Effect of Orthognathic Surgery On Pulp Blood Flow and Pulp Sensibility: A Prospective Control Trial

INTRODUCTION

Orthognathic surgery has the potential to compromise the vitality of the teeth. This paper aims to assess changes in pulp blood flow (PBF) and pulp sensibility (PS) of the anterior dentition following orthognathic surgery and to assess the influence of the proximity of the surgical osteotomy on the PBF and/or PS.

METHODS

Twenty-six patients undergoing orthognathic surgery (Le Fort I or bilateral sagittal split osteotomy [BSSO]) were compared to sixteen control patients treated by fixed appliances only using Laser Doppler flowmeter (LDF) and thermal testing (CO2 snow). Surgery patients were tested at T1 (presurgery), T2 (4-5 weeks postsurgery), T3 (3 months postsurgery), and T4 (6 months postsurgery). Control patients were tested at T1 (pretreatment), T2 (6 months posttreatment), T3 (12 months posttreatment), and T4 (18 months posttreatment). Differences between the maxilla and mandible were assessed.

RESULTS

No differences in PBF or PS were recorded in the control group. In the surgery group, both jaws followed the same pattern after surgery, an initial decrease at T2 followed by a gradual recovery to pretreatment PBF levels with no significant difference between T1 versus T4 in both jaws. No difference in PBF was observed between the maxilla and mandible at any testing time interval.

CONCLUSIONS AND CLINICAL IMPLICATIONS

PBF and PS of the anterior dentition was severely affected immediately postsurgery, followed by a gradual increase to full recovery. This pattern of recovery was exhibited in both jaws. A negative sensibility response or discoloration should not be seen as an indication of irreversible ischemic pulp changes. Monitoring for at least 6 months or using LDF as a confirmatory test is required before any irreversible endodontic treatment is to be considered.

The 5C model: A proposed continuous quality improvement framework for volunteer dental services in remote Australian Aboriginal communities

OBJECTIVES

Aboriginal and Torres Strait Islander communities in remote parts of Australia are some of the most underserviced communities in regard to oral health care. These communities rely on volunteer dental programmes such as the Kimberley Dental Team to fill the gaps in care, however, there are no known continuous quality improvement (CQI) frameworks to guide such organizations to ensure that they are delivering high-quality, community-centred, culturally appropriate care. This study proposes a CQI framework model for voluntary dental programmes providing care to remote Aboriginal communities.

METHODS

Relevant CQI models wherein the (i) behaviour of interest was quality improvement, and (ii) the health context was volunteer services in Aboriginal communities were identified from the literature. The conceptual models were subsequently augmented using a 'best fit' framework and the existing evidence synthesized to develop a CQI framework that aims to guide volunteer dental services to develop local priorities and enhance current dental practice.

RESULTS

A cyclical five-phase model is proposed starting with consultation and moving through the phases of data collection, consideration, collaboration and celebration.

CONCLUSIONS

This is the first proposed CQI framework for volunteer dental services working with Aboriginal communities. The framework enables volunteers to ensure that the quality of care provided is commensurate with the community needs and informed by community consultation. It is anticipated that future mixed methods research will enable formal evaluation of the 5C model and CQI strategies focusing on oral health among Aboriginal communities.

The Kimberley Dental Team: A process evaluation of a volunteer dental programme serving remote Aboriginal communities in Australia

OBJECTIVES

This study aims to conduct a process evaluation of the Kimberley Dental Team (KDT), a not-for-profit, volunteer organization providing care to remote Aboriginal communities in Western Australia.

METHODS

A logic model was constructed to detail the operational context of the KDT model. Subsequently, the fidelity (the extent to which each of the programme's elements were implemented as planned), dose (types and quantity of services provided) and reach (demographic characteristics and communities serviced) of the KDT model were evaluated using service data, deidentified clinical records and volunteer rosters maintained by KDT from 2009 to 2019. Trends and patterns of service provision were analysed using total counts and proportions over time. A Poisson regression model was used to explore changed in the rates of surgical treatment over time. The associations between volunteer activity and service provision was also investigated using correlation coefficients and linear regression.

