Assessment of Psychological Disturbance in Patients with Tooth Loss: A Systematic Review of Assessment Tools.

PURPOSE: To systematically review the available evidence on screening tools to detect the psychological disturbance in patients with tooth loss and technically successful removable dentures (partial and complete). MATERIALS AND METHODS: The study protocol was registered with the National Institute of Health Research Database (I.D. CRD42017082125). The PICOS tool (patients, intervention, control, outcomes measure, and study design) was used to formulate an effective search strategy. Participants were adults (≥ 18), who were edentulous or had significant tooth loss (< 9 remaining teeth). The intervention included undergoing replacement with technically successful dentures (partial or complete). A control group of adults were either edentulous or had significant tooth loss and without dentures. Outcomes included assessing psychological disturbance due to treatment with dentures or due to no treatment using a validated tool. A structured search strategy was used to complete a standard systematic search of the electronic database without any date limit and/or language restriction. Only quantitative studies using a validated measuring tool to screen for psychological distress in adults with significant tooth loss were included. Two authors independently assessed the risk of bias in the included studies. Data homogeneity was assessed in regards to the screening tools to measure psychological disturbance following the management of tooth loss with dentures. The significant level was set at 0.05, using IBM SPSS Statistics 24.0 (SPSS Inc., New York, NY). The psychometric properties and the validation processes of the screening tools were assessed. RESULTS: From the original 3510 studies identified, only eight studies were found to meet the inclusion criteria. All eight studies used the same questionnaire to screen for the emotional distress of tooth loss. In addition, one study also used the Patient Health Questionnaire-9 (PHQ-9) to screen for the association of depression with tooth loss. Six studies suggested that a significant number of patients have difficulties in accepting tooth loss, were less confident, and had emotional distress related to tooth loss. However, two studies reported no significant link. All studies found a marked impact on functional activities and social interaction. However, four studies had a potentially biased selection process, and the questionnaire used was assessed to be at high-risk of measurement bias, as the development and validation process was not clear. There was also a lack of well-defined control groups in all studies. CONCLUSION: Tooth loss could cause psychological disturbance in some patients. To date, there is a lack of available tools that are suitable to screen and measure psychological disturbance in patients with tooth loss. Additional research is required to develop tools to identify and measure such impact and to recommend suitable interventions when needed.

Volume Assessment of the Effect of Obturators on Facial Form Following Surgery for Head and Neck Cancer Using Stereophotogrammetry.

PURPOSE: To determine if stereophotogrammetry could be used to determine the effects of obturators on facial contour in relation to the measurement of facial volumes. MATERIALS AND METHODS: Stereophotogrammetry images were recorded from 20 subjects with and without their obturators in place. These were converted into a stereolithographic format and overlaid. Registrations were made using the tissues on the normal areas of the face. Difference images were created, enabling surface areas and volumes to be calculated. To assess repeatability of measurement, 2 readings were recorded on each of 2 separate registrations. Data analysis between the sets of readings used correlation coefficients and paired t-tests. Coefficients of repeatability were also calculated. RESULTS: A comparison of readings for the surface areas showed the method of measurement was repeatable with no significant differences between the 2 repeated readings for registration 1 (p = 0.977, coefficient of repeatability = 101 mm2 ), registration 2 (p = 0.085, coefficient of repeatability = 106 mm2 ), and the mean of the two readings for registration 1 compared with registration 2 (p = 0.355, coefficient of repeatability = 103 mm2 ). Similar results were found for the volume measurements with no significant differences between the repeated readings for registration 1 (p = 0.862, coefficient of repeatability = 229 mm3 ), registration 2 (p = 0.200, coefficient of repeatability = 209 mm3 ), and the mean of the 2 readings for registration 1 compared with those for registration 2 (p = 0.131, coefficient of repeatability 339 mm3 ). There was a statistically significant range of volumes that appeared to have been restored by the obturators (p < 0.0005). CONCLUSIONS: Stereophotogrammetry is reliable in assessing the effects of obturators on facial form. In the sample of subjects, obturators generally appeared to be effective in supporting facial tissues following surgical resections of the maxilla and therefore contribute in some degree to the restoration of facial appearance.

The Effect of Radiotherapy for Treatment of Head and Neck Cancer on Oral Flora and Saliva.

