Effect of the adhesive application mode and fiber post translucency on the push-out bond strength to dentin

This study evaluated the effect of the adhesive application mode and fiber post translucency on the push-out bond strength to dentin. Bovine roots were endodontically treated, and 10 roots were used for each adhesive application mode: PB (Prime&Bond 2.1), PB + SC (Self-cure activator), PB + SBM (Scotchbond Multi-purpose adhesive system), BB (Brush&Bond), BB + CAT (chemical catalyst), and BB + SBM. The translucent Light-Post and Aestheti-Post were cemented. The roots/cemented posts were transversally sectioned to originate three thirds (cervical, middle, and apical). The push-out test was performed, and the failure mode of fractured specimens was analyzed. There was no difference between the fiber posts. For PB and BB, the use of hydrophobic adhesive resin SBM increased post bond strength. The use of SC and CAT catalyst did not affect the push-out bond strength values. The apical third presented the lowest bond strengths.     

An atypical lingual lesion resulting from the unhealthy habit of sucking the lower lip: clinical case study

Unhealthy oral habits may be involved in the etiology of a malocclusion, since they may affect development of the orofacial region. There is little information on the habit of sucking the lower lip, to which practitioners attribute less clinical consequences. However, lower lip sucking is a harmful habit which appears frequently in children, especially during situations requiring increased attention and mental concentration. In patients presenting lower lip sucking, strong contractions of the lower lip's orbicular's muscle and the mentalis muscle, associated with hypertonicity of the upper lip caused by sucking, has to be balanced by lingual thrusting during the act of deglutition. A case is presented in which failure to identify the habit of lower lip sucking led to an atypical lesion on the tongue, caused by the tongue's impaction against the orthodontic appliance prescribed to correct a malocclusion. The recognition and elimination of an unhealthy habit is of great importance in diagnosis and the establishment of a treatment plan, so that undesirable complications can be avoided.     

Congenital isolated midline sinus of the upper lip: clinical and embryological approaches.

OBJECTIVES: Congenital sinuses or fistulas of the lip are uncommon malformations, yet true medial upper-lip fistulas (MULFs) are extremely rare. We present a new case of congenital upper-lip fistula located in the midline of the philtrum of an 8-month-old girl. INTERVENTION: Complete surgical removal was performed with a combined extra- and intraoral approach. Histological examination revealed that the fistula was lined by squamous epithelium with sebaceous and mucous glands and hair follicles. RESULTS: Several embryological hypotheses have been proposed concerning these anomalies. This article reexamines and discusses major embryological theories on pathogenesis of sinuses or fistulas of the upper lip. We propose that early ectodermal inclusion events may occur in the medial fusion area during formation of the intermaxillary process. This embryological approach is highly concordant with our recent hypothesis on nasal dermoid sinus cysts (NDSCs) pathogenesis, in which we proposed an embryological hypothesis with early ectodermal inclusion phenomenon in the midline suture area to explain NDSCs pathogenesis. CONCLUSIONS: Common early ectodermal inclusion phenomena could be involved in both NDSCs and MULFs pathogenesis.     

Panoramic radiograph as a method for detecting calcified atheroma plaques. Review of literature

Cerebrovascular accident (CVA) is the third cause of death in industrialized countries, following cardiovascular disease and cancer. It is therefore a significant public health issue, not only due to its high incidence, but also to the high costs involved in the physical and psychological rehabilitation of these patients. Dental Practitioners, as health care providers, ought to play their part in this issue and contribute, within their means, to the early detection of patients at risk of having a CVA. Since the eighties, different authors have described the possibility of detecting calcified atheroma plaques located at carotid artery bifurcation through panoramic radiograph. In this way, the Dental Practitioner s possibilities in this field have been extended. However, this new use of panoramic radiograph must overcome certain obstacles before it is implemented as a new screening method for patients at risk of having a CVA. Amongst these, we would have, on the one hand, the assessment of the real clinical significance, as regards prognosis, of atheroma plaque calcification as well as its usefulness as a factor for predicting the appearance of CVA symptoms and, on the other hand, the possibility of making a correct differential diagnosis regarding other calcified structures that may appear on panoramic radiograph.     

Mechanical properties of visible light-cured resins reinforced with hydroxyapatite for dental restoration.

OBJECTIVES: The purpose of this study was to measure and analyze the mechanical properties of several composite materials designed for dental restoration. METHODS: The materials were composed of a visible light-curing monomer mixture (either Bis-GMA+TEGDMA or Bis-GMA+HEMA) as a matrix and hydroxyapatite (either microscopic or nanoscopic particles) as a reinforcing filler. The surface of the hydroxyapatite particles was modified by using a coupling agent (citric, malic, acrylic or methacrylic acid). Five specimens of 14 different composites were prepared for each mechanical test: flexural strength, Young's modulus and Vickers hardness. Mean values and standard deviations were calculated, and ANOVA and Student Newman Keuls multiple comparison tests were applied (P < 0.05). RESULTS: The addition of 50-60 wt% of hydroxyapatite particles to the unfilled monomer mixtures led to the increase of both Young's modulus and surface hardness of the material, while the flexural strength decreased. In general, when microscopic instead of nanoscopic hydroxyapatite was used as a reinforcing filler, mechanical properties were favored. The mechanical properties were also improved by adding citric, acrylic or methacrylic acid as a coupling agent. CONCLUSIONS: An adequate surface modification of the hydroxyapatite particles conferred enhanced mechanical properties to the final dental composite. Microscopic-hydroxyapatite particles are preferred to nanoscopic ones.     

Temporomandibular joint ankylosis surgery in a child: case report

Temporomandibular joint ankylosis is one of the most significant disorders of the stomatognathic system because it causes pain associated with severe functional limitations, such as difficulty in chewing and psychological and clinical problems due to poor oral hygiene. These disorders are quite significant in children, since the treatment is even more complex due to the fact that the condylar region is a site of active growth. The earlier the diagnosis is established, the better the treatment prognosis. Ankylosis can be treated by interposition arthroplasty of the temporalis muscle fascia in conjunction with ipsilateral coronoidectomy. The purpose of the present study was to report a clinical case of temporomandibular joint ankylosis in a pediatric patient treated by interposition arthroplasty of the temporalis muscle fascia associated with coronoidectomy.