RESULTS

A total of 6365 patients (98% identifying as Aboriginal or Torres Strait Islander) were seen over the 10-year period with services being provided across 35 different communities in the Kimberley. Most services were provided to school-aged children, consistent with the programme's objectives. The peak preventive, restorative and surgical rates occurred among school-aged children, young adults and older adults respectively. A trend was observed indicating a reducing rate of surgical procedures from 2010 to 2019 (p < .001). The volunteer profile showed significant diversity beyond the conventional dentist-nurse structure and 40% being repeat volunteers.

CONCLUSIONS

The KDT programme maintained a strong focus on service provision to school-aged children over the last decade with the educational and preventive components being central to the care being provided. This process evaluation found that the dose and reach of the KDT model grew with an increase in resources and was adaptive to perceived community need. The model was shown to evolve through gradual structural adaptations contributing to its overall fidelity.

An evaluation of gingival phenotype and thickness as determined by indirect and direct methods

OBJECTIVES

To evaluate gingival phenotype (GP) and thickness (GT) using visual, probing, and ultrasound (US) methods and to assess the accuracy and consistency of clinicians to visually identify GP.

MATERIALS AND METHODS

The GP and GT of maxillary and mandibular anterior teeth in 29 orthodontic patients (mean age 25 ± 7.5 years) were assessed using probing and US by a single examiner. General dentist and dental specialist assessors (n = 104) were shown intraoral photographs of the patients, including six repeated images, and asked to identify the GP via a questionnaire.

RESULTS

An increasing trend in GT values of thin, medium, and thick biotype probe categories was found, though this was not statistically significant (P = .188). Comparison of probing method to determinations of GT made by US yielded slight agreement (κ = 0.12). Using the visual method, assessors' identification of the second GP determination ranged from poor to moderate agreement (κ = 0.29 to κ = 0.53).

CONCLUSIONS

The probe method is sufficient in differentiating between different categories of GP. However, further research is required to assess the sensitivity of the probe method in recognizing phenotypes in the most marginal of cases. Assessors using the visual method lack the ability to identify GP accurately and consistently among themselves.

Effect of craniofacial morphology on gingival parameters of mandibular incisors

OBJECTIVES

To investigate the association between the width of keratinized gingiva (WKG), gingival phenotype (GP), and gingival thickness (GT) with craniofacial morphology in sagittal and vertical dimensions.

MATERIALS AND METHODS

WKG, GP, and GT of mandibular anterior teeth in 177 preorthodontic patients (mean age 18.38 ± 5.16 years) were assessed clinically using a periodontal probe, a Colorvue Biotype Probe, and ultrasound by a single examiner. Patients were grouped into skeletal Class I, II, and III and hyperdivergent, normodivergent, and hypodivergent based on ANB and SN-MP angles. Mandibular incisor inclination (L1-NB) was also measured. Clinical and cephalometric measurements were repeated to assess inter- and intraexaminer reproducibility.

RESULTS

A significant association was found between thin GP and skeletal Classes I and III for the left mandibular central incisor (MCI; P = .0183). In skeletal Class III patients, L1-NB angle demonstrated a decreasing trend as phenotype thickness decreased. A significant association was found between thin phenotype and normodivergent and hypodivergent groups for MCIs (left: P = .0009, right: P = .00253). No significant association between WKG or GT and craniofacial morphology was found.

CONCLUSIONS

Thin GP is associated with skeletal Class I and III for the left MCI. Thin GP is associated with hypodivergent and normodivergent skeletal patterns for the MCIs. There was no association between WKG and GT and craniofacial morphology in both skeletal and vertical dimensions. Dental compensations that exist due to different craniofacial morphology may influence the GP.

The Kimberley Dental Team: a volunteer-based model of care serving remote Aboriginal communities

CONTEXT

Improving the oral health of Aboriginal and Torres Strait Islander people has been prioritised by both of the Australian National Oral Health Plans (2004-2013 and 2015-2024). However, providing adequate access to timely dental care to remote Aboriginal communities remains a challenge. The Kimberley region of Western Australia in particular experiences a significantly higher prevalence of dental disease compared to other regional centres. The region covers an area of over 400 000 km2, with 97% of this being classified as very remote and 42% of the population identifying as Aboriginal and/or Torres Strait Islander. The provision of dental care to remote Aboriginal communities in the Kimberley is complex and involves careful consideration of the unique environmental, cultural, organisational and clinical factors at play.