PURPOSE: Radiotherapy causes xerostomia in patients treated for head and neck cancer. This study investigated changes in quality and quantity of saliva after radiotherapy and possible associations between these changes and alterations in oral flora. MATERIALS AND METHODS: The study was a prospective cohort study of patients receiving radiotherapy for head and neck cancer. Suitable patients were recruited before treatment commenced, and informed consent was obtained. Patients were examined, and provided unstimulated and stimulated saliva samples. Quantity of saliva, buffering capacity and pH were measured. Oral flora was cultured from the saliva samples. Oral clearance of glucose and of lactose was measured. These interventions were repeated at intervals after radiotherapy had been completed. RESULTS: Eighteen patients were recruited. Stimulated and unstimulated saliva flow rates, glucose clearance, salivary pH and buffering capacity were significantly reduced after radiotherapy. Candida albicans counts were significantly increased. These increases were significantly correlated with reductions in stimulated and unstimulated salivary flow rates. Counts of lactobacilli, Streptococcus mutans and Bifidobacteriaceae increased, but not statistically significantly. CONCLUSIONS: Therapeutic radiotherapy significantly reduced the quality and quantity of saliva in head and neck cancer patients. These reductions were associated with increased C. albicans counts.

Two-piece obturator using "lock-and-key" mechanism.

This paper describes a method used for the fabrication of a two-piece denture obturator for a patient who had surgical removal of the premaxilla due to squamous cell carcinoma. The patient had been wearing a two-piece obturator but encountered difficulty in inserting the prosthesis. In this case report, a lock-and-key mechanism was used to easily assemble the two-piece prosthesis intraorally. A keyhole was designed on the obturator to act as the lock while the denture was used as the key that fitted into the keyhole. This mechanism facilitated insertion and provided retention for the prosthesis. Heat-cured resilient acrylic material (Molloplast B®), which was used to fabricate the obturator, was a nonirritant, nontoxic, tissue-compatible material. It also did not contain plasticizers, therefore eliminating the problems associated with leaching out of plasticizers. The use of this flexible and resilient material allowed the obturator to engage in the undercuts without causing trauma and irritation to the soft tissues in the region of the defect. To conclude, the "lock-and-key" mechanism used in the fabrication of the two-piece denture obturator provided the patient with a lightweight, comfortable, and user-friendly form of prostheses.

The role of the general dental practitioner in managing the oral care of head and neck oncology patients.

UNLABELLED: The general dental practitioner (GDP) plays a critical role in managing head and neck cancer patients. The first and most important role is to offer preventive services, particularly to smokers and to patients who drink alcohol to excess. It is of critical importance that every patient has a systematic examination of oral soft tissues when seen by a GDP. All patients with suspicious lesions should be referred for urgent attention to a specialist centre. Once oral cancer has been diagnosed, GDPs may be presented with patients requiring urgent dentistry, including extractions before commencement of treatment, requiring palliation of symptoms during treatment, or requiring general dentistry after treatment. Radiotherapy provides increased survival but has serious adverse consequences, which may be lifelong, including dry mouth, radiation caries, limitation of mouth opening and high risk of osteonecrosis after extractions. Extraction of teeth in irradiated bone should be referred to specialist centres. Improving survival rates and an ageing population mean that GDPs will see many more survivors of head and neck cancer in the future, with an increased burden of dental care in the longer-term and an increased need for monitoring and secondary prevention. CLINICAL RELEVANCE: The management of patients with head and neck cancer is complex and involves a multi-disciplinary team, both in the primary treatment but also in the long-term care. This paper reviews the consequences of treatment for head and neck cancer and gives practical advice for GDPs and their team in the long-term care of these patients.

Do Tooth Loss and Dentures Cause Body Image Disturbance?

