Colour Stability of Composite- A Review.

Current innovations in restorative dentistry include nanofilled composite resinmaterials for direct and indirect restorations. Moreover, the advances in adhesivedentistry have provided autopolymerising, dual-polymerizing and lightpolymerizing resin-based adhesives for ceramic restoration bonding. In addition,resin cements have been combined with self-adhesive components for adhesiveprocedures. Composite failure has been a great challenge for dental clinician all overthe world , making it difficult for the dentist to satisfy patients. Major problems seeninclude polymerization, shrinkage and colour instability. There being no perfectmethod for this restorative material to overcome the problems, clinicians must keepin mind as to what material and technique should be used in a patient dependingupon the case. The success of composite restorations is due to their colour stabilityover time. Accurate shade matching of tooth coloured restoration with the adjacentdentition is essential not only at the time of fabrication but also for the lifetimedurability. Discolouration of composite resins can be caused by internal or externalfactors. Internally induced discolouration is permanent and is related to polymerquality, filler type, and amount, as well as the synergist added to the photo initiatorsystem. Alterationof matrix or filler components of resin composites andincomplete polymerization constitute intrinsic factors leading to discolouration. It isreported that saliva, food components, and beverages may affect the aesthetics andintegrity of dental composites. This is a factual truth for dental porcelain but incontradiction, colour instability in porcelain restoration is a common dilemmanowadays, especially when they are exposed to routinely consumable beverages.We have reviewed different factors responsible for colour stability of compositerestoration, and different s

Functions of Root Canal Sealers- A Review.

Endodontic therapy is a treatment for the diseased pulp of a tooth. It will result in the removal of infection and the preservation from further microbial invasion. The principle constituents of an endodontic filling are- a core material “gutta percha” and “endodontic sealers”. All the current obturating techniques make use of the sealer to augment the seal endodontic filling material. It fills the space between canals. Endodontic sealer fills the space between the material as well as root dentin. Different types of sealers are available (resin sealers, ZOE sealers, mineral trioxide aggregate sealer, bio-ceramic containing sealers, glass ionomer containing sealer, calcium hydroxide containing sealer). Root canal sealers have different functions- antibacterial, lubricant for core material, to increase radio-opacity of core or as a filling material. Different types of microorganisms as well as microbial products cause pulpal as well as peri-radicular diseases. Microorganisms persist in the canal due to poor irrigation. We wanted to evaluate the various functions of different endodontic sealers. The perfect apical seal obtained by use of sealers is one which is stable and non-irritating in nature. It should also give us a smoother seal. Biocompatibility of root canal sealer has importance as it is placed directly in contact with the living tissue. Response of dental tissue help in the final outcome of successful endodontic treatment. Bond strength between canal walls exhibit through micromechanical retention. It helps in preventing the dislodgement of filling material. It ultimately helps in maintenance of interface between filling material and sealers. Push out test is the process to assess bond strength among filling material and sealers. Endodontic sealer has sufficient amount of radiopacity so that it can be clearly visualised among material and adjacent anatomical structures.

Removal Techniques for Intracanal Medicament- A Review

This article reviews irrigation techniques for removal of intracanal medicament in endodontic practice. Microorganisms are the primary etiological factors for pulpal and periradicular diseases. So primary purpose is to completely eradicate microorganism from the root canal. It is done through chemo-mechanical preparation of the canal. Complete disinfection of the pulp space cannot be achieved with most sophisticated instrumentation techniques. Therefore use of inter appointment intracanal medicaments is mandatory. Removal of the medicament is mandatory, as its remnants may mechanically block the apical area of the root canal system. Also affects viscosity, working time, tubule penetration and adhesion of root canal sealers. Remnants of Ca(OH)2 in the canal react with unreacted eugenol present in ZOE based sealer to form calcium eugenolate. Today’s irrigation armamentarium presents a diverse variety of tools and techniques , that can assist the practitioner in reducing bacteria, debris, intracanal medicament within the canal system. Conventional syringe irrigation is a routinely practiced method for removal of medicament. It consists of delivering the irrigant in the canal passively or by agitation. Rotary brush does not actually render irrigating solution for removal of medicament. This acts like auxiliaries during removal of medicament from canal or for increased movement of irrigating solution. Ultrasonic irrigation is done with or without simultaneous ultrasonic instrumentation. EndoVac is negative pressure irrigation, which can be used as an alternative method that helps in safe removal of medicament in apical thirds. RinsEndo is also based on pressure alteration technology like EndoVac. Sonically driven system safely acti­vates various intracanal reagents and vigorously produces the hydrodynamic phenomenon as it includes EndoActivator and Vibringe. Laser activated irrigation is more effective for cleaning of root canal. Er:YAG is most commonly used laser in endodontics. Therefore, the aim of this article is to highlight the irrigation techniques used for removal of the intracanal medicament in endodontic practice.

