded until further clarification if agreement could not be reached. RESULTS: Thirteen trials were thought to be potentially relevant. Ten of these studies were subsequently excluded following further analysis. Two trials require further information from the author before being considered eligible for inclusion. Only one crossover trial (n=30), which compared lingualised teeth and zero-degree teeth, fully met the review's inclusion criteria. Twenty patients preferred the lingualised denture, five the zero-degree denture and five patients had no preference. There was a statistically significant difference in favour of the lingualised denture with an odds ratio of 10.00 (95% confidence interval, 2.04-48.96). CONCLUSIONS: There is weak evidence that it may be advantageous for dentists who provide a complete denture service to prescribe prosthetic posterior teeth with cusps, rather than cuspless teeth, to improve patient satisfaction. This conclusion may only be made tentatively until further, well-conducted trials are undertaken that compare different occlusal schemes for complete dentures.     

影响纵折后牙保守治疗预后的因素

后牙纵折是临床常见的非龋性牙体组织破坏性疾病,发病率较高,常作拔牙处理。随着人们生活水平的不断提高,人们对牙齿保留越来越重视。国内外许多学者对纵折后牙的保守治疗做了大量的研究。本文就影响纵折后牙保守治疗预后的因素及其机制作一综述。     

纵折后牙保存治疗的临床观察

目的:探讨后牙纵折的保存治疗方法。方法:用结扎外固定方法,对68个纵折后牙行根管治疗术,树脂充填,全冠修复。结果:11个患牙保存失败拔除外,其余疗效满意,保存成功。结论:后牙纵折后及时诊断并经过完善治疗,可以保存患牙而避免拔牙。     

后牙纵折保存治疗的临床评价

目的保存纵折后牙,探讨如何提高保存治疗成功率。方法采用Super-bond C＆B粘结系统对39例完全纵折后牙进行粘结固定后全冠修复。结果 39例纵折后牙修复治疗6个月复查失败3例,修复成功与修复失败分布有明显差别（P=0.028〈0.05）,12个月随访另有4例失败但修复成功与修复失败分布有明显差别（P=0.020〈0.05）。12个月修复成功纵折后牙保存率为87.5%。结论 Super-bond C＆B粘结剂口外粘结纵折牙后行全冠修复,对纵折后牙保存治疗具有较为满意的疗效。     

115例纵折后牙临床分析及疗效观察

目的对后牙完全性纵折进行临床分析,对治疗效果进行评价。方法对115颗后牙完全性折裂的一般情况进行分析;根据不同的折裂情况进行不同的处理并采用冠修复,随访6个月～5年,评价治疗效果。结果完全性折裂以后牙常见,发生率上颌高于下颌,又以第一磨牙最为多见;115颗纵折后牙有85颗（73．91％）做过牙髓治疗,其中76颗做过完善的根管治疗;30颗未经过牙髓治疗。5年成功率为77．78％。结论后牙的纵折,特别是折裂前已做过完善根管治疗的后牙,及时就诊、合理的结扎固定以及符合生理要求的全冠修复是治疗成功的关键。     

The fracture behaviour of human and pig molar cusps

Masticatory efficiency depends upon the ability of the molar cusps to apply concentrated bite forces to food particles and simultaneously to withstand the dental stresses that may cause enamel fracture. This study investigated how low-crowned molar cusps in omnivorous mammals, specifically humans, Homo sapiens, and pigs, Sus scrofa, resist fracture under compressive load. A uniaxial compressive load was applied to individual molar cusps with a materials testing machine. The progressive loading and deformation of the cusps were recorded for interrupted and continuous tests. In interrupted tests, the appearance of progressive cusp fracture was recorded. Stiffness and fracture stresses were calculated from continuous test results. Pig cusps responded to both interrupted and continuous loads with greater deformation; progressive crumbling of the cusp tip resulted in new occlusal contacts on enamel lophs. Conversely, human cusps showed minimal breakage before failure. Continuous compressive tests demonstrated the greater stiffness of human cusps, as well as the capacity to sustain higher cusp tip stresses. The greater stiffness and high fracture resistance of human cusps may be attributed to the thickness of enamel. Test results reflected fundamentally different means of crown stress management that correspond with phylogenetic differences in masticatory function.     

