George Jayantha Dias

Reconstituted keratin–hydroxyapatite (K–HA) composites have shown potential as nonload-bearing bone graft substitute material. This in vivo study investigated the bone regeneration response of keratin plus 40% HA composite materials in comparison to collagen counterparts and an unfilled defect site. The implantation site was a noncritical size defect created in the long bones (tibia) of sheep, with observations made at 1, 2, 4, 6, 8, and 12 weeks postimplantation. Porous K–HA materials displayed an excellent biocompatibility similar to collagen counterparts; however, the rate of bone regeneration at K–HA implantation sites was markedly slower than that of the collagen or unfilled defect sites. While collagen materials were undetectable by 4 weeks implantation, K–HA composite remnants were present at 12 weeks. However, there is evidence that K–HA implants participated in the natural remodelling process of bone, with bone regeneration occurring via a creeping substitution mechanism. Observations imply that the rate of bone ingrowth into the K–HA defect site was matched with the rate of K–HA resorption. These results suggest that K–HA materials may offer significant benefits as nonload-bearing bone graft substitutes where it is desirable that the degradation of the scaffolding material be well matched with the rate of bone regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2034–2044, 2017.

The posterior deep temporal nerve (PDTN) groove accommodates the posterior deep temporal nerve and is infrequently described. This area is important for some clinical procedures including mandibular nerve blockade. This study assesses the prevalence and morphological variations of the PDTN groove in a single population, investigating its relationship with basicranial angle to assess predictive value for the existence of this feature. The infratemporal regions of 101 contemporary Sinhalese Sri Lankan skulls were examined bilaterally and ordinally scored for PDTN groove morphology (six point scale); 11 random skulls were radiographed and basicranial angles measured. Descriptive statistics and significance testing (P < 0.05) were used for analysis, including symmetry (Wilcoxon matched-pairs signed rank test), sex differences (Mann and Whitney U test), and between basicranial angle and PDTN morphology (Pearson’s product-moment correlation coefficient). Ninety skulls (44 males) were included for analysis (180 sides). PDTN groove morphology on individual sides ranged from non-existent (20.6 %) to partial (5.6 %) and complete canals (1.1 %); 93.3 % of skulls had a PDTN groove or canal. Skulls exhibited bilateral symmetry (P = 0.12) and males had significantly deeper PDTN grooves or canals (P = 0.018). Basicranial flexion correlated strongly with PDTN groove or canal prevalence (P = 0.0028). Sri Lankan skulls have a high prevalence of PDTN grooves and also canals, a feature not previously described. Prevalence was related significantly to sex but not symmetry, and PDTN grooves and canals correlated significantly with basicranial angle. Knowledge of this morphology is important for some clinical procedures, anthropological assessment, and as a location for PDTN entrapment.

Knowledge of the anatomy of the auriculotemporal nerve (ATN) and middle meningeal artery (MMA) in the infratemporal fossa is necessary for assisting concise medical diagnosis and intervention. Current textbook descriptions describe a relationship between these structures that is not reported in previous studies. In addition, no previous studies have reported on symmetry or ethnicity affecting the relationship between these structures. This study aims to provide information on the relationship between the ATN and the meningeal artery in a specific ethnic group to further our understanding of normal morphology in this region. The infratemporal fossae of 19 Caucasian cadaveric heads were dissected bilaterally and the relationship between the ATN and MMA scrutinised. Twenty-five samples were included for analysis, including 6 bilateral (12 sides, 8 female) and 13 unilateral (9 female) specimens. Nerve root contributions to the ATN from the mandibular and inferior alveolar nerve included 8 specimens with 1 root, 12 with 2, 5 with 3, and 1 with 4. Three of six bilaterally dissected specimens had asymmetrical numbers of nerve roots. Two specimens were found with a ‘button hole’ arrangement of the ATN; these did not enclose the MMA. Variation was found both between and within specimens in relation to the relationship between the ATN and MMA. None of the specimens examined demonstrated a morphology that was consistent with common anatomical texts. Findings suggest modern texts require revision in order to accurately describe the relationship between these structures.

