Volume 35 (2019): Issue 1 (January 2019)

It is reported that in New Zealand financially disadvantaged adolescents are less likely to access orthodontic treatment than the more affluent in society.

The aim of the study was to investigate the attitudes of a group of New Zealand orthodontists towards the current fee-for-service model of treatment funding. A second aim was to explore orthodontists’ perceptions of how the affordability of orthodontic treatment affects low socio-economic families.

As part of the project, 11 volunteer orthodontists were interviewed. A subsequent content analysis of the collected data was performed.

Most participants reported that parents would feel inadequate if they were unable to secure orthodontic treatment for their child; however, some participants also indicated that it was common for parents to ‘go without’ to fund their child’s treatment. Most participants maintained that the government should only fund treatment for severely disabling malocclusions but not other treatments due to the limited health budget and orthodontic treatment being primarily considered for aesthetic reasons. Some participants reported that if the government funded orthodontic treatment, it would result in over subscription and compromised standards of care.

Despite some low socio-economic families being unable to access orthodontic treatment because of the expense, the current fee-for-service model may be the best method for delivering high standards of orthodontic care.

To evaluate the level of force required to axially dislodge nickel titanium compression hooks (Trillium Compression Hook^TM, Hespeler Orthodontics) placed on orthodontic arch wires in vitro.

Nickel titanium compression hooks were placed on arch wires with a specially designed pair of pliers. The resistance to axial dislodgement was tested on a total of 260 hooks placed in a standardised way on round (0.016″, 0.018″, 0.020″), square (0.020 × 0.020″) and rectangular (0.016 × 0.022″, 0.019 × 0.025″, 0.021 × 0.025″) stainless steel (Rocky Mountain Orthodontics), nickel titanium, or β-titanium (Hespeler Orthodontics) arch wires. The forces required to displace the hooks were recorded using an Instron tensile testing machine. The data were compared with the results reported in similar studies on stainless steel crimpable arch wire hooks.

The forces required to dislodge the compression hooks varied between 45.0 N and 161.9 N. The hook’s resistance to dislodgement was found to be high in all tested hook/wire combinations. The lowest recorded average dislodging force was found in the 0.020″ nickel titanium group and the highest average force was in the 0.016 × 0.022″ β-titanium group.

The forces needed to dislodge the tested nickel titanium compression arch wire hooks exceed the force levels previously reported for stainless steel crimpable arch wire hooks.

Numerous studies have indicated that a malocclusion possibly affects young people’s well-being and oral health-related quality of life (OHRQoL). Dento-facial aesthetics may influence how people are judged and may elicit social consequences such as bullying and negative comments. The present study aimed to explore the impact of a malocclusion on young New Zealanders who sought subsidised treatment from the Wish for a Smile (WFAS) organisation and to determine their motivation for seeking care.

A qualitative thematic analysis of 151 application letters to WFAS from young people (aged 11–18 years) and their caregivers was supplemented by telephone interviews of nine successful and nine unsuccessful applicants to explore their experiences through their own words.

In both the letters and the interviews, young people most commonly reported psychological impacts, followed by social and emotional effects associated with their malocclusion. Physical impacts were less commonly reported. In their application letters, caregivers, although at lower frequencies, reported that the young people experienced the same impacts. One caregiver referred to the young person’s malocclusion as a temporary disability.

For some young people, a malocclusion may lead to social consequences that are disabling. When considering funding options, it is important to note the individual experience and the impact that a malocclusion might have upon the young person’s well-being.

To investigate the prevalence of cervical vertebral anomalies (CVA) in a group of patients presenting with cleft lip and palate (CLP) and to compare with a non-cleft population.

The sample comprised of 150 lateral cephalograms of non-syndromic patients with CLP and 150 non-cleft age-matched controls. The age range of both groups covered 6 to 20 years. An expert radiologist blinded to the cleft status evaluated the cephalograms for CVA and categorised them into normal, fusion, dehiscence and multiple cervical anomalies. The cleft group was subdivided according to the types of cleft (UCLP/ BCLP/ CPO) and gender (male/female). The CVA prevalence was compared between the cleft and non-cleft patients.

The prevalence of CVA was 37.7% and 20.7% in cleft and non-cleft patients, respectively. The difference was statistically significant with a p-value <0.01. Of the types of clefts, a left UCLP had the highest prevalence of CVA (47.2%), with fusion (35.8%) most commonly seen. On comparing CLP with CPO, no significant variation was observed between the types of anomalies.

A high prevalence of CVA was observed in cleft patients compared with non-cleft subjects. The prevalence of CVA was similar between males and females. The practitioner should carefully evaluate the lateral cephalogram of CLP patients for CVA, which otherwise may remain undetected and lead to neurological symptoms later in life.

To characterise the mechanical properties and galvanic coupling of Ni-free orthodontic brackets with stainless steel (SS) and Nickel-Titanium (NiTi) orthodontic wires.