PURPOSE: To investigate the psychologic morbidities associated with tooth loss despite treatment with technically successful dentures. MATERIALS AND METHODS: This cross-sectional questionnaire-based study compared the psychologic disturbance and functional difficulties in two groups: individuals with tooth loss who wore optimal-quality removable dentures (test group), and individuals with tooth loss who did not wear dentures (control group). The questionnaire used was developed and validated previously. The short-form revised Eysenck personality questionnaire was also used to assess the relationship with personality traits. A total of 138 participants were recruited (denture group = 70; control group = 68). RESULTS: There was a significant difference in body image dissatisfaction between the groups (χ2 = 7.72, P value = .005). The denture group had 5.75-times higher probability than the control group of suffering from body image disturbance. Older patients were predicted to have 75% less probability of body image disturbance (OR = 0.25), and men were predicted to have up to 70% less disturbance (OR = 0.3). As for psychologic morbidities, participants in both groups presented with somatic symptoms related to depression or anxiety, which were nearly double that expected in the general population (15.7% and 7.8%, respectively). Furthermore, participants who complained about body image impairment were more likely to have higher scores on the neuroticism scale (OR = 3.64). CONCLUSION: Tooth loss and dentures could be associated with body image dissatisfaction and psychologic morbidity. Planning for patient-centered care is paramount prior to extracting any teeth and providing replacement options.

Dentists' perspectives on denture provision after radiotherapy for head and neck cancer: an exploratory study using the theoretical domains framework.

Introduction Patients are often keen to replace their missing teeth after radiotherapy for head and neck cancer (HNC), yet such replacement does not always take place.Aims This study aimed to investigate the influences on dentists' provision of dentures for patients treated with radiotherapy for HNC, including whether risk of osteoradionecrosis (ORN) is a factor influencing intention to provide dentures.Methods An online cross-sectional survey including a case scenario, self-reported behaviour and measures of factors (selected using the theoretical domains framework) that may affect dentists' decisions was completed by general dental practitioners (n = 150) and HNC multidisciplinary team dentists (n = 25) in England.Results Dentists' reluctance to provide dentures for HNC patients post-radiotherapy was often due to concerns about dry mouth and radiation caries rather than risk of ORN. Knowledge of guidelines and beliefs about consequences were independently associated with dentists' intention to replace missing teeth with dentures.Conclusion The likelihood of replacing missing teeth with dentures increased with awareness of clinical guidance on the use of dentures in HNC and that denture provision would have positive consequences that outweigh the costs.

Developing a questionnaire to measure psychological disturbance associated with tooth loss.

OBJECTIVES: To develop and validate a self-reporting measure to assess the psychological disturbance in adult patients with tooth loss and dentures Methods: Ethical approval obtained from the Health Research Authority NHS England (Ref:17/NI/0098). 128 participants (100 patients - 28 clinicians) were recruited to participate in the development and validation of the questionnaire. Inclusion criteria included adults (age ≥18) with tooth loss/dentures. Exclusion criteria included patients with a history of psychotic mental illness or patients who had treatment with dental implants. The development processes included: Phase 1. Development of questionnaire: describing the aims/target population of the questionnaire, generating a pool of items, defining the constructs to be measured, adapting psychological morbidity screening tools, Items reduction and producing a preliminary questionnaire. Phase 2. Validation of questionnaire: content validation, face validation, establishing construct validity, pilot testing and establishing reliability. RESULTS: Face and content validation indicated that the questionnaire was an appropriate tool to measure the impact of tooth loss and related psychological morbidities. Reliability analysis (Test re-test reliability/internal consistency) indicated the questionnaire has satisfactory reliability (correlation >0.7). Testing the theoretical hypothesis structure of the impact of tooth loss has also enhanced the construct validity of the questionnaire (domains correlated mildly (r>5 & <3) to strongly (r>5). Pilot testing confirmed the scale adequacy and wording clarity (>90 % of respondents). Results indicated that the developed questionnaire has adequate psychometric properties. CONCLUSION: A disease-specific measure that assesses the psychological impact of tooth loss and the effectiveness of interventions (i.e. dentures) has been developed and validated. CLINICAL SIGNIFICANT: A patient outcome measure was developed which could be used to assess the psychological impact of tooth loss and compare the effectiveness of various interventions like dentures and implants.

Use of dentures, receipt of information, quality of life, and oral function following radiotherapy for head and neck cancer.