The objective of this study was to determine if variation in the shape and mineralization of the mandibular condyle are the result of natural adaptation in response to different functional loading demands. Eight female Kuni Kuni piglets were randomly assigned to two groups of four, receiving either a soft or hard diet. Each animal was given three separate doses of vital stains intravenously at set time points during the study. At 8.5 months, animals were euthanized and temporomandibular joints (TMJs) were excised. Histological analysis was used to measure the amount of new bone deposition in the anterior, central, and posterior regions of the mandibular condyle. Backscatter electron (BSE) imaging was used as a semiquantitative estimate of bone mineralization in these two diet groups. Histology revealed that the degree of new bone deposition in the hard‐diet group was significantly (n = 4, P < 0.001, paired t‐test) higher than that of the soft‐diet group. Also, the majority (87%) of animals fed a hard diet tended to show greater new bone deposition on the leftside in comparison to the right, indicating a chewing preference for the left side. In both groups, the degree of new bone deposition was significantly (P < 0.01) higher in the posterior area than in other regions. BSE imaging corroborated basic histology results, with significantly (P < 0.01) higher mineralization levels detected in the hard‐diet group. These findings indicate that diet consistency has a small but significant effect on the rate of bone deposition in the mandibular condyle. Clin. Anat. 24:590–598, 2011.

Reconstituted keratin has shown promise as an orthopaedic biomaterial. Thisin vivostudy investigates the biological response of composite materials prepared from reconstituted keratin containing a high content of hydroxyapatite (HA) (40 wt % HA), implanted for up to 18 weeks in the long bones of sheep. Keratin–HA composites were compared with a commercially available polylactic acid (PLA) HA composite (BIO RCI HA®, Smith and Nephew). Porous keratin–HA materials displayed excellent biocompatibility and osseointegration, with full integration into bone by 12 weeks. Dense keratin–HA materials also showed excellent biocompatibility, with a more limited osseointegration, involving the penetration of new bone into the periphery of the implant after eight weeks. In contrast, the PLA–HA implant did not integrate with surrounding tissue. Microindentation showed that porous keratin–HA implants were initially soft, but became stiffer as new bone penetrated the implant from four weeks onwards. In contrast, although the initial rigidity of dense keratin–HA composites was maintained for at least two weeks, the implant material weakened after four weeks. The PLA–HA implant maintained its physical properties throughout the course of the trial. This study demonstrates the increased osseointegration/osteoconduction capacity of keratin–HA composites and provides further evidence supporting the suitability of keratin‐based materials, such as bone graft substitutes and soft tissue fixation devices. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.

Apical periodontal cysts are benign lesions developing in relation to the apices of non‐vital teeth due to inflammatory response from the infective pulp. These are epithelium‐lined bony cavities containing fluid. Despite being widely reported in medical/dental literature, this common condition is poorly diagnosed and documented in the archaeological literature. We aim to clarify the correct terminology, demonstrate bony manifestations at different stages of pathogenesis of chronic periapical dental lesions into granuloma and apical periodontal cysts, and to describe diagnostic criteria which would provide practical guidelines for the diagnosis of these conditions.Three identified skulls from the International Exchange Collection, housed in the Anthropological Museum at the University of Coimbra, are used to identify the progression of this condition from a small periapical granuloma to a large apical periodontal cyst with expansion of alveolar and facial bones. The pathogenesis of this condition is described, together with its surgical management in the early 20^th century in Portugal, which is the period in which these individuals lived. Confusion resulting from the different terminologies can be avoided if the term periapical granuloma is used to define apical bony lesions smaller than 3 mm at their maximum intra‐bony diameter, and the term apical periodontal cysts for the larger lesions. We recommend that these terminologies and parameters be used as a standard in future studies. This will make inter‐observer and inter‐population comparisons more accurate. Copyright © 2007 John Wiley & Sons, Ltd.