The Lived Experience of Informal Caregivers of People Who Have Severe Mental Illness and Coexisting Long-Term Conditions: A Qualitative Study.

BACKGROUND: People with severe mental illness (SMI) experience higher rates and poorer outcomes of physical long-term conditions (LTCs). The management of SMI and LTCs is highly complex and many people with SMI rely on informal carers for support, which may lead to high levels of caregiver burden, and caregiver burnout. Caregiver burnout can result in poor health outcomes for informal carers and a reduction in the quality of care they are able to provide. Therefore, it is important to understand the caring experience to identify and address factors that contribute to burden and burnout. METHODS: This paper reports a secondary qualitative analysis of semistructured interviews and focus groups conducted with informal carers of people who have coexisting SMI and LTCs. We recruited 12 informal carers in England between December 2018 and April 2019. The transcripts were coded and analysed thematically. RESULTS: We identified two overarching themes and five subthemes. The themes included 'Fighting on all fronts: Mounting strain between demands and resources', which described the challenge of providing care in the context of coexisting SMI and LTCs, and 'Safekeeping: The necessity of chronic hypervigilance', which captured how informal carers' roles were defined by managing high-risk situations, leading to hypervigilance and paternalistic approaches to care. CONCLUSION: The experience of informal carers for people with SMI and coexisting LTCs is marked by limited access to support and the management of significant risk, which could contribute to high caregiver burden. Further primary research is needed to understand how the experiences of the caregiver role for people with SMI and LTCs influence caregiver burden. PATIENT OR PUBLIC CONTRIBUTION: Our PPI panel DIAMONDS Voice provided guidance on this study from conception, design and development of interview guides and recruitment materials to final write-up. DIAMONDS Voice consists of service users and carers who have experience of SMI and LTCs. Three carer members reviewed the final manuscript, and two are credited as authors.

The lived experience of severe mental illness and long-term conditions: a qualitative exploration of service user, carer, and healthcare professional perspectives on self-managing co-existing mental and physical conditions.

BACKGROUND: People with severe mental illness (SMI), such as schizophrenia, have higher rates of physical long-term conditions (LTCs), poorer health outcomes, and shorter life expectancy compared with the general population. Previous research exploring SMI and diabetes highlights that people with SMI experience barriers to self-management, a key component of care in long-term conditions; however, this has not been investigated in the context of other LTCs. The aim of this study was to explore the lived experience of co-existing SMI and LTCs for service users, carers, and healthcare professionals. METHODS: A qualitative study with people with SMI and LTCs, their carers, and healthcare professionals, using semi-structured interviews, focused observations, and focus groups across the UK. Forty-one interviews and five focus groups were conducted between December 2018 and April 2019. Transcripts were coded by two authors and analysed thematically. RESULTS: Three themes were identified, 1) the precarious nature of living with SMI, 2) the circularity of life with SMI and LTCs, and 3) the constellation of support for self-management. People with co-existing SMI and LTCs often experience substantial difficulties with self-management of their health due to the competing demands of their psychiatric symptoms and treatment, social circumstances, and access to support. Multiple long-term conditions add to the burden of self-management. Social support, alongside person-centred professional care, is a key facilitator for managing health. An integrated approach to both mental and physical healthcare was suggested to meet service user and carer needs. CONCLUSION: The demands of living with SMI present a substantial barrier to self-management for multiple co-existing LTCs. It is important that people with SMI can access person-centred, tailored support for their LTCs that takes into consideration individual circumstances and priorities.

3D-printing-assisted fabrication of chitosan scaffolds from different sources and cross-linkers for dental tissue engineering.

