Canine Transposition - Prevalence, Distribution and Treatment Considerations among Orthodontic Patients.

Tooth transposition is a relatively rare dental anomaly of interchange in position of two adjacent teeth. AIM: To determine the prevalence and distribution of canine transposition in a sample of orthodontic patients and present treatment alternatives and outcome. STUDY DESIGN: The records of 3000 consecutively treated orthodontic patients from a university clinic were surveyed to detect canine transposition in both dental arches. The data was recorded according to gender, age, number and location. RESULTS: Canine transpositions were detected in 15 subjects, 3 (20%) males and 12 (80%) females presenting a prevalence of 0.5%. Of them, 6 were between the maxillary canine and first premolar, 7 between the maxillary canine and lateral incisor, 2 transpositions were between the mandibular canine and the lateral incisor. A female to male ratio of 4:1 with left side predominance was found. Treatment options include extracting the transposed teeth, maintaining them in their transposed position, or repositioning them in their normal place within the dental arch. CONCLUSION: The prevalence of canine transposition in the present sample was found to be 0.5% with a greater frequency in the maxilla. Treatment options include extraction of one of the transposed teeth, alignment of the teeth in their transposed position or correction of the anomaly. The latter gives the best esthetic outcome.

The use of Bjork's indications of growth for evaluation of extremes of skeletal morphology.

BACKROUND: Morphological indicators within the cranium for prediction of mandibular growth patterns as reported by Bjork are: (1) inclination of the condylar head (ICH), (2) curvature of mandibular canal (CMC), (3) shape of the lower border of the mandible and specifically depth of the antegonial notch (AN), (4) inclination of the symphysis (ISY), (5) interincisal angle (IIA), (6) intermolar angle (IMA), and (7) lower anterior face height (LAFH). The purpose of this study was to examine the association of these indicators as they relate to extreme skeletal patterns observed in skeletally mature subjects. MATERIALS: The pre-treatment lateral cephalometric radiographs of 395 post-growth subjects were randomly selected from the archives of a university orthodontic department. These were divided in three groups according to their MP-SN angle [normal: 28-36degrees (G1), hypodivergent: ≤26degrees (G2), hyperdivergent: ≥38degrees (G3)]. RESULTS: It was found that only LAFH was correlated to age across all groups. However, within G1, G2, and G3, and between genders, it was found that there were statistically significant differences for all indicators in relation to age, except IMA (P > 0.05). In addition, ISY and IMA had a predictive value lower than the chance level (0.5). CONCLUSION: Bjork's implant studies have contributed much to understanding facial-skeletal growth; however, this study suggests that their utilization as a tool in classifying extreme skeletal patterns requires careful evaluation of all the parameters involved.

Long- and short-term effects of headgear traction with and without the maxillary second molars.

INTRODUCTION: A quantitative assessment of maxillary first molar distalization with and without the maxillary second molar (M2) was carried out. METHODS: Fifty-six cervical headgear patients undergoing fixed appliance orthodontic treatment were divided into 2 groups: before (G - M2) and after (G + M2) eruption of the maxillary second molars (ages, 11.87 ± 1.20, and 13.05 ± 1.55 years, respectively). The tightness of the dental contact point (TDCP) and the space between the second premolar and the maxillary first molar were measured at 6 levels of headgear force (0-15 N) at 3 intervals 6 months apart (T0, T1, T2). RESULTS: Relationships were found between space and TDCP, time, and presence or absence of the maxillary second molar at T1 and T2 (P <0.001). The TDCP decreased and space increased with increase in initial headgear force. An increase in initial force beyond 6 to 9 N did not significantly increase the initial maxillary first molar distalization. The G - M2 TDCP and space measurements were similar to those of G + M2 at T2 with the eruption of the maxillary second molar. From T0 to T1, maxillary first molar distalization was greater in G - M2. In comparison with our previous headgear-alone study, initial distalization with a fully bonded appliance was reduced by 4-fold. CONCLUSIONS: Headgear therapy is more effective before the eruption of the maxillary second molar. Once it erupts, the distalization pace of the maxillary first molar is reduced, but it can nevertheless be pursued at a slower pace when the maxillary second molar is present.

