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- Première publication
- 01 May 1967
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The incidence and severity of root resorption following orthodontic treatment using clear aligners
Pages: 130 - 137
The aim of this study was to assess the incidence and severity of root resorption in patients who were orthodontically treated by clear aligner therapy.
Linear tooth lengths of maxillary and mandibular teeth from the second molar to second molar were measured from pre- and post-treatment cone beam computed tomography examinations of 25 patients who were treated by a clear aligner system.
Mean reductions in tooth length varied according to tooth type, with maxillary central and lateral incisors experiencing the most resorption, of 0.5 ± 0.41 mm and 0.4 ± 0.56 mm respectively. All tooth types had most resorption fall within the <0.25 mm range, with 7% of central and lateral incisors accounting for resorption >1.5 mm. Although the level of resorption identified in this study was less than that reported for fixed appliances, overall, the trends were similar.
Orthodontic treatment carried out with clear aligners resulted in root resorption that was largely clinically insignificant. There was a general trend towards more resorption affecting anterior teeth in both the maxilla and mandible. Original tooth length was found to be a predictor of the amount of resorption.
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2020 survey of Australian orthodontists’ procedures
Pages: 138 - 145
This second survey of Australian Society of Orthodontists members was conducted to assess their treatment preferences and compare with the results of the 2013 survey.
Invitations to participate in an online survey were sent to a total of 481 members of the Australian Society of Orthodontists (ASO) and 142 replies were received (29.5% response).
There is an average of one ASO member orthodontist per approximately 48,653 people in Australia. The average age of orthodontists is decreasing (median age = 49) but there is an increasing proportion of female orthodontists (25% up from 16%). Although practitioners preferred to wait and treat later for Class II cases, the Twin Block remained the most popular appliance for early intervention. TAD supported distalisers showed the biggest increase in popularity of Class II correction appliances although TAD use in general had declined slightly. The median extraction rate decreased from 23% in 2013 to 20% in this survey. Clear aligners were being used in a median 10% of cases (range 0% – 97%) with 18% of respondents producing in-house fabricated aligners. The most common clinical research question ASO members would like examined related to clear aligners.
Orthodontics in Australia has evolved since 2013 with an increase in the use of clear aligners and associated technology.
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Assessment of microdamage caused by orthodontic miniscrew pilot holes
Pages: 146 - 152
The clinical success of orthodontic miniscrew implants may be improved after pre-drilling a pilot hole. However, the amount of microdamage to the bone surface produced by the pilot hole is largely unknown. The present study aimed to quantify the damage to cortical bone after the creation of a pilot hole.
Porcine tibia bone was prepared into 30 rectangular bone block specimens with widths of 1.5, 2.0 or 2.5 mm. A pilot hole (0.9 mm diameter) was drilled into each bone specimen. Sequential staining allowed the microdamage on the entry and exit surfaces to be imaged by a confocal laser scanning microscope. Image analysis software was used to measure histomorphometric parameters.
The specimens had a mean total damage area of 0.95 mm2, a maximum damage radius of 0.66 mm and a maximum crack length of 0.18 mm. There were no significant differences between the three bone thicknesses for any of the histomorphometric parameters on the entry and exit surfaces (
Microdamage caused by the creation of a pilot hole in the cortical bone was minimal and did not appear to be influenced by bone thickness. Therefore, pilot hole pre-drill protocols may be implemented without introducing significant cortical bone microdamage.
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Social media and orthodontics: An analysis of orthodontic-related posts on Instagram
Pages: 153 - 159
The objective of this study was to determine the quality and content of orthodontic-related posts on Instagram.
Eight orthodontic-related ‘hashtags’ were determined, and a total of 240 posts divided into 30 posts from each hashtag were investigated at two different time periods. Duplicate and unrelated posts were excluded from the study.