The aim of the present study was to fabricate and characterise chitosan scaffolds from animal and fungal sources, with or without gelatine as a co-polymer, and cross-linked to 3-glycidyloxyproply trimethoxysilane (GPTMS) or genipin for application in dental root tissue engineering. Chitosan-based scaffolds were prepared by the emulsion freeze-drying technique. Scanning electron microscopy (SEM) and nano-focus computed tomography (nano-CT) were used to characterise scaffold microstructure. Chemical composition and cross-linking were evaluated by Fourier transform infrared-attenuated total reflectance spectroscopy. Compression tests were performed to evaluate scaffold mechanical properties. Scaffold degradation was evaluated by gravimetric method and SEM. Scaffold bioactivity immersed in simulated body fluid was evaluated by SEM, with associated electron dispersive X-ray spectroscopy, and apatite formation was examined by X-ray diffraction. Finally, human dental pulp stem cells (hDPSCs) viability was evaluated. The fabrication method used was successful in producing scaffolds with organised porosity. Chitosan source (animal vs. fungal), co-polymerisation with gelatine and cross-linking using GPTMS or genipin had a significant effect on scaffold properties and hDPSCs response. Chitosan-genipin (CS-GEN) scaffolds had the largest pore diameter, while the chitosan-gelatine-GPTMS (CS-GEL-GPTMS) scaffolds had the smallest. Animal chitosan-gelatine co-polymerisation increased scaffold compressive strength, while fungal chitosan scaffolds (fCS-GEL-GPTMS) had the fastest degradation rate, losing 80 % of their weight by day 21. Gelatine co-polymerisation and GPTMS cross-linking enhanced chitosan scaffolds bioactivity through the formation of an apatite layer as well as improved hDPSCs attachment and viability. Tailored chitosan scaffolds with tuned properties and favourable hDPSCs response can be obtained for regenerative dentistry applications.

Effect of extracellular matrix and dental pulp stem cells on bone regeneration with 3D printed PLA/HA composite scaffolds.

The demand for bone grafting procedures in various fields of medicine is increasing. Existing substitutes in clinical practice do not meet all the criteria required for an ideal bone scaffold, so new materials are being sought. This study evaluated bone regeneration using a critical-size Wistar rat's calvarial defect model. 12 male and 12 female rats were evenly divided into 3 groups: 1. Negative and positive (Geistlich Bio-Oss®) controls; 2. polylactic acid (PLA) and PLA/hydroxyapatite (HA); 3. PLA/HA cellularised with dental pulp stem cells (DPSC) and PLA/HA extracellular matrix (ECM) scaffolds. PLA/HA filament was created using hot-melt extrusion equipment. All scaffolds were fabricated using a 3D printer. DPSC were isolated from the incisors of adult Wistar rats. The defects were evaluated by micro-computed tomography (µCT) and histology, 8 weeks after surgery. µCT revealed that the Bio-Oss group generated 1.49 mm3 and PLA/HA ECM 1.495 mm3 more bone volume than the negative control. Histology showed a statistically significant difference between negative control and both (Bio-Oss and PLA/HA ECM) groups in rats of both genders. Moreover, histology showed gender-specific differences in all experimental groups and a statistically significant difference between cellularised PLA/HA and PLA/HA ECM groups in female rats. Qualitative histology showed the pronounced inflammation reaction during biodegradation in the PLA group. In conclusion, the bone-forming ability was comparable between the Bio-Oss and PLA/HA ECM scaffolds. Further research is needed to analyse the effects of ECM and PLA/HA ratio on osteoregeneration.

Clinical applications, accuracy and limitations of guided endodontics: a systematic review.

BACKGROUND: The novel concept of guided endodontics has been reported as an effective method to obtain safe and reliable results in root canal treatment. AIM: To evaluate by means of a systematic review the clinical applications, accuracy and limitations of guided endodontic treatment. DATA SOURCES: A search of the literature was performed on PubMed, Embase, Web of Science and Cochrane Library databases, until 25 April 2019. No language or year restrictions were applied. STUDY ELIGIBILITY CRITERIA: Articles that answered the research question, including case reports, in vitro and ex vivo studies were included. Data extraction was performed independently by two reviewers. STUDY APPRAISAL: Quality assessment was done using STROBE, CARE and Modified CONSORT guidelines for observational, case reports and pre-clinical studies, respectively. RESULTS: A total of 22 articles, including fifteen case reports, six pre-clinical studies (in vitro and ex vivo studies) and one observational study, were included. LIMITATIONS AND CONCLUSIONS: Even though the level of evidence is low, and the methodology described among studies heterogeneous, all articles describe guided access cavity preparation and guided surgery as being highly accurate and successful techniques when comparing the drilled path to the planned treatment. More studies with a larger number of patients are necessary to obtain significant conclusions.