Effects of Class II elastics during growth on the functional occlusal plane according to skeletal pattern and extraction vs nonextraction.

OBJECTIVES: To investigate the effect of Class II intermaxillary elastics on the functional occlusal plane (FOP) of growing patients. MATERIALS AND METHODS: A total of 50 participants aged 11 to 16 years were selected from a university clinic archive >1-year after treatment and after undergoing 6 months of Class II elastic wear, taking pretreatment (T0) and posttreatment (T1) lateral cephalometric radiographs, and consenting to participate at recall (T2). Participants were divided into 3 groups according to skeletal pattern or into 2 groups according to treatment with extraction (E) or nonextraction (NE). Angular changes of FOP relative to the Sella-Nasion (SN), mandibular plane (MP), and Frankfort horizontal (FH) were compared within and between groups. RESULTS: A statistically significant reduction of FOP-SN/FH, but not of FOP-MP, was found from T0-T1-T2 when all patients were grouped together. FOP-SN/MP/FH was significantly the largest in the patients with a hyperdivergent skeletal pattern, but lowest in the patients with a hypodivergent skeletal pattern at T0, T1, and T2 (P < .032). FOP-MP at T0-T2 was statistically larger in group E than in group NE (P < .02). No differences were found for FOP changes (change before treatment minus after treatment and change after treatment minus 1 year after treatment) between different skeletal patterns (P > .433) and treatment groups (P > .193). CONCLUSIONS: Use of Class II elastics during the growth period was not found to show adverse effects on FOP rotation. Neither skeletal pattern nor treatment modality differed in the response to Class II elastics with regard to FOP changes. Individual patient growth pattern must be taken into consideration when treatment planning the use of Class II elastics. Orthodontists should take into account individual skeletal and growth patterns while using Class II elastics.

Influence of Practitioner-Related Placement Variables on the Compressive Properties of Bulk-Fill Composite Resins-An In Vitro Clinical Simulation Study.

Aims: To determine if restoration location and/or execution behavior force parameters have an influence on the mechanical properties of bulk-fill composite dental restorations. Methods: Pressure transducers were placed within each quadrant of dental mannequin jaws. Cylindrical molds were placed above the transducers and filled with two bulk-fill composite materials, Filtek and Tetric, by four experienced dentists. Each dentist prepared five specimens per quadrant and material. The total placement time, mean force, number of peak forces (above 25 N), and mean peak(s) force during placement were measured. Then, the stiffness and maximal compressive strength of the specimens were determined while loading the specimens up to failure using a universal loading machine. Results: Placement time was affected by jaw (p < 0.004) and side (p < 0.029), with the shortest time demonstrated for the left side of the mandible. Force exerted during restoration placement was not normally distributed without differences in location (jaw) or material. A higher application force was found on the right side (p < 0.01). The number of peak forces was affected by side (p < 0.03), with less peaks on the left side. No significant differences were found in compressive strength when correlated to restoration location, participant, or material (p = 0.431). The stiffness values of Filtek (3729 ± 228 N/mm) were found to be 15% higher than Tetric (3248 ± 227 N/mm) (p < 0.005). No correlations were found between the compressive strength or stiffness and the amount of force applied during placement. Conclusions: The individual restoration material placement parameters did influence practitioner performance; however, these differences did not affect the mechanical properties of the final restoration.

The Impact of the COVID-19 Pandemic on Israeli Orthodontic Practice: A Clinic's Activity and Patients' Attitudes.

The current study aimed to characterize the activity in orthodontic clinics during the COVID-19-induced lockdown and the inter-lockdown periods, as well as to evaluate patients' perspectives with respect to their fears, their extent of cooperation with treatment, and their emergency needs during the lockdown. The data were gathered from 11 private orthodontic clinics from 1 January 2020 to 8 March 2021, which included three lockdowns and inter-lockdowns. Information specifying the number of admissions, missed appointments, and emergency visits was gathered. Four hundred and twenty-nine orthodontic patients treated in those clinics agreed to complete a questionnaire that evaluated their concerns and expectations, the treatment emergency issues, implementation of the orthodontist's instructions, and contact with the clinical staff during lockdowns. There was a significant increase in the number of scheduled appointments during the inter-lockdown periods, compared with the pre-pandemic period (p = 0.001). No difference in the number of missed/canceled or emergency appointments was found between the different periods (p > 0.420). The majority (89.6%) of the emergency visits involved issues with appliances; 68.7% of the subjects were advised to present themselves at clinics. During the peaks of the waves of the COVID-19 pandemic, a sharp rise in the number of missed and urgent appointments was not found. Reducing the number of orthodontic emergencies may assist in reducing patient fears.