A total of 227 Instagram posts (182 photographs, 45 videos) were analysed at two evaluation periods. The number of deleted Instagram posts was 13 and all were photographs. Most educational content was liked in the #orthodontics hashtag of the eight determined hashtags (
It was noted that Instagram is mainly used by dental professionals rather than for advertising purposes. Orthodontists should be aware of the content of social media platforms and educate and direct their patients towards correct and reliable Instagram resources.
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Impacted maxillary canines and their relationship with lateral incisor resorption: a cone beam computed tomography (CBCT) study
Pages: 160 - 167
The spatial position of a canine can affect the level of proximal root resorption and the success of orthodontic treatment. The aim of this study was to examine the mesiodistal and vertical position of impacted maxillary canines and to assess their relationship with the lateral incisor by using cone beam computed tomography (CBCT).
One hundred and sixty-nine CBCT scans of patients presenting with maxillary impacted canines were included in the study. The buccopalatal, mesiodistal (classified as sectors I, II, III, IV from distal to mesial) and vertical (cervical, middle, apical) position of the maxillary impacted canines were determined. The positional effect on the morphology (width, length, and depth) and resorption was assessed on the roots of the maxillary lateral incisors. Obtained data were statistically analysed by using Student
Of the maxillary impacted canines, the 34.72% that had associated resorption on the adjacent lateral incisors were buccally positioned, and 65.28% were palatally positioned. While 45.58% of sector I impacted maxillary canines were buccally positioned, 68.31% of sector IV impacted maxillary canines were palatally positioned. Furthermore, there was a statistical significance between the mesiodistal position and palatal or buccal maxillary canine impaction (
While all maxillary impacted canines had the potential to cause lateral incisor resorption, there was no close relationship related to the canine’s buccopalatal, mesiodistal and vertical position. Nevertheless, if an impacted maxillary canine migrated towards the midline, the buccopalatal and vertical position of the tooth changed from buccal to palatal and cervical to apical, respectively.
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Facebook legal and regulatory advertising compliance by specialist orthodontic practices: a cross-sectional survey
Pages: 168 - 174
Healthcare providers are increasingly using social media websites such as Facebook to advertise their services. The Australian Health Practitioner Regulation Agency guidance on the advertising of healthcare is based on the National Law in Australia and prohibits advertising that is contrary to the patient’s best interests.
To determine the legal and regulatory advertising compliance of the Facebook pages of specialist orthodontic practices in Australia.
The Facebook pages of specialist orthodontic practices were identified following a systematic search strategy. The content uploaded to each ‘eligible’ page between March 2019 and February 2020 was reviewed with regard to five specific domains of prohibited advertising. Cronbach’s Alpha Test was used to determine intra-rater agreement.
The Facebook pages of 147 specialist orthodontist practices in Australia, representing 288 specialist orthodontists, satisfied inclusion criteria. Most Facebook pages (82.3%) breached the Law in one or more domains. The mean number (standard deviation) of domains breached was 1.65 (1.3), range 0–5. Non-compliance regarding ‘the use of testimonials’ (76.9%) and ‘information that was likely to create unrealistic expectations of orthodontic treatment’ (40.8%) were the domains most commonly contravened. All five domains were breached in 5.4% of practice Facebook pages. Intra-rater scores were strong, ranging from 0.84 to 0.94.
Compliance of the Facebook pages of specialist orthodontic practices in Australia with legal and regulatory advertisement requirements is poor. Greater awareness of the relevant obligations by specialist orthodontists responsible for their practice Facebook content is necessary to ensure that their advertising is not liable to charges of legal and/or professional misconduct.
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Local orthodontic force initiates widespread remodelling of the maxillary alveolar bone
Pages: 107 - 115
To clarify the effects of a local orthodontic force on alveolar bone by analysing bone remodelling in different regions of the maxilla during orthodontic tooth movement (OTM).
An OTM model was established in rats. Histological changes in the maxilla were analysed using TRAP staining, IHC staining for CTSK and haematoxylin and eosin (H and E) staining. The root bifurcation region of the alveolar bone of the first (M1), second (M2) and third (M3) molars were selected as the regions of interest (ROIs), which were further divided into a cervical and an apical level. Sequential fluorochrome labelling was performed to analyse bone deposition rates.