Microguided Endodontics: a case report of a maxillary lateral incisor with pulp canal obliteration and apical periodontitis.

AIM: To describe a minimally invasive method to create a 3D-printed guide to gain access to obliterated root canals on the basis of CBCT data. SUMMARY: A 85-year-old female ASA III was referred for root canal treatment of tooth 22. Clinically, there were no complaints, no percussion pain or sinus tract. Radiologically, the tooth had an obliterated canal with an apical radiolucency. The tooth was diagnosed with asymptomatic apical periodontitis. Microguided Endodontic treatment was performed with the help of a 3D-printed guide. The root canal was localized initially with the aid of the 3D-printed guide using a round carbide bur with a head diameter of 0.8 mm. Then, the canal was shaped and cleaned using mechanical rotary files under copious irrigation with 5% NaOCl, 17% EDTA and passive ultrasonic activation. A completely healed apical area of tooth 22 was visible after 6 months on periapical radiographs and small field of view CBCT. KEY LEARNING POINTS: Using the Microguided Endodontics concept, a minimally invasive access was achieved up to the middle of the root, in a maxillary lateral incisor with pulp canal obliteration (PCO) and apical periodontitis. This technique is a valuable tool for the negotiation of PCO, reducing chair time and risk of iatrogenic damage to the root.

[Bilateral autogenous transplantation of impacted maxillary canines]. / Bilaterale autologe transplantatie van geïmpacteerde maxillaire cuspidaten.

In a fifteen-year-old girl, bilaterally impacted permanent maxillary canines were established. A difficult palatinal placement and an apical deviation were found in both teeth. Surgical exposure of the canines, followed by orthodontic traction was not desirable. Both remaining primary canines showed signs of resorption. Autogenous transplantation of the maxillary canines was the treatment chosen.

Socioeconomic inequalities in duration of untreated psychosis: evidence from administrative data in England.

BACKGROUND: Duration of untreated psychosis (DUP) is an important measure of access to care as it predicts prognosis and treatment outcomes. Little is known about potential socioeconomic inequalities in DUP. The aim of this study was to investigate inequalities in DUP associated with socioeconomic deprivation in a national cohort in England. METHOD: We analysed a cohort of 887 patients with a first-episode in psychosis using the administrative Mental Health Services Dataset in England for 2012/13-2014/15. We used a Generalised Linear Model to account for non-linearity in DUP and looked at inequalities across the whole distribution of DUP using quantile regression. RESULTS: The median DUP was 22 days (mean = 74 days) with considerable variations between and within the 31 hospital providers. We found evidence of significant inequalities regarding the level of socioeconomic deprivation. Patients living in the second, third and fourth deprived neighbourhood quintiles faced a 36, 24 and 31 day longer DUP than patients from the least deprived neighbourhoods. Inequalities were more prevalent in higher quantiles of the DUP distribution. Unemployment prolonged DUP by 40 days. Having been in contact with mental health care services prior to the psychosis start significantly reduced the DUP by up to 53 days. CONCLUSIONS: Socioeconomic deprivation is an important factor in explaining inequalities in DUP. Policies to improve equitable access to care should particularly focus on preventing very long delays in treatment and target unemployed patients as well as people that have not been in contact with any mental health professional in the past.

The dietary form of choline during lactation affects maternal immune function in rats.