Assessing Children's Dental Age with Panoramic Radiographs.

(1) Background: The aim of the study was to assess the dental age of the subjects and compare it to their chronological age; to assess the dominant tooth for evaluation of dental age; and to investigate possible individual differences between the left and right side of the dental arch. (2) Methods: This study involved evaluating panoramic radiographs of patients aged 7-13 years. A separate assessment was performed for each tooth according to the degree of germ development. Each subject's dental age was estimated. (3) Results: The study involved evaluating 349 panoramic radiographs. No difference was found between stages of tooth development on the right side and left side. Correlation between the stages of tooth development and the chronological age was found to be highest in the second permanent molar teeth. The age can be predicted with the estimated age of tooth #37 and the gender of the patient. (4) Conclusions: The chronological age of children aged 7-13 may be estimated based on a modified seven-stage London Atlas of tooth development, where the most accurate landmark(s) of use are second molars.

Dental Anomalies' Characteristics.

The aim of this study was to characterize dental anomalies. The pretreatment records (photographs and radiographs) of 2897 patients (41.4% males and 58.6% females) were utilized to detect dental anomalies. The dental anomalies studied were related to number, size and shape, position, and eruption. A Chi-square test was carried out to detect associations between dental anomalies, jaw, and sex. A total of 1041 (36%) of the subjects manifested at least one dental anomaly. The prevalence of all dental anomalies was jaw-dependent and greater in the maxilla, except for submerged and transmigrated teeth. The most frequently missing teeth were the maxillary lateral incisor (62.3%) and the mandibular second premolars (60.6%). The most frequent supernumerary teeth were the incisors in the maxilla (97%) and the first premolars in the mandible (43%). Dental anomalies are more frequent in the maxilla and mainly involve the anterior teeth; in the mandible, however, it is the posterior teeth. These differences can be attributed to the evolutionary history of the jaws and their diverse development patterns.

Duration of elastomeric separation and effect on interproximal contact point characteristics.

INTRODUCTION: The common protocol of a week-long duration of elastomeric separators to facilitate band placement usually causes discomfort. In this study, we examined the minimum separation time required to create an interproximal space >0.16 mm (band thickness), the interproximal changes over 24 hours after separator removal, and the mechanical characteristics of various separators. METHODS: Thirty subjects, ages 28.1 +/- 2.8 years, had an elastomeric separator placed between the mandibular second premolar and first molar (CP5-6) for 1, 4, 12, and 24 hours. After separator removal, CP5-6 was measured for space and tightness of dental contact point (TDCP) changes up to 24 hours after separator removal. The mechanical behaviors of 6 manufacturers' separators were compared. RESULTS: After 12 and 24 hours of separation, all patients demonstrated space >0.16 mm (P <.001). A significant negative correlation (R = -0.59 to -0.63; P = .001) was found between baseline TDCP and the space measured at separator removal. A biphasic viscoelastic recovery (82%-95%) to baseline tightness level occurred within 24 hours. Variation between manufacturers was low (9%). CONCLUSIONS: Separators should be placed a day before banding. The patient should arrive 3 to 4 hours before the appointment for separator replacement if the separator is lost. Rapid recovery after separation removal implies the biological soundness of elastomeric separation regardless of the manufacturer used.

Duration and anchorage management of canine retraction with bodily versus tipping mechanics.

OBJECTIVE: To compare tipping mechanics (TM) and bodily mechanics (BM) with respect to duration, angulation, and anchorage loss during canine retraction. MATERIALS AND METHODS: TM and BM brackets were bonded to the upper right and left canines, respectively, of 14 subjects requiring maxillary first premolar extractions. The upper canines were retracted with variable nickel titanium closed coil springs (F = 0.50 or 0.75 N) attached posteriorly to a Nance anchorage appliance through the first molars. Panoramic radiographs and dental casts were taken at five time points. Canine angulation was assessed with custom metallic jigs inserted into the vertical slots of the canine brackets prior to radiographic exposure. RESULTS: The canine crown contacted the second premolar after 102.2 +/- 106 and 99.0 +/- 80.0 days, and achieved root uprighting in 72.0 +/- 31.3 and 37.2 +/- 42.7 additional days with the TM and BM groups, respectively. Only the uprighting stage differed significantly between the two mechanics (P < .05). During retraction, tooth angulation differed significantly (P < .001) between the TM (6 degrees ) and BM (-0.8 degrees ) groups. Anchorage loss, as assessed by mesial molar movement, was 1.2 +/- 0.3 mm and 1.4 +/- 0.5 mm for the TM and BM groups, respectively. CONCLUSIONS: Bodily canine retraction occurred faster (38 days) than tipping due to a shorter duration of root uprighting. Anchorage loss (17%-20%) was similar for both retraction methods, ie, maximum anchorage could not be provided by the Nance appliance. Both TM and BM brackets had inadequate rotational control of the retracted canine.

Bracket placement in lingual vs labial systems and direct vs indirect bonding.

OBJECTIVE: To examine the ultimate accuracy of bracket placement in labial vs lingual systems and in direct vs indirect bonding techniques. MATERIALS AND METHODS: Forty pretreatment dental casts of 20 subjects were selected. For each dental cast, four types of bracket placement were compared: labial direct (LbD), labial indirect (LbI), lingual direct (LgD), and lingual indirect (LgI). Direct bonding was performed with the casts held in a mannequin head. Labial brackets were oriented with a Boone gauge, and lingual brackets were oriented with the Lingual-Bracket-Jig System. Torque error (TqE) and rotation deviation (RotD) were measured with a torque geometric triangle and a toolmaker's microscope, respectively. Both torque and rotational measurements were evaluated statistically as algebraic and absolute numeric values, using analysis of variance with repeated measures. RESULTS: Absolute TqE and RotD were significantly (P < .001) higher in direct than in indirect bonding techniques higher in both the labial and lingual bracket systems by twofold and threefold, respectively (LbD = 7.26 degrees , 1.06 mm; vs LbI = 3.02 degrees , 0.75 mm; LgD = 8.42 degrees , 1.13 mm; vs LgI = 3.18 degrees , 0.55 mm). No statistically significant difference was found between labial and lingual systems for the same bonding technique. Maxillary incisors demonstrated the largest RotD angle (eg, right lateral: 12.04 degrees ). A distal off-center RotD was predominant in the mandibular dentition. CONCLUSIONS: Labial and lingual systems have the same level of inaccuracy. For both systems, indirect bonding significantly reduces absolute TqE and RotD. The TqE found can cause transverse discrepancy (scissors or crossbite) combined with disclusion with antagonist teeth. The RotD found can result in irregular interproximal contact points.

Comparison of lateral photographic and radiographic sagittal analysis in relation to Angle's classification.

OBJECTIVE: The goal of this study was to compare sagittal jaw relationships derived from standardized profile photographs (soft tissue) to those derived from lateral cephalograms (hard tissue) with respect to Angle's classification of malocclusion. METHODS: A total of 110 randomly selected subjects (mean age: 13.75 ± 1.46 years) undergoing treatment (Postgraduate Program in Orthodontics at Tel Aviv University) were assigned to three groups based on Angle's classification (Class I: n = 30; Class II: n = 50; Class III: n = 30). Standardized profile-view photographs and lateral radiographs (cephalograms) were compared using 11 soft tissue and 8 skeletal measurements, respectively. RESULTS: Tragus, infra-orbital, nasion, A point, B point, and pogonion were found to be the most reliable soft tissue reference points. A similar pattern of diversity was found between the three groups of Angle's classification (Class I/II/III) for the photographic soft,-tissue and the radiographic skeletal measurements (e.g., soft tissue A'N'B' =11.43°/13.30°/8.85° and hard tissue ANB = 3.13°/4.64°/-1.31°). Soft tissue A'N'B' measurement provides complementary information to hard tissue ANB measurement. CONCLUSION: Analyzing profile photographs for evaluating sagittal jaw relationships is a practical tool in determining soft tissue harmony. Soft tissue measurements provide a sagittal differential diagnosis in relation to Angle's classification of malocclusion.

Anchorage loss--a multifactorial response.

Anchorage loss (AL) is a potential side effect of orthodontic mechanotherapy. In the present study, it is defined as the amount of mesial movement of the upper first permanent molar during premolar extraction space closure. In addition, AL is described as a multifactorial response in relation to the extraction site, appliance type, age, crowding, and overjet. For this study, 87 university clinic and private practice subjects, who were defined as maximum anchorage cases and had undergone bilateral maxillary premolar extractions, were divided into four groups according to extraction site (first vs second premolars), mechanics (lingual vs labial edgewise appliances), and age (adolescents vs adults). Overjet and crowding were examined from the overall sample. Data were collected from serial lateral cephalograms and dental casts. The results showed that as the severity of dental crowding increased, AL significantly decreased (r = -0.66, P = .001). Labial edgewise appliances demonstrated a significantly greater AL than did lingual edgewise appliances (1.15 +/- 2.06 mm, P < .05). A greater, though not statistically significant, AL was found in adults than in adolescents (0.73 +/- 1.43 mm). There was a slight nonsignificant increase in AL between maxillary second compared with first premolar extractions (0.51 +/- 1.33 mm). Overjet was weakly correlated to AL. These results suggest that AL is a multifactorial response and that the five examined factors can be divided into primary (crowding, mechanics) and secondary factors (age, extraction site, overjet), in declining order of importance.

An ortho-surgical approach to severe impaction using bone crestal bridge: a case report.

Impaction of both mandibular canine and lateral incisor is a rare clinical finding which is often treated by way of surgical extraction. This decision is often taken because of the anatomical limitations presented by the mandible, and the horizontal position of the impacted teeth, which have occasionally transmigrated, placing them in close proximity to the roots of neighboring teeth and with a high risk for causing their resorption. In addition, this condition significantly increases the likelihood that the area involved will undergo gingival recession and loss of crestal bone if an unsophisticated ortho-surgical approach is undertaken. The present report describes a novel ortho-surgical technique which maintains the alveolar crestal bone and utilizes a lingual arch attached to the first molars with traction through tunneling with super-elastic springs. This combined approach eliminated the need for extraction of the impacted teeth, and accomplished their full alignment without any of the aforementioned side effects. Every dentist (general practitioners as well as specialists) should be aware of this procedure and refer patients to a specialist.

Skeletal and dental response to rapid maxillary expansion with 2- versus 4-band appliances.

PURPOSE: Banding a rapid palatal expansion (RPE) appliance to the 2 first molars has been proposed as an equivalent to the conventional 4-band RPE appliance. However, the dentoskeletal response to this treatment has not been evaluated. MATERIAL: Twenty-eight subjects (aged 8-20 years) who required maxillary expansion were matched by age and randomly assigned to either a 2-band or a 4-band RPE group. Skeletal and dental responses were measured from standardized anteroposterior cephalometric and occlusal radiographs and dental casts before treatment (T1), at the end of expansion (T2), and at 1 year postexpansion (T3). RESULTS: At T2, suture expansion was 2.5 times greater and arch perimeter was 6-fold larger in the 4-band than in the 2-band group. Both appliances displayed the typical "V" expansion of the suture and "reverse V" expansion of the dental arch. At T3, remineralization reduced the suture opening by 75%, but 95% to 99% of the dental reaction was maintained. The 2-band group demonstrated a significant inverse age-dependent correlation ( r = -0.795), with treatment failure beyond 12 years of age, whereas the 4-band group was age-independent. CONCLUSIONS: The greater the skeletal resistance, the smaller the sutural response but the greater the dental response to RPE therapy. Four-band RPE is indicated when severe anterior crowding is accompanied by a tapered arch form, and 2-band RPE is recommended in the mixed dentition when mild crowding occurs with posterior constriction.