ISSUE

The low population densities combined with the high running costs of a fixed dental practice mean that establishing a permanent dental workforce is generally not viable in remote communities in the Kimberley. Thus there is a pressing need to explore alternative strategies to extend care to these communities. In this context, the Kimberley Dental Team (KDT), a non-government, volunteer-led organisation, was established to 'fill the gaps' and extend dental care to areas of unmet need. There is currently a lack of literature around the structure, logistics and delivery of volunteer dental services to remote communities. This paper describes the KDT, its development, resources, operational factors and organisational characteristics of the model of care, including mapping the reach of the program.

LESSONS LEARNED

This article underlines the challenges around dental service provision to remote Aboriginal communities and the evolution of a volunteer service model over the course of a decade. The structural components integral to the KDT model were identified and described. Community-based oral health promotion through initiatives such as supervised school toothbrushing programs enabled access to primary prevention for all school children. This was combined with school-based screening and triage to identify children in need of urgent care. Collaboration with community-controlled health services and cooperative use of infrastructure enabled holistic management of patients, continuity of care and increased efficiency of existing equipment. Integration with university curricula and supervised outreach placements were used to support training of dental students and attract new graduates into remote area dental practice. Supporting volunteer travel and accommodation and creating a sense of family were central to volunteer recruitment and sustained engagement. Service delivery approaches were adapted to meet community needs; a multifaceted hub-and-spoke model with mobile dental units was used to increase the reach of services. Strategic leadership through an overarching governance framework built from community consultation and steered by an external reference committee informed the model of care and its future direction.

Accuracy of mandibular repositioning surgery using new technology: Computer-aided design and manufacturing customized surgical cutting guides and fixation plates

INTRODUCTION

Recent 3-dimensional technology advancements have resulted in new techniques to improve the accuracy of intraoperative transfer. This study aimed to validate the accuracy of computer-aided design and manufacturing (CAD-CAM) customized surgical cutting guides and fixation plates on mandibular repositioning surgery performed in isolation or combined with simultaneous maxillary repositioning surgery.

METHODS

Sixty patients who underwent mandibular advancement surgery by the same surgeon were retrospectively evaluated by 3-dimensional surface-based superimposition. A 3-point coordinate system (x, y, z) was used to identify the linear and angular discrepancies between the planned movements and actual outcomes. Wilcoxon rank sum test was used to compare the outcomes between the mandible-only and the bimaxillary surgery groups with significance at P <0.05. Pearson correlation coefficient compared planned mandible advancement to the outcome from advancement planned. The centroid, which represents the mandible as a single unit, was computed from 3 landmarks, and the discrepancies were evaluated by the root mean square error (RMSE) for clinical significance set at 2 mm for linear discrepancies and 4° for angular discrepancies.

RESULTS

There was no statistically significant difference between the planned and actual position of the mandible in either group when considering absolute values of the differences. When considering raw directional data, a statistically significant difference was identified in the y-axis suggesting a tendency for under-advancement of the mandible in the bimaxillary group. The largest translational RMSE for the centroid was 0.77 mm in the sagittal dimension for the bimaxillary surgery group. The largest rotational RMSE for the centroid was 1.25° in the transverse dimension for the bimaxillary surgery group. Our results show that the precision and clinical feasibility of CAD-CAM customized surgical cutting guides and fixation plates on mandibular repositioning surgery is well within clinically acceptable parameters.

CONCLUSION

Mandibular repositioning surgery can be performed predictably and accurately with the aid of CAD-CAM customized surgical cutting guides and fixation plates with or without maxillary surgery.