PURPOSE: The present study was designed to determine the effects of both choline form and availability on maternal immune function during lactation. METHODS: Sprague-Dawley rats were randomized to one of the three diets 24-48 h before parturition and fed ad libitum until 21 days postnatal: 1 g/kg choline as free choline (C, n = 11), the current form, and amount of choline in commercial diets; 1 g/kg choline as phosphatidylcholine (PC1, n = 11); or 2.5 g/kg choline as PC (PC2.5, n = 8). Choline metabolites in offspring stomach contents were quantified. At 21 days, lymphocytes from mothers' mesenteric lymph nodes and spleens were isolated and phenotypes and ex vivo cytokine production after mitogen exposure were determined. RESULTS: There was a higher proportion of choline and a lower proportion of lyso-PC in stomach contents (representing dam's milk) of C pups compared to PC1. In the mesenteric lymph nodes, feeding PC1 compared to C led to a higher IL-2 production after Concanavalin A (ConA) stimulation and a higher proportion of T cells (CD3+) and a lower proportion of B cells [immunoglobulin (Ig)κ, CD45RA+, and IgM+; P < 0.05]. Splenocytes from the PC1 group produced more IL-6 and TNF-α after lipopolysaccharides stimulation compared to C (P < 0.05). Splenocytes from the PC2.5 group produced more IL-2 and IL-6 after ConA stimulation compared to PC1 (P < 0.05). CONCLUSIONS: Feeding choline as PC in the maternal diet improved the ability of immune cells to respond ex vivo to mitogens and increasing the amount of PC in the diet further improved T cell proliferation.

Salivary biomarkers for oral cancer and pre-cancer screening: a review.

OBJECTIVE: The objective of the study was to conduct a systematic review of the literature assessing potential salivary biomarkers of oral cancer and pre-cancer and discuss emerging issues and challenges in relation to oral cancer and pre-cancer diagnostics. MATERIALS AND METHODS: Search for articles involved the Medline, PubMed, and EMBASE. Specific terms were used from January 1995 to March 2017 by three experts. RESULTS: This search collected 270 articles, of which 105 articles such as reviews, case reports, news, letter to editor, etc. in first round and 117 articles such as publications in other languages than English, non-human studies, etc. were excluded. The remaining 48 articles considered analyzing whole saliva as well as specific gland saliva. Thirty-one studies considered oral stimuli such as eating, drinking, and oral hygiene practices for varied periods of time prior to sample collection. The time of collection of saliva was morning in most studies, but the exact time of collection was not mentioned. Three studies showed to have evaluated the whole saliva without centrifugation. Two-dimensional gel electrophoresis and tandem mass spectrometry were the most commonly used methods. Most of the potential salivary biomarkers of oral cancer are salivary proteins. CONCLUSION: Combination approach of salivary biomarkers could be used as screening tool to improve early detection and diagnostic precision of oral pre-cancer and cancer. CLINICAL RELEVANCE: The current findings are of importance for clinicians and researchers to mitigate the challenges in salivary-based diagnosis of oral cancer and to evaluate reliable, specific, and sensitive salivary biomarkers for oral pre-cancer and cancer diagnosis.

mySinusitisCoach: patient empowerment in chronic rhinosinusitis using mobile technology.

Mobile health technology is emerging to take a prominent position in the management of chronic diseases. These technologies aim at enhancing patient empowerment via education and self-management. To date, of all the different apps available for patients with sinus disease, none were developed by medical experts dealing with chronic rhinosinusitis (CRS). The European Forum for Research and Education in Allergy and Airway diseases (EUFOREA) has undertaken a multi-stakeholder approach for designing, developing and implementing a tool to support CRS patients in monitoring their symptoms and to provide patients with a digital support platform containing reliable medical information about their disease and treatment options. mySinusitisCoach has been developed by medical experts dealing with CRS in close collaboration with patients, primary care physicians and community pharmacists, meeting the needs of both patients and health care providers. From a research perspective, the generation of real life data will help to validate clinical studies, patient stratification and improve understanding of the socio-economic impact of CRS, thereby paving the way for better treatment strategies.

Allergen exposure chambers: harmonizing current concepts and projecting the needs for the future - an EAACI Position Paper.