Evaluation of tongue/mandible volume ratio in children with obstructive sleep apnea

ABSTRACT Objective: The present study was an attempt to investigate tongue/mandible volume ratio in children, using volumetric magnetic resonance imaging (MRI) for early screening and to aid in treatment planning. Methods: Volumetric evaluation of tongue volume/mandible volume ratio (TV/MV ratio) in children with obstructive sleep apnea (OSA) using MRI was carried out retrospectively on available DICOM MR images of children in the age group of 10-14 years. MRI image records of patients diagnosed with OSA were obtained from interventional radiology department records, at Sharad Pawar Dental College and Hospital (Datta Meghe Institute of Medical Sciences, Nagpur/India). The age, gender, height and weight of the subjects were retrieved from patient database and registered. For the control group, available MRI images of healthy subjects without OSA were retrieved. Body mass index (BMI) was also calculated using the height and the weight present in the records. Measurements from MR images were made using DICOM image processing software. Soft tissue and bony structure segmentation was performed by manual tracing. The tongue volume and mandible volume were directly computed using the software. The tongue volume/mandible volume ratio (TV/MV) was generated using the above values and expressed as a percentage for both groups. Results: The difference between OSA group and control group with respect to TV/MV ratio was found to be highly significant at 0.05 level of significance. There was no significant correlation between BMI and TV/MV ratio in OSA group (p= 0.451) as well as in control group (p= 0.094). Conclusion: TV/MV ratio may be an appropriate variable to evaluate the risk of OSA, representing the balance between skeletal morphology and soft tissue morphology in craniofacial complex.

Resumo Objetivo: o presente estudo foi uma tentativa de investigar a relação volumétrica língua/mandíbula em crianças, usando imagens de ressonância magnética (IRM), para triagem inicial e como meio auxiliar no plano de tratamento. Métodos: a avaliação da relação volume da língua/volume da mandíbula (relação VL/VM) em crianças com apneia obstrutiva do sono (AOS) utilizando IRM foi realizada retrospectivamente em imagens de RM em formato DICOM disponíveis de crianças na faixa etária de 10 a 14 anos. As documentações com IRM de pacientes com diagnóstico de AOS foram obtidas nos arquivos do departamento de radiologia da Sharad Pawar Dental College and Hospital (Datta Meghe Institute of Medical Sciences, Nagpur/Índia). A idade, o sexo, altura e peso dos indivíduos foram obtidos a partir dos registros dos pacientes. Para o grupo controle, foram selecionadas imagens de RM disponíveis de indivíduos saudáveis sem AOS. O índice de massa corporal (IMC) também foi calculado a partir da altura e do peso constantes nos registros. As medições nas imagens de RM foram feitas usando um software de processamento de imagens DICOM. A segmentação entre tecidos moles e estrutura óssea foi realizada por delineamento manual. O volume da língua e o volume da mandíbula foram calculados diretamente com o software. A relação volume da língua/volume da mandíbula (VL/VM) foi calculada usando os valores acima e expressa em porcentagens, para ambos os grupos. Resultados: a diferença entre o grupo com AOS e o grupo controle, quanto à relação VL/VM, foi altamente significativa ao nível de significância de 0,05. Não houve, porém, correlação significativa entre o IMC e a relação VL/VM, nem no grupo AOS (p= 0,451), nem no grupo controle (p= 0,094). Conclusão: a relação VL/VM pode ser uma variável apropriada para se avaliar o risco de AOS, representando o equilíbrio entre a morfologia esquelética e a morfologia dos tecidos moles no complexo craniofacial.