Sleep-disordered breathing in children seeking orthodontic care-an Australian perspective

BACKGROUND

The prevalence of sleep-disordered breathing in children is underestimated due to impediments in detection and diagnosis. Consequently, delayed management may affect the quality of life and the growth and development of a child. Due to their patient demographic, orthodontists are optimally positioned to identify those at risk of sleep-disordered breathing and make referrals for investigation and management. This study aims to determine the prevalence of children at risk of sleep-disordered breathing in an Australian orthodontic population.

METHODS

A 1-year retrospective study was conducted in an urban Western Australian private orthodontic practice with two branches in similar socioeconomic demographics. The responses of new patients to a modified paediatric sleep questionnaire and standard medical history form were recorded.

RESULTS

In 1209 patients (4-18 years), 7.3% were at risk of sleep-disordered breathing. An association between sex and the potential risk of sleep-disordered breathing was found with 11% of males at risk of sleep-disordered breathing compared to 7% of females (P = 0.012).

CONCLUSIONS

The relatively high prevalence of children at risk of sleep-disordered breathing presenting for orthodontic care presents an opportunity to identify at-risk individuals through routine use of the paediatric sleep questionnaire. This would facilitate early referral for diagnosis and management of sleep-disordered breathing.

The predictability of expansion with Invisalign: A retrospective cohort study

INTRODUCTION

Few studies have evaluated the predictability of expansion with Invisalign for the current SmartTrack material.

METHODS

Pretreatment, predicted, and posttreatment digital models from Invisalign's ClinCheck software were obtained for 57 adult patients with a planned arch expansion of at least 3 mm. Arch width measurements were collected using a software measuring tool (MeshLab), Invisalign's arch width table, and the centroid of the clinical crown. Data for 30 patients were remeasured for each method to assess intrarater reliability. Predictability of expansion was calculated by comparing the amount of achieved expansion to predicted expansion.

RESULTS

The predictability of expansion across centroids for the maxillary teeth was: 72.2% canines, 78.9% first premolars, 81.1% second premolars, 63.5% first molars, and 41.5% second molars. The predictability of expansion across centroids for the mandibular teeth was: 82.3% canines, 93.0% first premolars, 87.7% second premolars, 79.8% first molars, and 42.9% second molars. The average expansion was significantly different from that predicted for each type of tooth in both the maxilla and mandible. Both underexpansion and overexpansion were observed. Arch width measurement reliability for each employed method was as follows: MeshLab (average error 0.197 mm); calculated centroids (0.002 mm); ClinCheck arch width table (0.000 mm).

CONCLUSIONS

On average, the amount of predicted expansion is not achieved with the Invisalign system and varies according to tooth type and arch. Discretion is required when overcorrecting to compensate for expansion inaccuracy. Both underexpansion and overexpansion were observed; further investigation into factors influencing underexpansion and overexpansion is required.

The impact of mini-implant hybrid hyrax maxillary expansion on pulp blood flow and sensibility in healthy and traumatized teeth: A prospective study

INTRODUCTION

We aimed to assess pulp blood flow (PBF) and pulp sensibility changes in healthy and traumatized teeth undergoing maxillary expansion with a mini-implant hybrid hyrax appliance.

METHODS

Forty-five patients requiring maxillary expansion either with mini-implant supported hyrax expander (MARME) or tooth-borne hyrax expander (RME) had the pulp status of their maxillary anterior teeth assessed using laser Doppler flowmetry, electric pulp testing, and thermal testing (carbon dioxide snow). The study cohort was divided into 4 groups on the basis of expansion appliance (MARME or RME) and trauma experience (trauma or nontrauma). Each patient was tested before expansion, 2 weeks after expansion, and 3 months after expansion (T3). Relationships between PBF, time interval, and trauma were evaluated using linear mixed modeling.

RESULTS

Healthy teeth with RME or MARME expansion had reestablished pretreatment PBF at T3 (P >0.05). Traumatized teeth undergoing RME did not reach pretreatment PBF at T3 (P ≤0.05). There were no statistically significant changes in PBF in the MARME+Trauma group at all time intervals (P >0.05). A reduction in pulp blood flow occurred during rapid maxillary expansion from both expansion appliances; however, the relative reduction of PBF in MARME was less than with RME (P ≤0.05) 2 weeks after expansion. Most teeth across all groups (≥85%) maintained pulp sensibility at all time intervals regardless of whether there was a history of trauma.