BACKGROUND: Allergen exposure chambers (AECs) are clinical facilities allowing for controlled exposure of subjects to allergens in an enclosed environment. AECs have contributed towards characterizing the pathophysiology of respiratory allergic diseases and the pharmacological properties of new therapies. In addition, they are complementary to and offer some advantages over traditional multicentre field trials for evaluation of novel therapeutics. To date, AEC studies conducted have been monocentric and have followed protocols unique to each centre. Because there are technical differences among AECs, it may be necessary to define parameters to standardize the AECs so that studies may be extrapolated for driving basic immunological research and for marketing authorization purposes by regulatory authorities. METHODS: For this task force initiative of the European Academy of Allergy and Clinical Immunology (EAACI), experts from academia and regulatory agencies met with chamber operators to list technical, clinical and regulatory unmet needs as well as the prerequisites for clinical validation. RESULTS: The latter covered the validation process, standardization of challenges and outcomes, intra- and interchamber variability and reproducibility, in addition to comparability with field trials and specifics of paediatric trials and regulatory issues. CONCLUSION: This EAACI Position Paper aims to harmonize current concepts in AECs and to project unmet needs with the intent to enhance progress towards use of these facilities in determining safety and efficacy of new therapeutics in the future.

[Chewing on bruxism. Diagnosis, imaging, epidemiology and aetiology]. / Kauwen op bruxisme. Diagnostiek, beeldvorming, epidemiologie en oorzaken.

Since the publication of a special issue on bruxism of the NTvT in July 2000, consensus has been reached on bruxism's definition as a repetitive masticatory muscle activity that is characterised by clenching and/or grinding while awake (awake bruxism) or during sleep (sleep bruxism). As yet, however, no consensus exists about the diagnosis of bruxism: sufficient evidence to establish the reliability and validity of the commonly used techniques (self-report, clinical examination, imaging, electromyography, polysomnography) has not yet been produced. Morphological factors are no longer considered important aetiological factors, while increasing evidence suggests aetiological roles for psychosocial, physiological, biological, and exogenous factors. This review paper is the first part of a diptych and is concerned with the definition, diagnostics, epidemiology and possible causes of this disorder. In the second part, that will be published in the next issue, associations of bruxism with other conditions will be discussed, along with its (purported) consequences and its management.

[Chewing on bruxism: associations, consequences and management]. / Kauwen op bruxisme. Associaties, gevolgen en behandeling.

In this second part of a diptych on bruxism, the focus is on the associations of this masticatory muscle activity with other sleep-related conditions. Its association with the obstructive sleep apnoea syndrome (OSAS) has been a particular object of study. Bruxism seems to play a protective role in OSAS, although the evidence for this is not yet conclusive. Apart from this possible positive consequence, bruxism also has several negative consequences, for which evidence is available to a greater or lesser extent. For example, bruxism has been associated with temporomandibular pain and dysfunction, periodontal and endodontic problems, failures of restorations and implants, and tooth wear. In some cases, these consequences are severe enough to justify treatment of bruxism. In all other cases, there is no indication for diagnostics and treatment, given the possible positive consequences. If treatment is indicated, modalities should be conservative, like stabilisation appliances, counselling, medication, psychology, and physiotherapy.

Decoupling of the amygdala to other salience network regions in adolescent-onset recurrent major depressive disorder.

BACKGROUND: Recent meta-analyses of resting-state networks in major depressive disorder (MDD) implicate network disruptions underlying cognitive and affective features of illness. Heterogeneity of findings to date may stem from the relative lack of data parsing clinical features of MDD such as phase of illness and the burden of multiple episodes. METHOD: Resting-state functional magnetic resonance imaging data were collected from 17 active MDD and 34 remitted MDD patients, and 26 healthy controls (HCs) across two sites. Participants were medication-free and further subdivided into those with single v. multiple episodes to examine disease burden. Seed-based connectivity using the posterior cingulate cortex (PCC) seed to probe the default mode network as well as the amygdala and subgenual anterior cingulate cortex (sgACC) seeds to probe the salience network (SN) were conducted. RESULTS: Young adults with remitted MDD demonstrated hyperconnectivity of the left PCC to the left inferior frontal gyrus and of the left sgACC to the right ventromedial prefrontal cortex (PFC) and left hippocampus compared with HCs. Episode-independent effects were observed between the left PCC and the right dorsolateral PFC, as well as between the left amygdala and right insula and caudate, whereas the burden of multiple episodes was associated with hypoconnectivity of the left PCC to multiple cognitive control regions as well as hypoconnectivity of the amygdala to large portions of the SN. CONCLUSIONS: This is the first study of a homogeneous sample of unmedicated young adults with a history of adolescent-onset MDD illustrating brain-based episodic features of illness.

