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International Journal of... 2007Maxillary molar distalization is an increasingly popular option for the resolution of Class II malocclusions. This study describes the effects of one particular molar...
Role of the friction free distalize appliance (2FDA)PAT in the molar distalization: photoelastic analysis and alkaline-phosphatase (ALP) activity on first molar and bicuspid.
Maxillary molar distalization is an increasingly popular option for the resolution of Class II malocclusions. This study describes the effects of one particular molar distalizing appliance, the Friction Free Distalize Appliance (2FDA), in a sample of 20 consecutively treated and growing patients to verify the osteoblastic activity in the compression and traction sites of both the molars and the bicuspids when used as the anchorage teeth. The 2FDA appliances were constructed utilizing a Nickel Titanium open coil spring of 200 gr force in order to distalize the maxillary first molar. The reaction force was controlled utilizing the principle of low/free friction. The results show that the resin around the root of the bicuspid did not discolour at all, which indicates an absence of a force load. On the other hand, on the molar, the resin around the root of the molar became discoloured due to the fact that an orthodontic force was involved with the tooth. To better understand whether the quantity of force that reached the tooth was able to produce osteoblastic recruitment in the sites of tension of the molar and the bicuspid, we quantified an enzyme, the alkaline phosphatase (ALP), present. This measurement allowed us to verify a regular increase of the ALP on the site of molar traction. We also elaborated a mathematical model to evaluate the quantity of force of reaction that produces the device on the bicuspid. Such force results as being 8.34 grams which equals half the pressure of the capillaries of the parodontal ligament (18 grams). The 2FDA appliance compares favourably with other intra-oral distalization devices for the resolution of patients with Class II malocclusions, and is the only distalizing appliance that does not determine osteoclastic/osteoblastic recruitment on the anchorage tooth.
Topics: Alkaline Phosphatase; Bicuspid; Humans; Malocclusion, Angle Class II; Models, Theoretical; Molar; Orthodontic Appliance Design; Orthodontic Appliances; Osteoblasts; Tooth Movement Techniques
PubMed: 17897504
DOI: 10.1177/039463200702001s13 -
Archives of Oral Biology Jan 2022The aim of the present study was to assess mineralization and trabecular microarchitecture in atrophic edentulous mandibles and to identify regional differences and...
OBJECTIVE
The aim of the present study was to assess mineralization and trabecular microarchitecture in atrophic edentulous mandibles and to identify regional differences and relations with the extent of resorption.
METHODS
Cortical and trabecular bone volumes in anterior, premolar and molar regions of 10 edentulous cadaveric mandibles (5 males and 5 females; mean age ± SD: 85.4 ± 8.3 years) were assessed by microcomputed tomography. Mandibular height and Cawood & Howell classes were recorded. Concerning trabecular volumes, bone mineral density (BMD), bone volume fraction, trabecular tissue volume fraction, connectivity density, trabecular number, trabecular thickness, trabecular separation, degree of anisotropy, and structural model index were measured; concerning cortical volumes porosity, BMD and cortical thickness were measured.
RESULTS
In molar regions, the bone volume fraction and trabecular number were lower, whereas trabecular separation, degree of anisotropy and cortical BMD were higher compared to anterior regions. In premolar regions, mandibular height correlated negatively with trabecular number (Spearman's correlation r = 0.73, p = 0.017) and connectivity density (Spearman's correlation r = 0.82, p = 0.004), and correlated positively with trabecular separation (Spearman's correlation r = - 0.65, p = 0.04). Cortical BMD was higher at bucco-inferior cortex of molar and inferior border of premolar region and lower at anterior cranial buccal and lingual surface.
CONCLUSIONS
In the premolar region, increased resorption coincides with local impairment of trabecular bone quality. Cortical bone BMD is higher in areas with highest strains and lower in areas with most mandibular resorption. Trabecular bone volume and quality is superior in the anterior region of the edentulous mandible, which might explain improved primary stability of dental implants in this region.
Topics: Bicuspid; Bone Density; Female; Humans; Male; Mandible; Molar; X-Ray Microtomography
PubMed: 34773733
DOI: 10.1016/j.archoralbio.2021.105302 -
The Angle Orthodontist Apr 1979A specially-designed force transducer was used to measure lateral resting-tongue pressure in 23 subjects. Seventeen subjects had normal occlusion and six had dental...
A specially-designed force transducer was used to measure lateral resting-tongue pressure in 23 subjects. Seventeen subjects had normal occlusion and six had dental open-bite conditions. Three sensing tips with different contact areas were used to study the relationship between sensor area and measured force. The average force of the resting tongue was 0.8 g when measured with a 4.9 mm diameter sensor (pressure = 0.039 g/mm2). When the size of the sensor tip was increased, the force of the tongue increased in a nonlinear manner. Controlled incremental lingual constrictions of 6 mm resulted in an average increase in lingual force of 230 percent. The mean rate of change, measured in deflection gradient, was 0.34 g/mm. The mean stiffness of the lingual musculature was 2.30 g/mm. A correlation of r = --0.4 was found between resting-tongue pressure and mandibular intercanine width.
Topics: Adolescent; Adult; Bicuspid; Cuspid; Dental Occlusion; Elasticity; Female; Humans; Male; Malocclusion; Manometry; Pressure; Stress, Mechanical; Tongue; Transducers
PubMed: 286570
DOI: 10.1043/0003-3219(1979)049<0092:RTP>2.0.CO;2 -
The Angle Orthodontist 1994The late mixed dentition stage of development, after the eruption of the first premolars, is a favorable time to start treatment to resolve crowding. This protocol... (Review)
Review
The late mixed dentition stage of development, after the eruption of the first premolars, is a favorable time to start treatment to resolve crowding. This protocol offers the clinician choices. If nonextraction treatment is preferable, arch length preservation can provide the space for alignment in approximately 75% of all patients with crowding. If extraction treatment is indicated, the first premolars are available.
Topics: Bicuspid; Dental Arch; Dentition, Mixed; Humans; Incisor; Malocclusion; Mandible; Orthodontics, Corrective; Serial Extraction; Time Factors; Tooth Eruption
PubMed: 7864462
DOI: 10.1043/0003-3219(1994)064<0415:CTOT>2.0.CO;2 -
The Angle Orthodontist Jul 1987Various combinations of orthodontic force, luxation, and observation are applied to 12 teeth traumatically intruded in 3 large dogs. All showed root resorption to some...
Various combinations of orthodontic force, luxation, and observation are applied to 12 teeth traumatically intruded in 3 large dogs. All showed root resorption to some degree. Early orthodontic repositioning, with luxation if immobile, produced the best recovery.
Topics: Animals; Ankylosis; Bicuspid; Dogs; Prognosis; Root Resorption; Tooth Avulsion; Tooth Diseases; Tooth Mobility; Tooth Movement Techniques
PubMed: 3477970
DOI: 10.1043/0003-3219(1987)057<0234:TIT>2.0.CO;2 -
The Journal of Thoracic and... Jun 2020
Commentary: From experience-based surgery toward evidence-based surgery: How can we fill the gap between guidelines and current practice on bicuspid aortic valve-related aortopathy?
Topics: Aortic Valve; Bicuspid; Bicuspid Aortic Valve Disease; Heart Valve Diseases; Humans
PubMed: 31629498
DOI: 10.1016/j.jtcvs.2019.09.035 -
Australian Dental Journal Jun 1998
Topics: Bicuspid; Humans; Mandible; Maxilla; Molar; Syndrome; Tooth, Supernumerary
PubMed: 9707787
DOI: No ID Found -
The Angle Orthodontist May 2021To evaluate the volume, amount, and localization of root resorption in the upper first premolars by micro-computed tomography (micro-CT) after three different rapid...
OBJECTIVES
To evaluate the volume, amount, and localization of root resorption in the upper first premolars by micro-computed tomography (micro-CT) after three different rapid maxillary expansion appliances and two different activation rhythms.
