• Open Access

Description of comprehensive dental services supported by the Medicare Chronic Disease Dental Scheme in the first 23 months of operation

Authors


Correspondence to: Hans Zoellner, Oral Pathology and Oral Medicine, The Faculty of Dentistry, The University of Sydney, Westmead Centre for Oral Health, Westmead Hospital, Westmead, NSW 2145; e-mail: hans.zoellner@sydney.edu.au

Abstract

Objective: Australia's Medicare universal insurance system has supported comprehensive dental service through the Chronic Disease Dental Scheme (CDDS) since November 2007. Public debate opposing CDDS includes claims of over-servicing, calls for expansion to universal eligibility, and government threat of closure. Here we examine CDDS services over the first 23 months of operation.

Methods: CDDS statistics on patient age, gender and item numbers claimed from November 2007 to December 2009 from Medicare were subjected to analysis.

Results: The distribution of 404,768 total CDDS patients varied across Australia from 3.6% of the population in NSW to 0.07% in NT, while uptake increased over time. The average patient had 7.58 dental treatments, and the most common were: direct restorations (2.27), preventive and periodontal services (1.46), diagnostic services (1.43), extractions (0.77), and new dentures (0.53). Crown and bridgework appeared over-represented (0.48).

Conclusion: Although data do suggest over-servicing in crown and bridgework, there also appears to be significant community need for the CDDS.

Implication: Clear guidelines for dental clinical diagnosis and treatment planning, as well as a pre-approval process for crown and bridgework is suggested to improve the CDDS, and this could form the basis for expansion to universal eligibility for dental Medicare.

There is evidence for association between dental infection and several systemic conditions including: central and peripheral vascular disease, diabetes, poor birth outcomes and aspiration pneumonia.1–6 Although mechanisms are unclear, some animal and human intervention studies suggest a causative contribution of oral infection to these systemic conditions,2,7–14 so that improved control of dental infection may reduce the burden of separate systemic disease. Dental infection also contributes substantially to preventable hospitalisation.15,16 Despite these broad health implications, dental services are not included in Australia's Medicare universal health insurance system, and the cost of private dental services significantly limits access.17

In November 2007 the Enhanced Primary Care Dental Initiative, which provided limited dental funding, was expanded to become the Medicare Chronic Disease Dental Scheme (CDDS). Under the CDDS, eligible patients may receive Medicare benefits of up to $4,250 for eligible services provided under the CDDS during two consecutive calendar years. Eligibility for CDDS is determined by general medical practitioners, who identify the presence of a chronic systemic disease that may be adversely affected by the patient's dental condition. Medical practitioners are required to prepare multidisciplinary care plans including dental treatment, in order for patients to access the CDDS.

Although the Federal Government elected in December 2007 indicated cessation of CDDS, the scheme has continued with the support of the Senate. The public availability of data on CDDS service provision provides an unprecedented opportunity to examine patterns of private dental service heavily subsidised by the Australian Federal Government via Medicare.

A brief review of common dental disease and treatment is necessary. Caries involves bacterial invasion and destruction of tooth structure, and is treated by removal of infected tissue followed by ‘filling’ with dental restorations. In untreated caries, bacteria invade the vascular dental pulp with an eventual spread to bone at the root apex (Figure 1). The spread of infection to soft tissues may be followed by life-threatening sepsis. Restorations may be either direct into teeth, or alternatively ‘indirect restorations’ cemented into place after preparation using plaster models. Direct restorations may be of amalgam, mostly used in posterior teeth, or of adhesive tooth-coloured material. Although adhesive materials are aesthetically pleasing, amalgam has greater longevity.18,19 When tooth structure is severely compromised, it becomes necessary to ‘cut the tooth back’ to a thimble shape to accept indirectly prepared crowns enclosing the entire tooth surface (Figure 1). Inlays are smaller indirect restorations of gold or porcelain. Most restorations eventually require replacement accompanied by additional loss of tooth structure, so that a conservative approach is preferred. If caries infection has spread to the pulp or bone, the tooth must either be extracted, or an endodontic procedure performed to remove infected dental pulp and obturate the pulp chamber with a ‘root canal filling’ (Figure 1).

Figure 1.

Diagrams illustrating: spread of caries infection to apical bone via the pulp; the 5 separate tooth surfaces susceptible to disease; a three surface restoration; osseointegrated implants; a bridge pontic; crowns; and the typical thimble-shaped preparation of a natural tooth needed to make a crown.

In periodontitis, irritant plaque destroys the periodontal ligament and bony tooth support with eventual tooth loss. Treatment includes improved oral hygiene, curettage, and surgical tissue remodelling.

When only some teeth are lost, they may be replaced using either bridges or partial dentures. A bridge consists of a false tooth ‘pontic’ held in place by two crowns on either side of the offending gap. While bridges are permanently cemented into place, partial dentures are removable and fixed by clasps grasping natural teeth. Denture clasps may be part of a cast metal framework, or alternatively just wires embedded in a resin base. Partial dentures with a cast metal framework are generally preferred over those with an acrylic base because of greater comfort and longevity. While any ill-fitting partial denture may traumatise gingiva and act as a plaque and food trap, these problems seem less pronounced when cast metal frameworks rather than acrylic bases are used.

When all teeth are lost, replacement is with a full denture. Osseointegrated implants may be used to anchor full dentures, partial dentures and also crowns or bridges.20

General dental practitioners and specialists deliver the full range of dental services, while prosthetists with dental technician background and additional clinical training are able to make dentures and denture repairs.

There has been public discussion of possible over-servicing in the CDDS,21–23 while the federally appointed National Health and Hospital Commission recently recommended a separate universal dental health insurance program,24,25 and the Greens political party has announced a policy of expanding the CDDS to include the entire population.26,27 This study aims to describe patterns of service delivered under the CDDS over the first 23 months of implementation, both in light of and to inform public discussion.

Methods

Collection of data

Data on services defined by specific item numbers between November 2007 and December 2009 was from the Medicare website (http://www.medicareaustralia.gov.au). Table 1 shows the item numbers used and grouped for analysis in this study. Item numbers were selected to avoid double counting, as item numbers for services intermediate in the restoration or root canal – endodontic therapy of individual teeth were excluded from the analysis, as were item numbers for intermediate steps or components of prosthetic, surgical and preventive services. Item numbers were grouped to facilitate analysis of treatment type, and were indicative of the number of: diagnostic; preventive and periodontal; extraction; general surgical; acute pain and dental emergency; chronic pain management; endodontic; direct restorative; indirect restorative; bridge; implant; orthodontic; denture; and denture repair services on a per tooth or patient basis. The Medicare website provides data using a similar but less comprehensive grouping, which has the disadvantage of ‘double counting’ on a per tooth or patient basis, but is nonetheless more helpful with regard to determining the total cost of treatment. For this reason, where costs are compared in the current study, these data were obtained directly from the Medicare website according to the grouping used by Medicare. