Mm Of Crowding Research Articles

The incidence and severity of open gingival embrasures in adults treated with clear aligners and fixed appliances: a retrospective cohort study

BackgroundTo evaluate the incidence and severity of open gingival embrasures (OGEs) in adult patients treated with clear aligners and fixed appliances.MethodsTwo hundred non-extraction adult subjects with less than 5 mm of crowding (mean age, 24.6 ± 3.8 years) were enrolled in this retrospective study. The subjects were divided into the clear aligner (n = 100) and fixed appliance group (n = 100). The intraoral photographs were utilized to determine the incidence of OGEs in the upper arch between maxillary central incisors, as well as the lower arch between mandibular central incisors. Crown overlap, crown shape, posttreatment root angulation, the distance from the interproximal contact point (ICP) to the alveolar bone crest (ABC) after treatment and interproximal enamel reduction (IPR) were determined in the two groups.ResultsThe incidence of OGEs between maxillary and mandibular central incisors after orthodontic treatment was 35.0% and 38.0% in the clear aligner group, respectively, significantly higher than that (18.0% and 24.0%) in the fixed appliance group (P < 0.05). The average area of an OGE after clear aligner treatment was larger both in the maxilla (0.16 ± 0.12mm2) and mandible (0.21 ± 0.24mm2) compared with that (0.05 ± 0.03mm2 and 0.05 ± 0.06mm2) after fixed appliance treatment (P < 0.05). No difference was found regarding pretreatment crown overlap, crown shape, treatment duration, posttreatment root angulation, amount and distribution of IPR and the distance from ICP to ABC.ConclusionsThe incidence and severity of OGEs were higher in adults treated with clear aligners. Clinicians should be aware of the risk of OGEs during treatment with clear aligners.

A comparison of SureSmileTM, InsigniaTM, and InvisalignTM, in treating non-extraction cases of mild to moderate crowding: a prospective clinical trial

Abstract Objectives: To compare the ability of SureSmileTM, InsigniaTM and InvisalignTM to achieve predicted intra-arch tooth positions and further compare their objective grading scores for alignment/rotations, marginal ridge relationships and buccolingual inclination. Materials and methods: The study was a prospective clinical trial of 145 arches from 44 females and 29 males (54 SureSmileTM arches, 35 InsigniaTM arches, and 56 InvisalignTM arches). All arches were treated by a non-extraction approach and had ≤7 mm of crowding and 45° of tooth rotation. The manufacturer’s recommendations were followed for each group and the final scans were acquired before refinements, rebonding, or wire bending. The virtual set-ups were superimposed on the final scans and the coordinates of 34 landmarks per arch were compared. One hundred and twenty-six end-of-participation arches were suitable for 3D printing and were compared using the American Board of Orthodontics Objective Grading Scores (OGS) for alignment/ rotations, marginal ridge relationships, and buccolingual inclination. Results: No statistically significant differences were identified in the mean deviation between the target and achieved the position of the anterior landmarks within the treatment groups. The exception was the Suresmile group which had greater vertical discrepancies in the position of the labial CEJ. Although the mean differences between the target and achieved anterior landmark positions for all groups were under 0.5 mm, the range of maximum discrepancy was between 0.7 mm and 4.1 mm. The InsigniaTM system showed significantly greater deviation in upper posterior landmark positions in the transverse and sagittal dimensions, and lower posterior landmarks in the transverse dimension. However, this was due to the InsigniaTM initial set-ups being wider. There was no statistically significant difference between the three systems in combined intra-arch OGS. However, the InvisalignTM system had a significantly poorer alignment/rotation score than the SureSmileTM group. The InsigniaTM system performed better in achieving buccolingual tooth inclination compared to SuresmileTM, and the InvisalignTM system performed better than the SuresmileTM system in the marginal ridge score. Conclusions: The three systems were comparable in achieving the predicted tooth positions of the anterior teeth in non-extraction, mild-to-moderate, crowded cases. Large discrepancies requiring operator intervention were common within the three systems. Although the three systems had no statistically significant difference in overall intra-arch OGS scores, there were significant differences in the score components.

Treatment Time of Class II Malocclusion, with and without Mandibular Crowding, Treated with Four Premolar Extractions: A Retrospective Study.

This study aimed to compare the treatment times in patients with complete bilateral Class II malocclusion, with and without mandibular crowding, treated with 4 premolar extractions. The sample comprised 57 retrospectively and consecutively selected patients (30 male, 27 female) treated for initial Class II malocclusion, divided as follows: Group 1 consisted of 23 patients (11 males, 12 females; mean age 13.13 years) presenting no crowding or 3 mm at most. Group 2 consisted of 34 patients (19 males, 15 females; mean age13.06 years) presenting more than 4 mm of crowding. Crowding was manually measured in the initial dental casts. The Objective Grading System (OGS) index was manually measured in the final dental casts and radiographic images. The groups were comparable regarding initial age, gender distribution, and final occlusal statuses. The treatment times between the groups were compared using the t-test. Correlation between crowding and treatment time was evaluated with Pearson correlation coefficient. Treatment times between the 2 groups were similar (P = .890) and there was no significant correlation between the amount of crowding and treatment time (r = 0.04, P = .760). Treatment times for complete Class II malocclusion with and without mandibular crowding, treated with 4 premolar extractions, are similar.

Linear regression.

Linear regression.

Changes in mandibular incisor position and arch form resulting from Invisalign correction of the crowded dentition treated nonextraction.

To investigate changes in mandibular incisor position resulting from Invisalign correction of the crowded dentition without extraction. A retrospective chart review was completed on 61 adult White patients. Patients were categorized into three groups based on the value of pretreatment crowding of the lower dentition: 20 mild (2.0-3.9 mm), 22 moderate (4.0-5.9 mm), and 19 severe (>6.0 mm). Cephalometric radiographs were measured to determine lower incisor changes. Interproximal reduction and changes in arch width were also measured. Statistical evaluation of T0 and T1 values using paired t-tests and analysis of covariance were applied to evaluate mean value changes. Lower incisor position and angulation changes were statistically significant in the severe crowding group. There were no statistically significant differences in lower incisor position between the mild and moderate crowding groups. There was a statistically significant increase in buccal expansion in each of the three groups. Invisalign(®) treatment can successfully resolve mandibular arch crowding using a combination of buccal arch expansion, interproximal reduction, and lower incisor proclination. When there is <6 mm of crowding, lower incisor position remained relatively stable. The lower incisors proclined and protruded in the more severely crowded dentitions (>6 mm).

Perceptions of dental professionals and laypeople to altered maxillary incisor crowding

The aim of this study was to determine how sensitive dental specialists and laypeople are to maxillary incisor crowding when viewed from the front. Computer technology was used to create a series of photographs of the incisors of a smiling woman viewed from the front. The photographs showed varying degrees of maxillary incisor crowding classified according to Little's irregularity index (LII). The incisors illustrated in the photos were ranked on a scale from perfect alignment to severely crowded. The rating was done by 4 groups of people: orthodontists, general dentists, laypeople with experience of orthodontic treatment, and laypeople with no history of orthodontic treatment. The orthodontists and the general dentists noted misalignment of 1 central incisor when the LII reached 1.5mm, whereas the laypeople with or without experience of orthodontic treatment were sensitive to 2.0mm of crowding. When the LII reached 2.0mm for 1 lateral incisor, it triggered the orthodontists to consider providing orthodontic treatment, whereas this degree of irregularity was ignored by the general dentists and laypeople. When both central incisors were misaligned, the orthodontists were sensitive to the fact at 2.0mm of LII, whereas the general dentists and the laypeople with experience of orthodontic treatment became sensitive at 3.0mm of LII, and the laypeople with no history of orthodontic treatment were sensitive at 4.0mm of LII. When both lateral incisors were misaligned, the orthodontists noted the crowding at an LII of 3.0mm, the general dentists became sensitive at an LII of 4.0mm, whereas both the laypeople with experience of orthodontic treatment and the laypeople with no history of orthodontic treatment ignored it. When the crowding of all maxillary incisors reached an LII of 4mm, both the orthodontists and the general dentists were alerted to the fact, but both the laypeople with experience of orthodontic treatment and the laypeople with no history of orthodontic treatment were sensitive only to a total incisor crowding equal to an LII of 6.0mm. Orthodontists are more critical than other groups when evaluating the misalignment of the maxillary incisors. It appears that the central incisors play a more important role than do the lateral incisors when dental crowding impacts smile esthetics. For all observer groups, it also appears that people are more sensitive to the misalignment of a single tooth than they are to the same level of crowding distributed over multiple teeth.

How good are we at estimating crowding and how does it affect our treatment decisions?

To assess the estimation of crowding by orthodontists and their subsequent extraction choices. Sixty-two orthodontists were asked to quantify crowding on eight lower arch study models using their preferred method and also to indicate possible extraction choices. For each model, the intermolar widths, intercanine widths, and clinical scenarios were identical, but the true crowding varied from 0.1 to 7.5mm across the eight models as to a lesser extent did the curve of Spee. Eleven orthodontists repeated the exercise after 9 months to assess reliability. The preferred method of space estimation by all of the orthodontists was direct visualization. However, the estimates of crowding were very variable. For the most crowded lower model with 7.5mm of crowding, the estimates ranged from 5 to 20mm. Extraction choices were less variable than estimates of crowding and shifted from second to first premolars as crowding increased. Estimates of crowding and treatment decisions changed with time in 28 of 33 repeat measures. Estimates of crowding were unrelated to clinical experience. The principal limitation of this study is that it was a laboratory-based study and utilized just the lower arch model for estimation and treatment planning. Extraction decisions and estimates of crowding tended to vary both initially and over time but were less varied in the case of the extraction decisions. Although this may have been a reflection of the limited treatment options, perhaps reassuringly, as the degree of crowding increased, so did the likelihood of prescribing extractions and the decisions generally shifted from second to first premolars. How orthodontists estimate crowding and make subsequent extraction choices is important and has potential medico-legal implications.

Mastering interproximal stripping: with innovations in slenderization.

ABSTRACTCrowding and irregularity remain a consistent problem for children. Management of space problems continues to play an important role in a dental practice. It also represents an area of major interaction between the primary provider and the specialists. Proximal stripping is routinely carried out to avoid extraction in borderline cases where space discrepancy is less and in cases where there is a discrepancy between the mesio- distal width of maxillary and mandibular teeth to satisfy Bolton ratio. Proximal stripping is carried out using of metallic abrasive strip, safe sided carborundum disk, or with long thin tapered fissure burs with air rotor.The use of rotary cutting instrument can harm the pulp by exposure of mechanical vibration and heat generation (in some cases). Whereas, the large diameter of the disk obstructs vision of the working area. Also fracturing away a portion is a common problem with disk. Tapered fissure burs cut the tooth structure as the width of bur or overcutting may occur of the tooth structure due to high speed. The use of metallic abrasive strip is the safest procedure amongst the above. The strip can be placed in the anterior region without any difficulty but using it in the posterior region is difficult as, it is difficult to hold it with fingers while stripping the posterior teeth.To avoid this inconvenience here with a simple and economical way of fabricating strip holder from routine lab material is presented.Clinical implications: Proper management of space in the primary and mixed dentitions can prevent unnecessary loss in arch length. Diagnosing and treating space problems requires an understanding of the etiology of crowding and the development of the dentition to render treatment for the mild, moderate and severe crowding cases. Most crowding problems with less than 4.5 mm can be resolved through preservation of the leeway space, regaining space or limited expansion in the late mixed dentition. In cases with 5 to 9 mm of crowding, some can be approached with expansion after thorough diagnosis and treatment planning. Most of these cases will require extraction of permanent teeth to preserve facial esthetics and the integrity of the supporting soft tissue. Sequential proximal stripping is routinely carried out to avoid extraction in borderline cases where space discrepancy is less and reserved for treatment of mild tooth-size/arch-size discrepancies.How to cite this article: Sharma NS, Shrivastav SS, Hazarey PV. Mastering Interproximal Stripping: With Innovations in Slenderization. Int J Clin Pediatr Dent 2012;5(2):163-166.

Treatment of crowding in the mixed dentition

Am J Orthod Dentofacial Orthop 2002;121:569-71

MANAGEMENT OF SPACE PROBLEMS IN THE PRIMARY AND MIXED DENTITIONS

According to the Third National Health and Nutrition Examination Survey, crowding and irregularity remain a consistent problem for children. Management of space problems continues to play an important role in a dental practice. It also represents an area of major interaction between the primary provider and the specialists. This article attempts to update clinicians on the current knowledge of space management. Proper management of space in the primary and mixed dentitions can prevent unnecessary loss in arch length. Diagnosing and treating space problems requires an understanding of the etiology of crowding and the development of the dentition to render treatment for the mild, moderate and severe crowding cases. Most crowding problems with less than 4.5 millimeters can be resolved through preservation of the leeway space, regaining space or limited expansion in the late mixed dentition. In cases with 5 to 9 mm of crowding, some can be approached with expansion after thorough diagnosis and treatment planning. Most of these cases will require extraction of permanent teeth to preserve facial esthetics and the integrity of the supporting soft tissue. Serial extraction or guidance of eruption is reserved for treatment of severe tooth-size/arch-size discrepancies. Due to variations in the timing and extraction sequence depending on the diagnosis, serial extraction should be reserved for those who can complete the treatment successfully. The recommended timing of referring patients with moderate crowding to specialists for treatment is in the late mixed-dentition stage of development. Patients with severe crowding will require earlier evaluation for serial extraction.

Reliability of the Bolton tooth-size analysis when applied to crowded dentitions.

The Bolton tooth-size analysis is widely taught and used in orthodontics. However, its reliability has not been documented. The purpose of this study was to evaluate the reliability of the analysis when performed with needle-pointed dividers and a Boley gauge. Four clinicians measured the teeth on 15 sets of casts with two instruments at two sessions. The measurements were used to calculate tooth-size excess. To evaluate the measurement error, the difference between the two analyses made by the same investigator on the same set of casts was calculated. More of the same-investigator analyses were significantly correlated when the Boley gauge was used than when the needle-pointed dividers were used. Between-investigator analyses revealed significant correlations for each measurement session with both instruments. Every investigator was found to have at least one measurement error for each analysis and with each instrument that was as large as a clinically significant result of a Bolton analysis. The results of this study demonstrate that clinically significant measurement errors can occur when the Bolton tooth-size analysis is performed on casts with at least 3 mm of crowding. The Boley gauge demonstrated a higher frequency of significantly correlated repeated measures and thus may be somewhat more reliable for this analysis than the needle-pointed dividers.