Feeding a diet devoid of choline to lactating rodents restricts growth and lymphocyte development in offspring.

The nutrient choline is necessary for membrane synthesis and methyl donation, with increased requirements during lactation. The majority of immune development occurs postnatally, but the importance of choline supply for immune development during this critical period is unknown. The objective of this study was to determine the importance of maternal supply of choline during suckling on immune function in their offspring among rodents. At parturition, Sprague-Dawley dams were randomised to either a choline-devoid (ChD; n 7) or choline-sufficient (ChS, 1 g/kg choline; n 10) diet with their offspring euthanised at 3 weeks of age. In a second experiment, offspring were weaned to a ChS diet until 10 weeks of age (ChD-ChS, n 5 and ChS-ChS, n 9). Splenocytes were isolated, and parameters of immune function were measured. The ChD offspring received less choline in breast milk and had lower final body and organ weight compared with ChS offspring (P<0·05), but this effect disappeared by week 10 with choline supplementation from weaning. ChD offspring had a higher proportion of T cells expressing activation markers (CD71 or CD28) and a lower proportion of total B cells (CD45RA+) and responded less to T cell stimulation (lower stimulation index and less IFN-γ production) ex vivo (P<0·05). ChD-ChS offspring had a lower proportion of total and activated CD4+ T cells, and produced less IL-6 after mitogen stimulation compared with cells from ChS-ChS (P<0·05). Our study suggests that choline is required in the suckling diet to facilitate immune development, and choline deprivation during this critical period has lasting effects on T cell function later in life.

A survey of US and Canadian hospitals' paediatric massive transfusion protocol policies.

BACKGROUND: Trauma is the leading cause of death in children >1 year of age, with haemorrhage as the most common cause of medically preventable deaths. While massive transfusion protocols (MTPs) have been investigated and used in adults to reduce death from haemorrhage, there are a paucity of published data on MTP practices and outcomes in children. This study aimed to survey current MTP policies and the frequency of activation at paediatric care centres. STUDY DESIGN AND METHODS: We conducted a survey of MTPs at hospitals in the United States and Canada, including children's general hospitals, children's specialty hospitals and children's units in general hospitals. We collected information on how the MTP is activated, what therapeutics are given, frequency of its use, and how it is audited for compliance. RESULTS: Forty-six survey responses were analysed. Physician discretion was the most common activation criteria (89%). A majority of sites (78%) targeted a 'high' (≥1 : 2) ratio of plasma to red blood cells (RBC). Fifteen percent of sites use antifibrinolytics in their MTPs. Eighty nine percent of sites have type-O RBC units and 48% of sites had thawed plasma units stored in an immediately available location. CONCLUSION: There is a wide variation in MTPs among paediatric hospitals with regard to both activation criteria and products administered. This underscores the need for future prospective studies to determine the most effective resuscitation methods for paediatric populations to improve outcomes and therapeutic safety for massive bleeding.

The BMP pathway either enhances or inhibits the Wnt pathway depending on the SMAD4 and p53 status in CRC.

BACKGROUND: Constitutive Wnt activation is essential for colorectal cancer (CRC) initiation but also underlies the cancer stem cell phenotype, metastasis and chemosensitivity. Importantly Wnt activity is still modulated as evidenced by higher Wnt activity at the invasive front of clonal tumours termed the ß-catenin paradox. SMAD4 and p53 mutation status and the bone morphogenetic protein (BMP) pathway are known to affect Wnt activity. The combination of SMAD4 loss, p53 mutations and BMP signalling may integrate to influence Wnt signalling and explain the ß-catenin paradox. METHODS: We analysed the expression patterns of SMAD4, p53 and ß-catenin at the invasive front of CRCs using immunohistochemistry. We activated BMP signalling in CRC cells in vitro and measured BMP/Wnt activity using luciferase reporters. MTT assays were performed to study the effect of BMP signalling on CRC chemosensitivity. RESULTS: Eighty-four percent of CRCs with high nuclear ß-catenin staining are SMAD4 negative and/or p53 aberrant. BMP signalling inhibits Wnt signalling in CRC only when p53 and SMAD4 are unaffected. In the absence of SMAD4, BMP signalling activates Wnt signalling. When p53 is lost or mutated, BMP signalling no longer influences Wnt signalling. The cytotoxic effects of 5-FU are influenced in a similar manner. CONCLUSIONS: The BMP signalling pathway differentially modulates Wnt signalling dependent on the SMAD4 and p53 status. The use of BMPs in cancer therapy, as has been proposed by previous studies, should be targeted to individual cancers based on the mutational status of p53 and SMAD4.