The maxillary left first molars were moved mesially. TRAP staining and IHC staining for CTSK showed orthodontic force increased osteoclast numbers in all six ROIs at both the cervical and apical levels. H and E staining indicated elevated osteoblast numbers in the OTM group in all induced regions. Sequential fluorochrome labelling exhibited increased bone deposition rates around M1, M2 and M3 in the OTM group.
An orthodontic force applied to the first molar could initiate widespread remodelling of the maxillary alveolar bone, which was not restricted to the tension and pressure sites. This may revise the orthodontic biomechanical theory and provide new insights for clinical work.
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A stepwise approach to the correction of excessive gingival display: an integrative review of the literature
Pages: 184 - 194
Excessive gingival display is an aesthetic concern for patients and a challenge for clinicians. An accurate diagnosis is essential in order to provide effective treatment.
The aim of the present article is to fill a gap in the current literature by providing clinicians with an overview and a stepwise approach to assessing gingival excess, as well as reviewing possible treatment.
Published articles related to smile aesthetics and excessive gingival display over the last 40 years were identified and analysed through an electronic search.
An examination should be initiated extra-orally to distinguish contributing skeletal factors. The relationships of four aesthetic parameters (LIPG): lip length (L), incisal lines (I), tooth proportions (P), and gingival lines (G), should be examined individually to determine other possible causes of gingival excess. Contributing factors may include a short or hypermobile upper lip, dentoalveolar extrusion, or altered passive eruption. Further investigation to identify patients who might benefit from orthognathic surgery, orthodontic treatment alone, lip repositioning or botulinum injection, or aesthetic crown lengthening procedures, should be conducted to reconfirm a diagnosis and provide the optimal treatment.
Clinicians can have a dental blueprint for anterior tooth reconstruction and are able to provide comprehensive treatment in co-operation with other disciplines. By understanding the principles of an aesthetic smile line, the aetiology of an excessive gingival display and treatment concepts, clinicians may provide alternative treatments to avoid extensive surgical procedures while achieving acceptable outcomes.
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A case of idiopathic condylar resorption
Pages: 195 - 204
Idiopathic condylar resorption (ICR) is a well-documented but poorly understood condition, characterised by the progressive degeneration of the temporomandibular joint without an identifiable cause. ICR most commonly presents as a spontaneous, self-limiting episode of bilateral condylar resorption in the absence of pathology, injury or systemic disease. The condition most commonly affects physically active adolescent females, and has a strong predilection for individuals with a Class II skeletal relationship. Some ICR patients exhibit symptoms such as discomfort and/or functional limitations during the active phase of resorption, though some may be completely asymptomatic.
This case report describes the ICR management of a 20-year-old female with asymptomatic bilateral condylar resorption, resulting in a rapid development of mandibular retrognathia. The retrognathic appearance was of concern to the patient and treatment was desired for this reason.
Combined orthodontic-orthognathic treatment was undertaken. Pre-surgical orthodontics was completed following ICR stabilisation, and surgical correction consisted of a mandibular advancement plus a genioplasty. The resorbed condyles were accepted given the temporomandibular joints remained asymptomatic and there were no functional limitations. Following treatment, the patient remained asymptomatic, functioning without restrictions, and satisfied with the aesthetic outcome.
The combined orthodontic-orthognathic approach addressed the aesthetic and functional concerns of the patient. The condyles were not reconstructed with prostheses and were left in their resorbed anatomical form and relationship. This illustrates the adaptive capabilities of the mandible and associated musculature, and that more complex condylar restorative procedures are not always required.
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Maxillary distraction osteogenesis and a Le Fort I osteotomy for severe maxillary retrognathia in cleft lip and palate: a case report
Pages: 205 - 210
The correction of severe maxillary retrognathia in patients presenting with a cleft palate is challenging due to the complexity of the orthodontic preparation and the magnitude of the surgical movements required, along with the relatively high risk of relapse.