BACKGROUND: Teeth with a poor prognosis are often extracted prior to radiotherapy for head and neck cancer (HNC) in order to help prevent the need for dental treatment after radiotherapy that might in turn lead to the development of osteoradionecrosis. However, the details and impact of replacing missing teeth after radiotherapy for HNC have received little attention, especially from the patients' perspective. AIMS: This study aimed to assess the use, satisfaction, and impact of denture use following radiotherapy for HNC. The study also sought to determine patients' satisfaction with information about replacing their missing teeth postradiotherapy. Finally, this study also aimed to assess interest in replacing missing teeth for those who had not done so. METHODS: A structured, validated, and reliable questionnaire was sent to HNC patients who had received radiotherapy and had missing teeth at the time of discharge. In addition to demographic details and self-reported oral hygiene, the questionnaire included questions on use of (or interest in) dentures, satisfaction with dentures, satisfaction with information about replacing missing teeth, QoL as measured by two questions from the short version of WHOQoL-BREF, and oral functioning as measured by BCSQ-H&N. Demographic details and clinical details were extracted from the hospital records. RESULTS: N = 80 (24%) returned a completed questionnaire. Participants had an average of 12 missing teeth (SD = 8.05). Most (n = 60, 75%) had not replaced their missing teeth. Of these, 35 (58%) were very or extremely interested in doing so. For HNC survivors who wore dentures, there was variable satisfaction and a number of side-effects of wearing dentures. Satisfaction with information about replacing missing teeth was low. There was no statistical difference in QoL or oral functioning between participants who wore dentures and participants who did not wear dentures. However, those with dentures reported fewer problems with carrying out daily routines as measured by the oral functioning tool. CONCLUSIONS: QoL and oral functioning were similar regardless of denture use, highlighting reduced oral function in both those with and without dentures. In those who had not replaced their missing teeth, there was substantial interest in doing so and thus may be an unmet need. The dental team could offer HNC survivors more support after radiotherapy and following denture provision to improve information about denture use and increase satisfaction with dentures.

Denture use and dental risk factors associated developing osteoradionecrosis after head and neck radiotherapy: A retrospective analysis of hospital records.

OBJECTIVES: This study aimed to assess the association between denture use and occurrence of osteoradionecrosis (ORN) following radiotherapy for head and neck cancer (HNC). MATERIALS AND METHODS: Medical records of 439 HNC patients treated with radiotherapy at Guy's & St Thomas' NHS Foundation Trust (London, UK) (2014-2019) who had missing teeth at the time of discharge were reviewed. Descriptive statistics were used to summarise the participant characteristics and outcome measures. Logistic regression analysis was used to identify factors associated with occurrence of ORN. RESULTS: Patients had an average of 14 missing teeth and 39 % wore dentures. Twenty-two (5 %) developed ORN. Out of 22 who developed ORN, 11 (50 %) wore dentures. Of these, 5 patients developed ORN in areas contacted by dentures. Denture use was not significantly associated with the occurrence of ORN (OR = 1.94; 95%CI = 0.79-4.81; p-value = 0.150). Longer duration of radiotherapy (OR =1.03; 95%CI = 1.00-1.06; p-value= 0.048) and more missing teeth in the lower anterior area (OR = 1.11; 95%CI = 1.01-1.22; p-value = 0.024) were significantly associated with the development of ORN. CONCLUSIONS: Within the limitations of this single-centre study in which few patients developed ORN, denture use may not be a risk factor for ORN following radiotherapy for HNC. This is likely to be the case if dentures are well-fitting and not causing sores or irritation. CLINICAL SIGNIFICANCE: Replacement of the missing teeth with dentures in HNC patients post-radiotherapy may be a suitable choice for many HNC survivors. However, a powered study in a large cohort that includes clinical evaluation of dentures and the quality of fit alongside denture wearing experience would be useful to further assess the impact of denture use on the development of ORN.

An investigation into the prevalence of combination syndrome.

OBJECTIVES: To investigate the prevalence of Combination Syndrome, and to investigate if provision of a mandibular removable partial denture has any influence on the prevalence of Combination Syndrome. METHOD: Patients attending Kings College London Dental Institute, Guys Hospital who wore maxillary conventional complete dentures opposing mandibular anterior teeth only, with or without mandibular partial dentures were examined by one examiner. Oral health, residual alveolar ridge and denture quality were assessed. Features putatively associated with Combination Syndrome were recorded. Patient ratings of dentures were recorded. RESULTS: 99 patients were recruited who were wearing maxillary removable complete dentures opposing only mandibular anterior teeth. Of these, 64 patients wore mandibular removable partial dentures and 35 patients did not. Only 8 patients displayed two features of Combination Syndrome and 38 patients displayed one feature of Combination Syndrome, excessive resorption of the anterior maxillary sextant. These findings are not compatible with previous research which suggested that the five features of Combination Syndrome were prevalent in patients wearing maxillary complete dentures opposing mandibular anterior teeth. CONCLUSIONS: Evidence supporting the existence of Combination Syndrome was not discovered in this research. Prevalence of Combination Syndrome appeared to be low or non-existent. Patient treatment modalities and teaching in relation to Combination Syndrome may need to be modified.

