Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, Jan 6, 2014
Obesity is a major risk factor towards the development of obstructive sleep apnea, while signific... more Obesity is a major risk factor towards the development of obstructive sleep apnea, while significant weight loss (both conservatively managed and surgically assisted) has a variable effect upon its severity. Differences in the effect of weight loss on obstructive sleep apnea may be due to underlying craniofacial characteristics. To determine whether craniofacial characteristics can predict OSA treatment response to significant weight loss. We analyzed craniofacial measurements from lateral cephalograms performed at baseline on 57 patients enrolled in a previously reported 2-year randomized clinical weight loss trial (laparoscopic adjustable gastric band surgery versus conservatively [dietician and very low calorie diet] treated). Group mean weight loss was ∼ 13% (mean weight loss 131 to 114 kg), with corresponding reduction in mean apnea hypopnea index (AHI) from 61 to 41 events/h. Computer assisted lateral cephalogram analysis was undertaken by three trained staff blinded to treatm...
Reports of irreversible alteration in jaw posture and destructive occlusal contact relationships ... more Reports of irreversible alteration in jaw posture and destructive occlusal contact relationships in individuals using mandibular advancement devices for obstructive sleep apnea are beginning to appear. This study sought cephalometric means of identifying such individuals before commencing therapy. Cephalograms of 34 obstructive sleep apnea sufferers who had worn mandibular advancement devices for 2 years were compared retrospectively with baseline films taken at commencement of therapy and analyzed for signs of morphologic changes in jaw position and occlusal relationship. In affected patients, two distinct morphologic species of mandibular reposturing became evident: (1) bilateral posterior open bite with destructive incisal attrition; and (2) less destructive intermediate open bite over the premolar and first molar regions. From the observed morphology patterns, gonial angle and maxillary-mandibular plane angle were analyzed as possible vertical cephalometric risk predictors, with...
Implant-supported prostheses must be able to withstand the load capabilities of individual patien... more Implant-supported prostheses must be able to withstand the load capabilities of individual patients to overload them. The gold alloy screw in the Brånemark system is by intention the weakest component. Therefore, if cantilever lengths can be designed so that occlusal forces distributed to individual fixtures are limited to the gold screws' ability to accept them, breakage-free performance may be assured. Models, such as that of Skalak, are capable of developing the required analytical processes to provide the information necessary to achieve this design. Unfortunately, the overt mathematical complexity of the Skalak model has militated against its routine use in the operatory. Its computational aspects are, however, eminently suited to computerization and indeed provide the basis for the computer program that is described in this article. This program is simple to apply clinically and, when used in conjunction with available load parameters of gold screw performance, can provide the clinician with a routine and scientific basis for rational implant prosthesis design.
Although the myofascial pain dysfunction syndrome has a multiple aetiology, faulty vertical dimen... more Although the myofascial pain dysfunction syndrome has a multiple aetiology, faulty vertical dimension is a frequent cause of muscular pain among wearers of full dentures. Furthermore, it has been found that the restoration of a physiological free-way space in such cases, using a method which is based upon cephalometric analysis of the gonial angle, often leads to a dramatic remission of pain. The present investigation was prompted by curiosity as to what the underlying algogenic mechanisms in these cases might be; and how a change in the vertical dimension should so modify them as to result in the disappearance of the pain symptoms. The study is necessarily of a speculative nature, and makes use of two representative cases, one of which was adjudged to have too little free-way, and the other too much. Principles of neuromuscular physiology are applied in attempting to explain the clinical phenomena involved, as well as to find a reason for certain electro-myographic artefacts noted in one of the cases, which would appear to call into question the notion that muscular hyperactivity, per se, is responsible for muscular pain. Potgieter, Monteith & Kemp (1983) have presented an hypothesis that the amount of free-way space present in an individual is an expression of the contractile power of the masseter and medial pterygoid muscles. They have also devised a method whereby, through cephalometric analysis, the optimal amount of free-way may be determined for an edentulous patient during denture construction. Furthermore, they have stated that their method has proved particularly effective in the treatment of denture-wearers presenting with symptoms of the myofascial pain dysfunction syndrome. However, in the light of this syndrome's multifactorial aetiology one must assume that only those symptoms which are related to a faulty free-way space are at issue. The purpose of the present investigation is to examine the latter assertion; and by the application of the suggested method of cephalometric analysis to two representative cases, attempt to explain the phenomenon in terms of neuromuscular mechanisms. Of the two cases to be examined, one was found to have too much free-way, while the other had been provided with too little. Both had presented with symptoms of severe muscle pain.