CONCLUSIONS

Patients with transverse discrepancies and a history of trauma may benefit from MARME as evidenced by reduced changes in PBF compared with RME without affecting pulp sensibility.

A scoping review to inform the use of continuous quality improvement in Australian Aboriginal oral health care

ObjectiveThe need to improve existing services to Aboriginal communities is prioritised by Australia's National Oral Health Plan. Although only an emerging area in dentistry, continuous quality improvement (CQI) approaches have positively impacted the delivery of primary health services to Aboriginal communities. This scoping review maps the applicability of CQI strategies to Aboriginal Australian oral healthcare services.MethodsA scoping review was conducted and studies that reported using CQI approaches to improve existing oral health services or quality of care deemed relevant to Aboriginal Australian communities were included.ResultsA total of 73 articles were retrieved and eight articles were included in the final synthesis. Several CQI tools were identified, including: plan-do-study-act cycles, dental quality alliance measures, prioritisation matrices, causal mapping and the use of collective impact methodology.ConclusionData exploring CQI in the context of Aboriginal oral health is scarce. The plan-do-study-act cycle and its variations show potential applicability to Aboriginal oral health care. However, for CQI approaches to be adequately implemented, the prevailing model of dental care requires a paradigm shift from quality assurance to quality improvement, acknowledging the impact of structural and process elements on care.

"Does this dental mob do eyes too?": perceptions and attitudes toward dental services among Aboriginal Australian adults living in remote Kimberley communities

BACKGROUND

Australian Aboriginal and Torres Strait Islander people continue to experience significant disparities in oral health and there remains an urgent need to improve services to rural and remote communities. Quantitative research has typically been used to highlight the disease burden and severity experienced by those living in remote communities, but this data does little to explore the lived reality and psychosocial nuances that impact on care. The Kimberley region of Western Australia is home to over 150 Aboriginal communities spread out across 400,000 square kilometres. The success and sustainability of oral health services to these remote communities relies on respect and reciprocity achieved through shared knowledge, decision making and involvement of Aboriginal people in discussions around oral health services and their delivery. This, study aimed to investigate the perceptions and attitudes toward dental services among Aboriginal Australian families living in remote Kimberley communities.

METHODS

Semi-structured interviews and yarning circles were carried out following purposive sampling of Aboriginal adults living in the East Kimberley region of Western Australia. Interviews were recorded, transcribed, and analysed guided by a constructivist grounded theory approach.

RESULTS

In total, 80 community members participated in the yarning process. Enablers to care included: promotion of existing services, integration with primary health services, using mobile dental services and volunteers to extend care. Barriers to care included transportation, cost of treatment, the complexity of appointment systems and shame associated with health-seeking behaviours.

CONCLUSIONS

Reassessing the prevailing operative model of dental care to remote Aboriginal communities is warranted to better address the overwhelming structural barriers that impact on oral health. Integration with existing primary health services and schools, the use of mobile units to extend care and increasing community engagement through clinical yarning are recommended in improving the current state of dental services to communities in the Kimberley.

Oral health education and prevention strategies among remote Aboriginal communities: a qualitative study

BACKGROUND

The delivery of effective oral health promotion strategies is essential to improving oral health outcomes among remote Aboriginal communities. This study aimed to explore the perceptions and attitudes of Aboriginal Australians living in remote Kimberley communities towards oral health education and disease prevention.

METHODS

Semi-structured interviews and yarning circles were carried out following purposive sampling of Aboriginal adults living in the East Kimberley region of Western Australia.

RESULTS

A total of 80 community members participated in the yarning process. School-based oral health promotion and community-driven restrictions on the sale of sugary food and drink were seen as positive strategies in improving oral health. Lifestyle changes brought about by modernity, internet availability and fixed community stores were perceived to create new challenges and shift the priorities for those living in remote communities.

CONCLUSIONS

Community-based yarning may better inform future oral health strategies in the Kimberley. A neoliberal approach of shifting responsibility onto the individual ignores the complex social inequities faced by Aboriginal people living in remote communities where macro-level determinants such as remoteness, food security and education significantly influence decisions around diet and oral health.