Depth and lateral deviations in guided implant surgery: an RCT comparing guided surgery with mental navigation or the use of a pilot-drill template.

AIM: To assess the accuracy of guided surgery compared with mental navigation or the use of a pilot-drill template in fully edentulous patients. MATERIAL AND METHODS: Sixty consecutive patients (72 jaws), requiring four to six implants (maxilla or mandible), were randomly assigned to one of the following treatment modalities: Materialise Universal(®) mucosa, Materialise Universal(®) bone, Facilitate(™) mucosa, Facilitate(™) bone, mental navigation, or a pilot-drill template. Accuracy was assessed by matching the planning CT with a postoperative CBCT. Deviations were registered in a vertical (depth) and horizontal (lateral) plane. The latter further subdivided into BL (bucco-lingual) and MD (mesio-distal) deviations. RESULTS: The overall mean vertical deviation for the guided surgery groups was 0.9 mm ± 0.8 (range: 0.0-3.7) and 0.9 mm ± 0.6 (range: 0.0-2.9) in a horizontal direction. For the non-guided groups, this was 1.7 mm ± 1.3 (range: 0.0-6.4) and 2.1 mm ± 1.4 (range 0.0-8.5), respectively (P < 0.05). The overall mean deviation for the guided surgery groups in MD direction was 0.6 mm ± 0.5 (range: 0.0-2.5) and 0.5 mm ± 0.5 (range: 0.0-2.9) in BL direction. For the non-guided groups, this was 1.8 mm ± 1.4 (range: 0.0-8.3) and 0.7 mm ± 0.6 (range 0.0-2.9), respectively. The deviation in MD direction was significantly higher in the non-guided groups (P = 0.0002). CONCLUSION: The most important inaccuracy with guided surgery is in vertical direction (depth). The inaccuracy in MD or BL direction is clearly less. For non-guided surgery, the inaccuracy is significantly higher.

Artefact expression associated with several cone-beam computed tomographic machines when imaging root filled teeth.

AIM: To evaluate the characteristic artefact patterns associated with teeth root filled with Gutta-percha when scanned with four cone-beam CT devices. METHODOLOGY: Whilst using soft tissue simulation, ten root filled human premolars were placed in empty sockets in a dry human skull. Subsequently, the skull was scanned using 3D Accuitomo 170(®) , WhiteFox(®) , Cranex 3D(®) and Scanora 3D(®) following clinical protocols with the highest resolution and artefact reduction. After proper image registration in OnDemand3D(®) software (Cybermed, Seoul, Korea), each image slice was evaluated by three trained and calibrated dentomaxillofacial radiologists, which scored absence (0) and presence (1) of cupping artefact, hypodense halos and streak artefacts. Kappa test was performed for intra- and interobserver agreement. RESULTS: A moderate to perfect agreement for each observer (intra-observer κ = 0.5-1.0) was found. Agreement between the different observers was moderate to almost perfect for the different artefact patterns (interobserver κ = 0.55-0.9). Cupping artefact was the most prevalent (70%), followed by a hypodense halo (35%) and streak artefacts (16%). The Chi-squared test revealed significantly more streaks in axial slices (P < 0.0001), with some CBCT systems yielding significantly inferior results to others (P < 0.05). The dedicated EndoMode and artefact reduction did not improve the result significantly. CONCLUSIONS: The variation of artefact expression was significantly different amongst CBCT machines for root filled teeth. Continuous efforts are needed to improve CBCT reconstruction algorithms, with a specific focus on reducing artefacts induced by dense dental materials, whilst striving for enhanced image quality at low-radiation doses.