This study was prompted by the hypothesis that the contractile power of the masseter and medial p... more This study was prompted by the hypothesis that the contractile power of the masseter and medial pterygoid muscles influences not only the shape of the gonial angle of the mandible into which these muscles insert, but also that they play a major part in determining the amount of free-way space present in any individual. Tracings were made from the lateral cephalograms of 130 dentate subjects and the gonial angle measured in each case. Free-way space was also measured, using a dakometer, and the paired values subjected to statistical analysis. A strong inverse correlation was found to exist, indicating that throughout the sample a decrease (or sharpening) of the gonial angle is accompanied by a predictable increase in the free-way space. By applying the processes of linear regression to the paired results, a formula was obtained which may be used to predict the best value of one variable for any given value of the other. Thus, in an edentulous case, where the value of the free-way space measurement is unknown, a method is provided for predicting its best value by the determination of the patient's gonial angle through cephalometric analysis.
Bitewing radiographs are widely used to detect caries on the approximal surfaces of teeth. The ai... more Bitewing radiographs are widely used to detect caries on the approximal surfaces of teeth. The aim of this study was to determine the prevalence of approximal caries in an educated young adult (New Zealand dental student) population, and to compare the diagnostic decisions of students and university teachers. A total of 123 students aged from 18 to 25 years (mean age 21 years) participated, having given their informed consent. Their bitewings were digitised and assessed for approximal carious lesions from the distal surface of the first premolars to the mesial surface of the second molars on the same computer screen. The following criteria were used: (0) no detectable radiolucency, (R1) lesion confined to the outer half of the enamel, (R2) lesion into the inner half of the enamel, (R3) lesion into the outer half of dentine along the amelodentinal junction, (R4) lesion beyond the outer part of the dentine. The views were assessed by two final-year dental students and two experienced ...
To compare a monotherapy of Er:YAG laser debridement (ERL), wavelength 2940 nm, with mechanical s... more To compare a monotherapy of Er:YAG laser debridement (ERL), wavelength 2940 nm, with mechanical scaling and root planing (SRP) for the treatment of chronic periodontitis using clinical and patient-centred outcomes. Twenty-eight participants had two randomly assigned quadrants treated with ERL and two with SRP. Full-mouth plaque index, probing depth, bleeding on probing, clinical attachment level and gingival recession were recorded at baseline and 6- and 12-weeks post therapy. A questionnaire was used to assess pain, discomfort and satisfaction during and after treatment. Twenty-two participants completed treatment and had 6- and 12-week clinical re-evaluations. SRP provided greater mean pocket depth reduction at 6- and 12-weeks (p = 0.01 and p = 0.003 respectively), and a greater reduction in pockets ≥ 4 mm at 6 weeks only (p = 0.03) compared with ERL. SRP also resulted in a significant reduction in bleeding on probing (BOP) sites at 12 weeks compared with ERL and a statistically significant greater reduction in mean clinical attachment level (CAL) at 6- (p = 0.02) and 12-weeks (p = 0.03). Patients expressed greater satisfaction with SRP on the day of treatment but were equally satisfied subsequently. SRP resulted in a statistically significant greater short-term improvement in clinical parameters and patient satisfaction compared with ERL.