Trends in orthodontic management strategies for patients with congenitally missing lateral incisors and premolars

OBJECTIVES

To identify changes in orthodontic management strategies in patients with hypodontia seen in 2000, 2010, and 2017/2018 (during a 1-year period).

MATERIALS AND METHODS

An assessment of the panoramic radiographs of 3701 patients from a Western Australian private practice identified 276 individuals demonstrating hypodontia. The location of missing teeth, age, sex, type of malocclusion, and the management strategies (space closure or opening) for each patient were noted.

RESULTS

Most hypodontia involved agenesis of three or fewer teeth (90%). Maxillary lateral incisors and mandibular second premolars were the most commonly missing teeth. Female preponderance was noted. When considering treatment, the odds ratio for orthodontic space opening and prosthetic replacement in 2000 was 3.266 (P value = 7e-04; 95% confidence interval [CI], 1.464-4.633) compared with patients seen in 2010 and 1.632 (P value = 7e-04; 95% CI, 0.811-2.434) compared with patients in 2017/2018. For patients demonstrating bilateral absence of maxillary lateral incisors, the odds ratio for orthodontic space opening was 3.185 (P value = 0.0215; 95% CI, 1.182-9.243) compared with counterparts with unilateral agenesis. None of the factors investigated were significantly associated with the types of treatment planned/provided for the patients with missing mandibular second premolars.

CONCLUSIONS

Maxillary lateral incisors and mandibular second premolars were the most commonly missing teeth. A trend away from space opening and prosthetic replacement toward orthodontic space closure was observed from 2000 to 2017/2018. This may reflect a change in attitude toward prosthetic replacement options and/or greater optimism with biomechanical strategies since the implementation of temporary anchorage devices to assist in space closure.

Accuracy of mandibular proximal segment position using virtual surgical planning and custom osteosynthesis plates

The purpose of this study was to determine whether the use of custom osteosynthesis plates increased the accuracy of proximal segment position following bilateral sagittal split osteotomy in a cohort of 30 patients when compared to a control group of 25 patients who had surgery with conventional plates. Surgery was performed by a single surgeon between October 2015 and December 2017. Post-surgical cone beam computed tomography scans were segmented using Mimics Innovation Suite (Materialise NV), and surface-based superimposition was achieved using ProPlan CMF (Materialise NV). However, there was a tendency for the rotational error to be smaller in the custom group than in the control group. The root mean square error in both groups and for all variables fell within clinical parameters of 2 mm and 4°. In conclusion, the results of this study indicate that customized mandibular fixation plates do not necessarily improve the accuracy of the proximal segments post-surgically; however they may be of benefit in individual patients.

Occupational Eye Trauma: a major public health issue in France

Occupational Eye Trauma (OET) is a global cause of visual morbidity. According to the WHO, 55 million ocular lesions occur each year, and 1.6 million cases of total blindness caused by trauma. The objective of our work is to evaluate the frequency of OET per projectile in France, to compare results to other similar studies, and therefore to encourage the reinforcement of safety measures. This is a cross-sectional descriptive study, carried out in the Ophthalmic Emergency Department, at the Intercommunal Hospital of Villeneuve-Saint-Georges, France, including all patients who presented to the same doctor's consultation, between June 2019 and December 2019.

The study involved 1730 patients, 700 women and 1030 men, with an average age of 40. In 7 months, 600 are victims of ocular trauma and 346 are victims of projectile during professional practice, a prevalence of 20% of all emergencies, or 57% of all trauma. The prevalence is higher within males, reaching 33% of all emergencies. The average age was 39, 99% of males. The average consultation time was 3 days after the accident. Besides, 66% of consultants already have a previous history of OET; and 59% were not using a safety protection.

The study shows that 58% of patients had a corneal foreign body; 25% a corneal ulcer; 10% a conjunctival foreign body; while 2 cases (0.5%) presented a corneal wound requiring surgical management. Therefore, eye trauma is a real public health problem. They account for 35% of consultations, half of which are associated with professional activities, mainly affecting young and active men. The high rate of recidivism and non-respect of safety measures highlights the lack of awareness of the target population. Compared to the findings of a previous study lead in Morocco, the outcomes are almost identical, 20/18% in prevalence, 66/75% in recidivism.

