An audit into the timing of dental extractions pre-head and neck radiotherapy and the prevalence of osteoradionecrosis.

Objective It is recommended that radiotherapy for head and neck cancer commences ten days post-dental extractions to reduce the risk of osteoradionecrosis (ORN) of the jaw. However, consideration must be given to patients' survival which might be compromised by delaying radiotherapy for these patients. The records of 154 patients receiving radiotherapy to the head and neck were retrospectively reviewed between July 2016 and August 2017, at Queen Alexandra Hospital in Portsmouth, to identify patients who have developed ORN, associated risk factors and the relative timings of dental extractions compared to the guidelines of the Royal College of Surgeons (RCS).

Structural changes and biological responsiveness of an injectable and mouldable monetite bone graft generated by a facile synthetic method.

Brushite (dicalcium phosphate dihydrate) and monetite (dicalcium phosphate anhydrous) are of considerable interest in bone augmentation owing to their metastable nature in physiological fluids. The anhydrous form of brushite, namely monetite, has a finer microstructure with higher surface area, strength and bioresorbability, which does not transform to the poorly resorbable hydroxyapatite, thus making it a viable alternative for use as a scaffold for engineering of bone tissue. We recently reported the formation of monetite cements by a simple processing route without the need of hydrothermal treatment by using a high concentration of sodium chloride in the reaction mix of β-tricalcium phosphate and monocalcium phosphate monohydrate.

An in vitro assessment of gutta-percha coating of new carrier-based root canal fillings.

The first aim of this paper was to evaluate the push-out bond strength of the gutta-percha coating of Thermafil and GuttaCore and compare it with that of gutta-percha used to coat an experimental hydroxyapatite/polyethylene (HA/PE) obturator. The second aim was to assess the thickness of gutta-percha around the carriers of GuttaCore and HA/PE obturators using microcomputed tomography ( μ CT). Ten (size 30) 1 mm thick samples of each group (Thermafil, GuttaCore, and HA/PE) were prepared.

Zygomatic implants: the impact of zygoma bone support on biomechanics.

Maxillectomy and severely resorbed maxilla are challenging to restore with provision of removable prostheses. Dental implants are essential to restore esthetics and function and subsequently quality of life in such group of patients. Zygomatic implants reduce the complications associated with bone grafting procedures and simplify the rehabilitation of atrophic maxilla and maxillectomy.

Extrasinus zygomatic implant placement in the rehabilitation of the atrophic maxilla: three-dimensional finite element stress analysis.

Placement of zygomatic implants lateral to the maxillary sinus, according to the extrasinus protocol, is one of the treatment options in the rehabilitation of severely atrophic maxilla or following maxillectomy surgery in patients with head and neck cancer. The aim of this study was to investigate the mechanical behavior of a full-arch fixed prosthesis supported by 4 zygomatic implants in the atrophic maxilla under occlusal loading. Results indicated that maximum von Mises stresses were significantly higher under lateral loading compared with vertical loading within the prosthesis and its supporting implants.

Marginal bone loss influence on the biomechanics of single implant crowns.

Marginal bone loss, whether it is physiological or pathological, is one of the implant treatment complications. The biomechanical consequences of marginal bone loss could be catastrophic particularly when the abutment screw is at supraosseous level. This study aimed at investigating marginal bone loss influence on the biomechanics of single implant crown using finite element (FE) analysis.

Stress analysis of different post-luting systems: a three-dimensional finite element analysis.

Background: The longevity of endodontically treated teeth is usually determined by the adequacy of root canal treatments, coronal seal and favourable stress distribution within the remaining tooth tissues. The aim of this study was to investigate the influence of post material and luting cement on the biomechanics of endodontically treated teeth using three-dimensional finite element analysis (3-D FEA).

Methods: A 3 mm section of endodontically treated canine tooth was scanned and reconstructed for 3-D modelling and FE analyses.

A novel method of forming micro- and macroporous monetite cements.

Second to autologous bone grafts are the calcium phosphate cements (CPCs) used as synthetic bone substitutes due to their chemical similarity to the mineral component of bone. Their ability to conform to complex bone defects and excellent osteoconductivity also render them excellent scaffolds for bone tissue engineering, although they do have their own limitations. Calcium phosphates can be divided into two main categories, namely apatite and brushite.

Stress analysis of occlusal forces in canine teeth and their role in the development of non-carious cervical lesions: abfraction.

Non-carious cervical tooth lesions for many decades were attributed to the effects of abrasion and erosion mainly through toothbrush trauma, abrasive toothpaste, and erosive acids. However, though the above may be involved, more recently a biomechanical theory for the formation of these lesions has arisen, and the term abfraction was coined. The aim of this study was to investigate the biomechanics of abfraction lesions in upper canine teeth under axial and lateral loading conditions using a three-dimensional finite element analysis.

The impact of fractured endodontic file removal on vertical root fracture resistance: three-dimensional finite element analysis.

This study investigated by means of finite element analysis the influence of fractured file removal on root fracture resistance in an endodontically-treated canine. A 4mm fragment of an endodontic file was deliberately fractured in the apical third of an upper canine root and removed by ultrasonic tips. Micro-computed tomography scans were carried out before and after fractured file removal on the same tooth.

A comparison of 2D and 3D finite element analysis of a restored tooth.

The finite element method is widely used in dental research. The decision to use two-dimensional (2D) or three-dimensional (3D) modelling is dependent on many interrelated factors. The purpose of the present study was to compare and contrast 2D and 3D finite element analysis (FEA) in investigating the mechanical behaviour of a maxillary premolar restored with a full crown under similar conditions of axial and lateral occlusal loading.

Finite element analysis of fixed partial denture replacement.

The purpose of this study was to investigate, by means of the finite element method the mechanical behaviour of three designs of fixed partial denture (FPD) for the replacement of the maxillary first premolar in shortened dental arch therapy. Two-dimensional, linear, static finite element analyses were carried out to investigate the biomechanics of the FPDs and their supporting structures under different scenarios of occlusal loading. Displacement and stress distribution for each design of FPD were examined, with particular attention being paid to the stress variations along the retainer-abutment--and the periodontal ligament-bone interfaces.

Biomechanics of cantilever fixed partial dentures in shortened dental arch therapy.

Purpose: The purpose of the present study was to investigate, by means of 3-dimensional finite element analysis, aspects of the biomechanics of cantilever fixed partial dentures replacing the maxillary canine in shortened dental arch therapy. The null hypothesis was that no differences would be identified by finite element analysis in the mechanical behavior of the 2 designs of cantilever fixed partial denture under different scenarios of occlusal loading.

Materials And Methods: Single- and double-abutted cantilever fixed partial dentures were modeled and analyzed using the finite element packages PATRAN and ABAQUS.

The mechanical behaviour of cantilever fixed partial dentures in shortened dental arch therapy: a 2-D finite element analysis.

In the present study two-dimensional finite element models of two- and three-unit cantilever fixed partial dentures were created to simulate the replacement of a maxillary second premolar in a shortened dental arch. The purpose of the study was to investigate the mechanical behaviour of the two designs of fixed partial denture using the finite element method. The results indicate that the mechanical behaviour of the three-unit fixed partial denture was more favourable than that of the two-unit fixed partial denture under similar conditions of occlusal loading.