An audit of letters of referral to a prosthodontic department in a dental teaching hospital.

The purpose of this study was to investigate the quality and number of letters of referral for new patients received in the Prosthodontics Department of a Dental Teaching Hospital. Letters received during the month of May 2006 were included. Each letter of referral was tested against five criteria which might be expected in an appropriate letter of referral. These were information on the following: relevant dental history, relevant medical history, teeth present, diagnosis, and treatment plan. The results showed that only 8% of letters met all five criteria and 11% met none of them. Letters requesting better information were sent to referring practitioner as a result of this audit. However a re-audit in May 2007 showed that 9% of letters met all five criteria and 15% met none of them. A need has been identifiedfor better referral letters and ways of achieving this were discussed.

In vitro assessment of image-guided otologic surgery: submillimeter accuracy within the region of the temporal bone.

OBJECTIVES: Application of image-guided surgery to otology has been limited by the need for submillimeter accuracy via a fiducial system that is easily usable (noninvasive and nonobstructive). METHODS: A dental bite-block was fitted with a rigid frame with 7 fiducial markers surrounding each external ear. The temporal bones of 3 cadaveric skulls were removed and replaced with surgical targets arranged in a bull's-eye pattern about the centroid of each temporal bone. The surgical targets were identified both within CT scans and in physical space using an infrared optical tracking system. The difference between positions in CT space versus physical space was calculated as target registration error. RESULTS: A total of 234 independent target registration errors were calculated. Mean +/- standard deviation = 0.73 mm +/- 0.25 mm. CONCLUSIONS: These findings show that image-guided otologic surgery with submillimeter accuracy is achievable with a minimally invasive fiducial frame. Significance In vivo validation of the system is ongoing. With such validation, this system may facilitate clinically applicable image-guided otologic surgery. EBM RATING: A.

Maxillary Midline diastema closure after replacement of primary teeth with implant prosthesis.

This case shows an excellent esthetic treatment outcome using implant-retained crowns replacing maxillary laterals and canines in hypodontia patient with unusual incidence of spontaneous diastema closure after the placement of implants. To our knowledge, this is the first case report showing maxillary midline diastema closure after implant placement.

Agreement between clinical measures of quality and patients' rating of fit of existing and new complete dentures.

OBJECTIVES: To assess agreement between patients' appreciation of fit and clinical assessment of quality of existing and new complete dentures. MATERIALS AND METHODS: In each case existing complete dentures at the initial visit and new complete dentures at the first post insertion visit were assessed by a prosthodontist using a validated method for assessing denture quality. Patients rated fit of existing and new complete dentures on four-point scales. Weighted Cohen's kappa and multiple correspondence analyses were the statistical methods employed in this study. RESULTS: 459 patients completed the study. A statistically "fair" level of agreement was found between clinical and patient assessment of dentures. There was close correspondence between dentist and patient appreciation when the existing dentures were rated as poor and when the new dentures were rated highly. DISCUSSION: A worthwhile level of agreement between patients' appreciation of fit of complete dentures and the clinical assessment of quality of existing and new complete dentures was found. Marked differences in the nature of agreement for patients' and clinicians' rating of new and existing dentures were demonstrated. These results emphasize the importance of denture quality in achieving patient approval. CONCLUSION: Agreement and correspondence between patient and clinician appreciation of existing and new complete dentures were determined.

Submillimetric target-registration error using a novel, non-invasive fiducial system for image-guided otologic surgery.