MATERIALS AND METHODS
The patients were divided into three groups; Hyrax, acrylic cap splint (ACS), and full coverage acrylic bonded (FCAB) appliances. Each group was then divided into the following two subgroups: rapid maxillary expansion (RME) and semirapid maxillary expansion (SRME). After expansion was completed, the appliances were stabilized for 12 weeks during the retention period. For each group, 10 premolars (for a total of 60 premolars) were scanned with the micro-CT (SkyScan). The reconstructed 3D images of each root sample were divided into six regions. The resorption craters on these six different root surfaces were analyzed by special CTAn (SkyScan) software for direct volumetric measurements. Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests were used for statistical analysis.
RESULTS
The total volume of root resorption was less with FCAB than with ACS and Hyrax (P < .001). In all groups, a greater volume of resorption was found on the buccal surface than on the lingual surface (P < .001). No significant differences were found between the RME and SRME groups (P > .05).
CONCLUSIONS
All expansion appliances caused root resorption in the upper first premolar teeth, but FCAB may be safer in terms of root resorption. The resorption craters were generally concentrated on the buccal surface. There was no effect of activation rhythm on root resorption.
Topics: Bicuspid; Dental Cementum; Humans; Palatal Expansion Technique; Root Resorption; X-Ray Microtomography
PubMed: 33492378
DOI: 10.2319/052220-465.1 -
JACC. Cardiovascular Interventions Sep 2019
Topics: Aortic Valve; Aortic Valve Stenosis; Bicuspid; Heart Valve Prosthesis; Humans; Treatment Outcome
PubMed: 31537281
DOI: 10.1016/j.jcin.2019.07.007 -
The Angle Orthodontist Jan 2024To compare four first premolar extraction and nonextraction treatment effects on intra-arch width, profile, treatment duration, occlusal outcomes, smile aesthetics and... (Meta-Analysis)
Meta-Analysis
OBJECTIVES
To compare four first premolar extraction and nonextraction treatment effects on intra-arch width, profile, treatment duration, occlusal outcomes, smile aesthetics and stability.
MATERIALS AND METHODS
An electronic search of the literature to June 2, 2023 was conducted using health science databases, with additional search of gray literature, unpublished material, and hand searching, for studies reporting nonsurgical patients with fixed appliances regarding sixteen sub-outcomes. Data extraction used customized forms, quality assessed with ROBINS-I (Risk Of Bias In Non-randomized Studies-of Interventions) and Cochrane RoB 2 (risk-of-bias) tool. GRADE (Grading of Recommendations Assessment, Development and Evaluation) assessed certainty of evidence.
RESULTS
Thirty (29 retrospective studies, 1 randomized controlled trial) studies were included. Random-effect meta-analysis (95% CI) demonstrated maxillary (MD: -2.03 mm; [-2.97, -1.09]; P < .0001) and mandibular inter-first molar width decrease (MD: -2.00 mm; [-2.71, -1.30]; P < .00001) with four first premolar extraction; mandibular intercanine width increase (MD: 0.68 mm; [0.36, 0.99]; P < .0001) and shorter treatment duration (MD: 0.36 years; [0.10, 0.62]; P = .007) in the nonextraction group. Narrative synthesis included three and five studies for upper and lower lip-E plane, respectively. For American Board of Orthodontics Objective Grading System and maxillary/mandibular anterior alignment (Little's irregularity index), each included two studies with inconclusive evidence. There were no eligible studies for UK Peer Assessment Rating (PAR) score. Class I subgroup/sensitivity analyses favored the same results. Prediction interval indicated no significant difference for all outcomes.
CONCLUSIONS
Four first premolar extraction results in maxillary and mandibular inter-first molar width decrease and retraction of upper/lower lips. Nonextraction treatment results in mandibular intercanine width increase and shorter treatment duration. There was no significant difference between the two groups regarding maxillary intercanine width, US PAR score, and posttreatment smile esthetics. Further high-quality focused research is recommended.
Topics: Humans; Orthodontics, Corrective; Retrospective Studies; Tooth Extraction; Esthetics, Dental; Bicuspid
PubMed: 37899069
DOI: 10.2319/021123-98.1