To: (i) study coronal pulp dimensions in human first molar teeth; (ii) investigate the effects of... more To: (i) study coronal pulp dimensions in human first molar teeth; (ii) investigate the effects of restorations on pulp size; (iii) determine differences in dimensions between teeth of Mongoloid patients and teeth of other ethnic groups; and (iv) record the presence of pulp stones. Bitewing radiographs of 121 subjects (mean age, 20.9 years) were taken under standardized conditions. The films were digitally scanned and nine measurements were made from the image of each first molar. The data were analysed in terms of presence or absence of restorations and in terms of racial group. Differences were examined using Student's t-test, Pearson correlations and Levene's test. A total of 445 teeth were analysed. Large crowns were correlated to large pulps. Teeth restored with occlusal and proximal restorations had significantly smaller pulps (P = 0.044 and 0.004, respectively), but no difference was found in pulp area in the clinical crown between the restoration types. Mongoloid crowns were shorter and more bulbous. Pulp areas of maxillary molars and pulp widths at the cervix of mandibular molars were significantly larger in Mongoloids. The pulp area in the clinical crown correlated to pulp horn height for Mongoloids and others and for maxillary and mandibular teeth. No differences were found between the heights of pulp horns in the Mongoloid and other teeth. Four of the pulp measurements demonstrated sexual dimorphism. Stones were present in almost 10% of the subjects, representing 4% of the tooth pulps examined. Even teeth with shallow occlusal restorations had reduced pulp spaces. There were significant differences in pulp and crown dimensions between the teeth of Mongoloid patients and those of other patients.
The European journal of prosthodontics and restorative dentistry
The aim was to determine whether extracted teeth could be used to test the Prepometer instrument,... more The aim was to determine whether extracted teeth could be used to test the Prepometer instrument, which indicates pulp proximity with green/amber/red light emitting diodes. Third molars were reduced to a plane in dentine and Prepometer readings made. Dentine was removed in 0.5 mm increments and readings made until only lights 9 or 10 (red) showed. The teeth were sectioned and the dentine thickness measured. Analysis permitted construction of a highly significant predictor-model (p < 0.01), the red/amber light boundary coinciding with a dentine thickness of 2.4 mm. The Prepometer was consistent in predicting pulp proximity but was more sensitive than specified.
Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, Jan 6, 2014
Obesity is a major risk factor towards the development of obstructive sleep apnea, while signific... more Obesity is a major risk factor towards the development of obstructive sleep apnea, while significant weight loss (both conservatively managed and surgically assisted) has a variable effect upon its severity. Differences in the effect of weight loss on obstructive sleep apnea may be due to underlying craniofacial characteristics. To determine whether craniofacial characteristics can predict OSA treatment response to significant weight loss. We analyzed craniofacial measurements from lateral cephalograms performed at baseline on 57 patients enrolled in a previously reported 2-year randomized clinical weight loss trial (laparoscopic adjustable gastric band surgery versus conservatively [dietician and very low calorie diet] treated). Group mean weight loss was ∼ 13% (mean weight loss 131 to 114 kg), with corresponding reduction in mean apnea hypopnea index (AHI) from 61 to 41 events/h. Computer assisted lateral cephalogram analysis was undertaken by three trained staff blinded to treatm...
Reports of irreversible alteration in jaw posture and destructive occlusal contact relationships ... more Reports of irreversible alteration in jaw posture and destructive occlusal contact relationships in individuals using mandibular advancement devices for obstructive sleep apnea are beginning to appear. This study sought cephalometric means of identifying such individuals before commencing therapy. Cephalograms of 34 obstructive sleep apnea sufferers who had worn mandibular advancement devices for 2 years were compared retrospectively with baseline films taken at commencement of therapy and analyzed for signs of morphologic changes in jaw position and occlusal relationship. In affected patients, two distinct morphologic species of mandibular reposturing became evident: (1) bilateral posterior open bite with destructive incisal attrition; and (2) less destructive intermediate open bite over the premolar and first molar regions. From the observed morphology patterns, gonial angle and maxillary-mandibular plane angle were analyzed as possible vertical cephalometric risk predictors, with...