Results of this work shows that OET, avoidable circumstances, are however frequent, causing potential severe lesions, with a reserved prognosis.

Key messages

The results of this work prove that occupational ocular trauma, avoidable circumstances, are however frequent. Workplaces with a high risk of eye trauma should strengthen their protective measures and training programs should be put in place for both workers and occupational physicians.

Pulp blood flow and sensibility in patients with a history of dental trauma undergoing maxillary expansion

OBJECTIVES

To assess changes in pulp blood flow (PBF) and pulp sensibility (PS) in teeth of patients with a history of dental trauma undergoing maxillary expansion.

MATERIALS AND METHODS

Twenty-five patients requiring rapid maxillary expansion (RME) had the pulp status of their maxillary anterior teeth assessed using laser Doppler flowmetry, electric pulp testing, and thermal testing (CO2 snow). Each patient was tested at T1 (prior to expansion), T2 (2 weeks after rapid expansion), and T3 (3 months after expansion). Relationships between PBF, time interval, and history of trauma were evaluated using linear mixed modelling.

RESULTS

Within the Trauma group, PBF was significantly lower (P ≤ .05) at T2 and T3 in comparison to T1 and significantly lower (P ≤ .05) at T2 in comparison to T3. In the Non-trauma group, PBF at T2 was significantly lower (P ≤ .05) than PBF at T1 and T3; however, no significant difference (P > .05) in PBF was observed when comparing PBF at T1 and T3. In both groups, PS was maintained in almost all teeth (>90%).

CONCLUSIONS

RME in healthy teeth causes reduction of PBF before reestablishment of pretreatment values. RME in traumatized teeth causes reduction of PBF without PBF being reestablished to pretreatment levels. Teeth with a history of compromise may have reduced adaptive capacity under insults such as RME, which should be appreciated during the informed consent process.

Trends in surgical-orthodontic management of Class III malocclusions in Western Australia

Aim

The aim of this retrospective cohort study was to identify trends in the surgical-orthodontic management of skeletal Class III malocclusions in Western Australia between 1985 and 2016.

Methods

The records of 225 patients (132 females, 93 males) who received combined surgical-orthodontic correction of their Class III malocclusion between 1985 and 2016 were retrospectively assessed. The subjects were divided into three groups according to surgery type: Group (1) maxillary advancement only; Group (2) mandibular setback only; Group (3) two-jaw surgery.

Results

A trend towards two-jaw surgery for Class III correction was observed. Between 1985 and 2016, 123 patients (55%) were treated via two-jaw surgery; 97 patients (43%) were treated via maxillary advancement alone and five patients (2%) were treated via mandibular setback alone. Between 2011 and 2016, 61% were treated via two-jaw surgery; 37% were treated via maxillary advancement surgery; 2% were treated via mandibular setback surgery. Gender affected surgery type: two-jaw surgery (60% female); maxillary advancement (62% female); mandibular setback (17% female). A greater proportion of females received Class III surgical management in comparison with males (59:41).

Conclusion

Two-jaw surgery is the most common procedure for the surgical correction of skeletal Class III malocclusions in Western Australia. Of the single jaw procedures, isolated maxillary advancement surgery is more common than mandibular setback procedures.

Enabling Aboriginal dental assistants to apply fluoride varnish for school children in communities with a high Aboriginal population in New South Wales, Australia: a study protocol for a feasibility study

Background

Australian Aboriginal children experience high levels of dental caries (tooth decay) and are less likely to access preventive dental health services. High-strength fluoride varnish has been shown to reduce the incidence of dental caries and is commonly used in community-based preventive dental health service programs. In New South Wales, Australia, the application of fluoride varnish is restricted to dental and medical professionals. This is problematic in communities with a high Aboriginal population and limited access to oral health services, contributing to the increased risk of developing dental caries in Aboriginal children. Dental assistants are essential members of the oral health team; however, they do not have a defined scope of practice in Australia. Other countries have created formal scopes of practice for dental assistants to include the application of fluoride varnish. This protocol presents a pathway for qualified Aboriginal dental assistants to undertake additional training to legally apply fluoride varnish in New South Wales. The primary objective of this study will be to evaluate the feasibility and acceptability of utilising Aboriginal dental assistants to apply fluoride varnish to Aboriginal children in a school setting at regular 3-month intervals.