Three Ni-free bracket types (Topic [TOP], Equilibrium [EQU] and Orthos [ORT] made of Ni-free alloys), one conventional (Mini 2000 [MIN]) made of SS alloy and an SS and a NiTi wire were examined in the present study. All brackets and wires were embedded in epoxy resin and, after metallographic grinding and polishing, the Martens hardness (HM), the indentation modulus (E_IT), and the elastic index (η_IT) were recorded, employing Instrumented Indentation Testing (IIT) by monitoring force over indentation depth curves during a loading-unloading cycle. The galvanic coupling of all bracket-wire combinations was tested in 0.1M NaCl-0.1M lactic acid and 0.3% (wt.) NaF solutions by noting the potential differences over 48 hours. The mechanical properties were statistically analysed by one-way ANOVA and Tukey multiple comparison tests at alpha = 0.05.

Significant differences were identified in the mechanical properties of the materials tested. The TOP (2372 ± 182 N/ mm²), ORT (wing) (2418 ± 164) and SS wire (2302 ± 85) showed significantly higher HM compared with all other materials tested. The MIN (base) (1115 ± 81) and ORT (base) (1237 ± 101) showed the lowest HM while MIN (wing) (1520 ± 138), EQU (1620 ± 139) and NiTi wire (1526 ± 42) demonstrated intermediate HM values. The ORT (wing) (101 ± 6 GPa) displayed the highest E_IT while NiTi wire (24 ± 5) showed the lowest. The latter had the highest elastic index (59 ± 5%) with MIN (base)(15 ± 3) possessing the lowest. The potential difference for all bracket wire combinations was found below the threshold for the initiation of galvanic corrosion (200 mV) apart from MIN coupled with NiTi wire in the NaF solution.

The mechanical properties of Ni-free brackets are significantly different compared with the SS bracket assessed. Galvanic testing revealed that conventional and Ni-free brackets are compatible with both SS and NiTi wires in media containing chloride and fluoride ions.

Adult patients presenting with skeletal discrepancies may refuse surgical intervention.

Thirty-two patients who declined orthognathic correction of their maxillo-mandibular dysplasia and who were without signs of temporomandibular dysfunction (TMD) were offered mandibular repositioning as a non-invasive alternative. Simulating a skeletal correction, it was explained that the approach was based on results described in case reports.

Before commencing treatment, initial records, lateral and frontal head films, study casts and photos were obtained (T0) and the mandible was repositioned to camouflage a retrognathic skeletal discrepancy or a mandibular transverse asymmetry by means of an occlusal build-up using Triad™ gel.

Three months later (T1), 23 patients had adapted to the new occlusion reflected by an absence of functional disturbance and without fracture of the composite occlusal build-up. Mandibular position in these patients was maintained by additional orthodontic treatment and an adjustment of the occlusion to the built-up postured position (T1). The skeletal changes occurring during repositioning were assessed on sagittal and frontal head films while intra-articular changes occurring during a two-year follow-up period (T2) were evaluated on images constructed from CBCT scans. No significant change, either in the direction of relapse or in the direction of further normalisation of condylar position, were observed during the two-year observation period.

Mandibular repositioning is a non-invasive intervention that may be considered a valid alternative to surgery in selected patients. Morphological variables from the radiographs taken at T0 and the results of the initial clinical evaluation of dysfunction yielded only vague and insignificant indicators regarding the predictability of the adaptation. A CBCT scan at T0 might have contributed to the identification of the patients who would likely accept the repositioning.

Orthodontic miniscrews are used to obtain skeletal anchorage during orthodontic treatment and their application is growing due to the simple method of placement and removal, which invites improved patient compliance without significant impact on function and aesthetics. However, complications and risks are reported that underscore the need for a thorough preoperative assessment to enable accurate placement, especially in confined sites. A novel approach is presented which employs a custom-designed 3D-printed splint to facilitate a fully-guided placement of orthodontic miniscrews.

The presented splint was virtually planned using coDiagnostiX® software after matching the DICOM data and STL file, to enable fully-guided screw insertion. Insertion depth was defined by a sleeve tube height that provided a depth stop when contact was reached with the head of the hand piece. Additionally, to prevent movement of the insertion instrument, a custom metallic sleeve was designed and 3D-printed by a metallic printer.

Accurate placement was achieved and no complications were experienced during insertion and use.

The insertion approach provides more predictable results and enables accurate placement of orthodontic screws. The procedure avoids associated risks and complications primarily encountered in difficult cases.

Micro-osteoperforation (MOP) is a newly developed technique reported to accelerate orthodontic tooth movement.

The following case report discusses a peripheral ossifying fibroma (POF), as a reactive gingival nodule that developed eight weeks after a patient underwent transmucosal MOP at multiple sites in the mandible during orthodontic treatment.

The MOP procedure is a relatively new approach applied to orthodontics that may induce gingival reactive nodules. Clinicians should be aware of this possible sequela and inform patients of the potential risk.