Implant-supported prostheses must be able to withstand the load capabilities of individual patien... more Implant-supported prostheses must be able to withstand the load capabilities of individual patients to overload them. The gold alloy screw in the Brånemark system is by intention the weakest component. Therefore, if cantilever lengths can be designed so that occlusal forces distributed to individual fixtures are limited to the gold screws&#39; ability to accept them, breakage-free performance may be assured. Models, such as that of Skalak, are capable of developing the required analytical processes to provide the information necessary to achieve this design. Unfortunately, the overt mathematical complexity of the Skalak model has militated against its routine use in the operatory. Its computational aspects are, however, eminently suited to computerization and indeed provide the basis for the computer program that is described in this article. This program is simple to apply clinically and, when used in conjunction with available load parameters of gold screw performance, can provide the clinician with a routine and scientific basis for rational implant prosthesis design.
Although the myofascial pain dysfunction syndrome has a multiple aetiology, faulty vertical dimen... more Although the myofascial pain dysfunction syndrome has a multiple aetiology, faulty vertical dimension is a frequent cause of muscular pain among wearers of full dentures. Furthermore, it has been found that the restoration of a physiological free-way space in such cases, using a method which is based upon cephalometric analysis of the gonial angle, often leads to a dramatic remission of pain. The present investigation was prompted by curiosity as to what the underlying algogenic mechanisms in these cases might be; and how a change in the vertical dimension should so modify them as to result in the disappearance of the pain symptoms. The study is necessarily of a speculative nature, and makes use of two representative cases, one of which was adjudged to have too little free-way, and the other too much. Principles of neuromuscular physiology are applied in attempting to explain the clinical phenomena involved, as well as to find a reason for certain electro-myographic artefacts noted in one of the cases, which would appear to call into question the notion that muscular hyperactivity, per se, is responsible for muscular pain. Potgieter, Monteith &amp; Kemp (1983) have presented an hypothesis that the amount of free-way space present in an individual is an expression of the contractile power of the masseter and medial pterygoid muscles. They have also devised a method whereby, through cephalometric analysis, the optimal amount of free-way may be determined for an edentulous patient during denture construction. Furthermore, they have stated that their method has proved particularly effective in the treatment of denture-wearers presenting with symptoms of the myofascial pain dysfunction syndrome. However, in the light of this syndrome&#39;s multifactorial aetiology one must assume that only those symptoms which are related to a faulty free-way space are at issue. The purpose of the present investigation is to examine the latter assertion; and by the application of the suggested method of cephalometric analysis to two representative cases, attempt to explain the phenomenon in terms of neuromuscular mechanisms. Of the two cases to be examined, one was found to have too much free-way, while the other had been provided with too little. Both had presented with symptoms of severe muscle pain.
This study was prompted by the hypothesis that the contractile power of the masseter and medial p... more This study was prompted by the hypothesis that the contractile power of the masseter and medial pterygoid muscles influences not only the shape of the gonial angle of the mandible into which these muscles insert, but also that they play a major part in determining the amount of free-way space present in any individual. Tracings were made from the lateral cephalograms of 130 dentate subjects and the gonial angle measured in each case. Free-way space was also measured, using a dakometer, and the paired values subjected to statistical analysis. A strong inverse correlation was found to exist, indicating that throughout the sample a decrease (or sharpening) of the gonial angle is accompanied by a predictable increase in the free-way space. By applying the processes of linear regression to the paired results, a formula was obtained which may be used to predict the best value of one variable for any given value of the other. Thus, in an edentulous case, where the value of the free-way space measurement is unknown, a method is provided for predicting its best value by the determination of the patient&#39;s gonial angle through cephalometric analysis.
Bitewing radiographs are widely used to detect caries on the approximal surfaces of teeth. The ai... more Bitewing radiographs are widely used to detect caries on the approximal surfaces of teeth. The aim of this study was to determine the prevalence of approximal caries in an educated young adult (New Zealand dental student) population, and to compare the diagnostic decisions of students and university teachers. A total of 123 students aged from 18 to 25 years (mean age 21 years) participated, having given their informed consent. Their bitewings were digitised and assessed for approximal carious lesions from the distal surface of the first premolars to the mesial surface of the second molars on the same computer screen. The following criteria were used: (0) no detectable radiolucency, (R1) lesion confined to the outer half of the enamel, (R2) lesion into the inner half of the enamel, (R3) lesion into the outer half of dentine along the amelodentinal junction, (R4) lesion beyond the outer part of the dentine. The views were assessed by two final-year dental students and two experienced ...