OBJECTIVE: Otologic surgery is undertaken to treat ailments of the ear, including persistent infections, hearing loss, vertigo, and cancer. Typically performed on otherwise-healthy patients in outpatient facilities, the application of image-guided surgery (IGS) has been limited because accurate (<1 mm), non-invasive fiducial systems for otologic surgery have not been available. We now present such a fiducial system. METHODS: A dental bite-block was fitted with a custom-designed rigid frame with 7 fiducial markers surrounding each external ear. The bones containing the ear (i.e., the temporal bones) of 3 cadaveric skulls were removed and replaced with discs containing 13 surgical targets arranged in a cross-hair pattern about the centroid of each ear. The surgical targets (26/skull) and fiducial markers (14/skull) were identified both within CT scans using a published algorithm and in physical space using an infrared optical tracking system. Fiducial registration error (FRE), fiducial localization error (FLE), and target registration error (TRE) were calculated. RESULTS: For all trials, root mean square FRE = 0.66, FLE = 0.72, and TRE = 0.77 mm. The mean TRE for n = 234 independent targets was 0.73 with a standard deviation of 0.25 mm. CONCLUSIONS: Using a novel, non-invasive fiducial system (the EarMark), submillimetric accuracy was repeatably achieved. This system will facilitate image-guided otologic surgery.

Factors affecting survival and usefulness of implants placed in vascularized free composite grafts used in post-head and neck cancer reconstruction.

BACKGROUND: Bone-containing vascularized grafts have been used successfully to reconstruct post-cancer surgical defects. Dental implants can be placed in these bone-containing grafts to allow implant-supported prosthodontic reconstruction of these patients. PURPOSE: The aim of this study was to evaluate the survival of dental implants used in the rehabilitation of subjects treated with bone-containing vascularized grafts to compare usability of implants placed at the time of reconstruction and after healing. MATERIALS AND METHODS: A cross-sectional study was undertaken to examine survival rates of implants placed in vascularized bone-containing grafts either immediately at the time of surgical reconstruction or after 3 months healing. Other factors such as graft type, whether radiation therapy was given, and implant type were recorded. RESULTS: A total of 41 patients had 145 implants placed in 47 vascularized bone-containing flaps. Increased failure rate of implants was seen in immediately placed implants. There was also a significant increase in the number of osseointegrated implants that were prosthodontically unusable or sub-optimally placed in the immediate placement group. Radiation therapy was associated with a significant increase in failure rate. Modern implant surfaces appeared to perform better than machined/turned surfaces. Graft donor site did not influence implant survival. CONCLUSION: This study demonstrated the difficulties encountered with immediate placement of dental implants at the time of post-cancer reconstructive surgery.

Validation of PET imaging by alignment to histology slices.

The aim of this project is to verify the accuracy of positron emission tomography (PET) in identifying the tumour boundary and eventually to enable PET-guided resection with removal of significantly smaller margins. We present a novel use of an image-guided surgery system to enable alignment of preoperative PET images to postoperative histology. The oral cancer patients must have a high resolution CT scan as well as undergoing PET imaging. Registration of these images to the patient during surgery is achieved using a device that attaches to the patient's upper or lower teeth. During the procedure markers are placed around the lesion within tissue that is to be resected. These are marked along with any convenient anatomical landmarks using the image guidance system, providing the location of the points in the preoperative images. After the sample has been resected, slices through at least 3 of these points are made and photographed. Registration should be possible using these landmarks, but the accuracy of alignment is much improved by marking the bone surface in the histology image and registering to preoperative CT.

A preliminary study to investigate the potential of plasma screen technology in small group teaching for dental undergraduates.

AIM: This preliminary study was devised to ascertain whether students considered that they had an adequate view of demonstrated procedures, while observing these directly at the workbench, or indirectly on a remote plasma screen. In addition, this study sought to identify whether the students observing remotely believed that they had been disadvantaged by the inability to question the demonstrator during the demonstration. METHODS: Seventeen students divided into two groups observed a live demonstration of a laboratory technical procedure either at the workbench, or remotely at a plasma screen with the aid of video cameras. They subsequently observed a second demonstration with the roles reversed. Questionnaires were used to obtain the students' views of their ability to see and interact with the demonstrator. RESULTS: The responses of the students observing the demonstration at the plasma screen indicated that (they felt that) they were able to see the demonstration more clearly than those observing at the workbench. Those observing at the plasma screen first, in particular indicated this. The majority of students acknowledged their inability to ask questions while observing at the plasma screen. There was overwhelming support for the idea that the plasma screen should be used to complement the demonstration at the workbench. CONCLUSION: Plasma screen technology has considerable potential as a teaching tool for small groups of students, where it can afford significantly superior views of practical procedures. The students considered that the plasma screen would be best employed to provide close-up views to supplement a live demonstration. When used remotely, the apparatus may be used more satisfactorily if videoconferencing technology is also employed to facilitate interaction with the demonstrator.