Methods

Six schools across New South Wales (NSW) that enrol at least 12% Aboriginal children will be invited to participate in the 12-month study. Aboriginal children aged 5–12 years enrolled in these schools will be enrolled in the study. Six Aboriginal dental assistants will undertake training to apply fluoride varnish. Fluoride varnish (Duraphat) will be applied at 3-month intervals by the dental assistants to the teeth using a small brush. An evaluation will be undertaken to determine the feasibility and cost-effectiveness of this innovative approach. This study protocol has been approved by the NSW Aboriginal Health and Medical Research Council and the NSW State Education Research Application Process.

Discussion

A qualified Aboriginal dental assistant workforce in NSW (or Australia) legally approved to apply fluoride varnish may increase the sustainability and scalability of fluoride varnish programs and improve the oral health of Aboriginal children in Australia.

Trial registration

ISRCTN26746753.

Electronic supplementary material

The online version of this article (10.1186/s40814-019-0399-4) contains supplementary material, which is available to authorized users.

Fluoride release, recharge and mechanical property stability of various fluoride-containing resin composites

AIM

To determine the fluoride release and recharge of three fluoride-containing resin composites when aged in deionized water (pH 6.5) and lactic acid (pH 4.0) and to assess mechanical properties of these composites following aging.

METHODS

Three fluoride-containing resin composites were analyzed in this study; a new giomer material named Beautifil II, Gradia Direct X, and Tetric EvoCeram. A glass ionomer cement, Fuji IX Extra, was also analyzed for comparison. Specimens were fabricated for two test groups: group 1 included 10 disc specimens initially aged 43 days in deionized water (five specimens) and lactic acid (five specimens). The fluoride release from these specimens was measured using a fluoride-specific electrode on nine specific test days during the aging period. Following 49 days of aging, each specimen was recharged in 5000 ppm neutral sodium fluoride solution for 5 minutes. Specimen recharge was then repeated on a weekly basis for 3 weeks. The subsequent fluoride rerelease was measured at 1, 3, and 7 days after each recharge episode. Group 2 included six disc specimens aged for 3 months in deionized water (three specimens) and lactic acid (three specimens). The hardness and elastic modulus of each specimen was measured using nano-indentation at intervals of 24 hours, 1 month, and 3 months after fabrication. Two-way factorial analysis of variance (ANOVA) and post-hoc (Tukey) testing was used to assess the influence of storage media (two levels) and composite type (three levels) on the fluoride release, fluoride rerelease, hardness, and elastic modulus of the assessed materials. The level of significance was set at p=0.05.

RESULTS

All three composites demonstrated fluoride release and recharge when aged in both deionized water and lactic acid. The cumulative fluoride released from Beautifil II into both media was substantially greater than the fluoride released from Gradia Direct X and Tetric EvoCeram after 43 days aging and was significantly (p<0.05, ANOVA, Tukey test) greater during several analysis periods. Beautifil II demonstrated the greatest recharge ability of the three composites over the 3-week recharge period in both media. Fuji IX Extra demonstrated a significantly (p<0.05) greater fluoride release and recharge compared with the three resin composites. The elastic modulus and hardness of the three composites did not decrease significantly (p<0.05) with fluoride release or fluid uptake over the 3-month aging period, in either media.

CONCLUSION

The three composites in the present study demonstrated fluoride release (Beautiful II > Gradia Direct X > Tetric EvoCeram) and fluoride recharge (Beautiful II > Gradia Direct X > Tetric EvoCeram). This capability raises the possibility of fluoride-containing composites exhibiting a lower incidence of recurrent caries than non fluoride–containing composites. The mechanical properties of each composite did not diminish with aging and fluoride release over the testing period.