An 18-year-old Caucasian male with a repaired left-side unilateral cleft lip and palate presented with concerns relating to poor facial aesthetics and poor occlusion. Multidisciplinary treatment involving orthodontics and orthognathic surgery were undertaken to correct the severe maxillary retrognathia. The correction involved the use of internal distraction osteogenesis followed by a conventional maxillary Le Fort I advancement with rotation.
Pre- and post-treatment lateral cephalogram measurements showed the maxilla was advanced 18 mm, rotated clockwise producing a 9 mm increase in vertical dimension at A point and a 7 mm gain in relative arch width across the first molars. Follow-up CBCT superimpositions showed excellent skeletal stability of the achieved anterior-posterior, lateral and vertical corrections over a 2.4-year period, although there was some minor dental relapse.
This case report illustrates the successful use of orthodontics and distraction osteogenesis followed by conventional Le Fort I advancement surgery to correct a severely retrognathic maxilla in a patient with a repaired unilateral cleft lip and palate.
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Treatment of anterior open-bite using zygomatic anchorage: a 10-year follow-up case report
Pages: 211 - 219
To present the treatment and long-term post-treatment results of an adult case presenting with an Angle Class II anterior openbite malocclusion that involved the use of zygomatic anchorage for the intrusion of the maxillary posterior teeth.
A 23-year-old female patient with a bilateral Angle Class II molar and canine relationship, a 4 mm overjet and a 6 mm anterior open-bite was treated using zygomatic anchorage in order to correct the dental and skeletal relationships, and eliminate the anterior open-bite to achieve an ideal overjet, overbite and improved facial aesthetics. Orthodontic brackets were placed on the maxillary and mandibular teeth. Under local anaesthesia, a subperiosteal flap was raised, and two titanium miniplates were bilaterally placed in the zygomatic area. The molars were intruded by applying 400 grams of force to the miniplates via connection to the upper arch wire.
By intruding the molar teeth using zygomatic anchorage, the anterior open-bite was corrected to achieve an Angle Class I occlusion, an ideal overbite and a harmonious facial profile that were successfully maintained after a 10-year follow-up period.
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Interdisciplinary approach for a patient with excessive gingival display – a case report
Pages: 220 - 227
Excessive gingival display is often an aesthetic concern for patients and a challenge for clinicians. Multiple causes are possible and focused treatment options should be considered. The aim of this article is to emphasise the importance of interdisciplinary treatment for patients presenting with excessive gingival display. A 49-year-old female patient who suffered from prominent teeth and a gummy smile was diagnosed with skeletal and dental Class II relationships and a hypermobile upper lip. Aesthetically pleasing outcomes and stable occlusal function were achieved as a result of orthodontic treatment and a surgical lip repositioning procedure. The outcome was maintained after a two-year follow–up.
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Orthodontic, periodontal and prosthodontic treatment for a periodontally compromised patient with a deep overbite
Pages: 228 - 237
Periodontitis may result in displacement, overeruption and the tilting of teeth, which can lead to occlusal prematurities and accelerate the loss of periodontal structures. Orthodontic treatment is needed to correct displaced tooth positions, but inappropriate force and tooth movement can lead to further loss of supporting tissues.
To describe the treatment of a deep overbite in a 32-year-old male with a history of periodontitis, gingival recession and missing premolars.
After evaluation, fixed appliances applying light forces were chosen as the appropriate treatment approach. A segmental arch and a utility arch technique were applied. Periodontal therapy was conducted before and throughout orthodontic care.
After 28 months of treatment, a normal overbite and overjet were restored. A displaced premolar was repositioned. Space needed for the prosthetic replacement of the missing teeth was obtained and dental implants were planned after orthodontic treatment. The height of the alveolar bone increased in some areas. After 18 months of retention, the attachment level of the upper left incisor increased approximately 1 mm.
For patients with a compromised periodontium, adequate management of the tissues is the basis of orthodontic care. Appropriate orthodontic treatment may be beneficial to periodontal health in the long term.