Effects of composite restorations on resistance to cuspal fracture in posterior teeth

A clinically acceptable MOD cavity preparation was used instead of a jig-mounted slot preparation in this investigation. Each preparation was proportional to the tooth dimension. The design of the testing instrument ensured that forces applied to the specimens were applied to tooth structure and not to the restorative material. Prepared unrestored teeth were weaker than restored teeth. No significant difference was noted in fracture resistance between teeth restored with amalgam and with composite resin. The method used in this study is replicable, allowing the possibility of comparison studies by using identical procedures. Future research will focus on issues of polymerization method and modulus of elasticity and their effects on fracture resistance of remaining tooth structure.     

Bilateral talon cusps in primary teeth: clinical significance and treatment

Bilateral primary talon cusps are uncommon. This case report documents two new cases of bilateral talon cusps in the primary dentition. The clinical features, radiographic characteristics, and differential diagnosis of this developmental anomaly are described. The terminology, epidemiological data, potential complications, and various modes of treatment are reviewed and discussed. A new classification system was proposed. The dental anomalies of these two cases were not associated with any other somatic or dental abnormality. The general prognosis of this abnormality is satisfactorily good. However, the dentist needs to have early recognition of this anomaly in order to provide timely treatment in order to prevent potential complications.     

An unusual case of double teeth with facial and lingual talon cusps

Double teeth and talon cusps are rare developmental dental anomalies affecting both primary and permanent dentitions. Talon cusps normally occur on the palatal surface of permanent maxillary incisors, although double teeth are more common in the primary anterior dentition. This paper describes a rare case of fusion of the mandibular permanent incisors with labial and lingual talon cusps. An understanding of these dental anomalies and their associated problems are important to provide prophylactic measures, thereby preventing or minimizing possible complications.     

Composite core-supported stainless steel crowns enhance fracture resistance of severely damaged primary posterior teeth

BackgroundExtraction of severely damaged primary teeth has been the common treatment for early childhood caries. The early loss of primary teeth results in poor oral and general health in children.ObjectivesTo assess fracture resistance of severely damaged primary molars restored with intracoronal core with and without stainless steel crown (SSC).Materials and methodsEighty extracted primary molars were divided into 4 groups: Group 1 MOD cavity; Group 2 MOLi cavity; Group 3 MODLi and Group 4 MODBLi. Pulpectomy and core build-up with and without SSC placement were carried out and subjected to fracture resistance testing to examine the load to fracture and type of fracture.ResultsFracture loads of 870–950 N were observed in the fabrication of intracoronal composite core in teeth with 1–2 remaining tooth walls whereas higher fracture load of teeth with extensive loss of all the surrounding wall following intracoronal composite core build-up was 1270 N. Following SSC placement, all groups had higher fracture load, with Group 4 being resisted to the highest force at 5500 N. Without SSC, Group 1 and Group 2 appeared to be restorable whereas Group 3 and Group 4 were non-restorable when fractured. Following SSC placement, all groups showed non-restorable fracture at the root furcation.ConclusionsCombined intracoronal core and SSC significantly strengthen the restored severely damaged primary molars with severe loss of coronal tooth structures. This proposed restoration method provided resistance to occlusal load that is much higher than the physiologic chewing force in children.     

Fracture durability of restored functional cusps on maxillary nonvital premolar teeth.

Palatal cusps of nonvital maxillary premolar teeth were restored with a coronal-radicular restoration of posterior composite resin (Occlusin), amalgam (Tytin), or cermet (Chelon-Silver). Mean fracture strength values were: 370 lb for intact premolar teeth, 266 lb for amalgam, 215 lb for posterior composite resin, and 132 lb for cermet. From this in vitro study it can be suggested that for selected endodontically treated maxillary premolar teeth, the dentist can use acid-etch-retained posterior composite resin or pin-retained high copper amalgam material for a definitive coronal-radicular restoration. The use of cermet for this purpose is contraindicated.     

Prevalence of talon cusps in Jordanian permanent teeth: a radiographic study

Background  

The aim of the study is to investigate the prevalence of talon cusps in a sample of Jordanians dental patients and their distribution among different types of teeth.