To compare a monotherapy of Er:YAG laser debridement (ERL), wavelength 2940 nm, with mechanical s... more To compare a monotherapy of Er:YAG laser debridement (ERL), wavelength 2940 nm, with mechanical scaling and root planing (SRP) for the treatment of chronic periodontitis using clinical and patient-centred outcomes. Twenty-eight participants had two randomly assigned quadrants treated with ERL and two with SRP. Full-mouth plaque index, probing depth, bleeding on probing, clinical attachment level and gingival recession were recorded at baseline and 6- and 12-weeks post therapy. A questionnaire was used to assess pain, discomfort and satisfaction during and after treatment. Twenty-two participants completed treatment and had 6- and 12-week clinical re-evaluations. SRP provided greater mean pocket depth reduction at 6- and 12-weeks (p = 0.01 and p = 0.003 respectively), and a greater reduction in pockets ≥ 4 mm at 6 weeks only (p = 0.03) compared with ERL. SRP also resulted in a significant reduction in bleeding on probing (BOP) sites at 12 weeks compared with ERL and a statistically significant greater reduction in mean clinical attachment level (CAL) at 6- (p = 0.02) and 12-weeks (p = 0.03). Patients expressed greater satisfaction with SRP on the day of treatment but were equally satisfied subsequently. SRP resulted in a statistically significant greater short-term improvement in clinical parameters and patient satisfaction compared with ERL.
To: (i) study coronal pulp dimensions in human first molar teeth; (ii) investigate the effects of... more To: (i) study coronal pulp dimensions in human first molar teeth; (ii) investigate the effects of restorations on pulp size; (iii) determine differences in dimensions between teeth of Mongoloid patients and teeth of other ethnic groups; and (iv) record the presence of pulp stones. Bitewing radiographs of 121 subjects (mean age, 20.9 years) were taken under standardized conditions. The films were digitally scanned and nine measurements were made from the image of each first molar. The data were analysed in terms of presence or absence of restorations and in terms of racial group. Differences were examined using Student&#39;s t-test, Pearson correlations and Levene&#39;s test. A total of 445 teeth were analysed. Large crowns were correlated to large pulps. Teeth restored with occlusal and proximal restorations had significantly smaller pulps (P = 0.044 and 0.004, respectively), but no difference was found in pulp area in the clinical crown between the restoration types. Mongoloid crowns were shorter and more bulbous. Pulp areas of maxillary molars and pulp widths at the cervix of mandibular molars were significantly larger in Mongoloids. The pulp area in the clinical crown correlated to pulp horn height for Mongoloids and others and for maxillary and mandibular teeth. No differences were found between the heights of pulp horns in the Mongoloid and other teeth. Four of the pulp measurements demonstrated sexual dimorphism. Stones were present in almost 10% of the subjects, representing 4% of the tooth pulps examined. Even teeth with shallow occlusal restorations had reduced pulp spaces. There were significant differences in pulp and crown dimensions between the teeth of Mongoloid patients and those of other patients.
The European journal of prosthodontics and restorative dentistry
The aim was to determine whether extracted teeth could be used to test the Prepometer instrument,... more The aim was to determine whether extracted teeth could be used to test the Prepometer instrument, which indicates pulp proximity with green/amber/red light emitting diodes. Third molars were reduced to a plane in dentine and Prepometer readings made. Dentine was removed in 0.5 mm increments and readings made until only lights 9 or 10 (red) showed. The teeth were sectioned and the dentine thickness measured. Analysis permitted construction of a highly significant predictor-model (p < 0.01), the red/amber light boundary coinciding with a dentine thickness of 2.4 mm. The Prepometer was consistent in predicting pulp proximity but was more sensitive than specified.
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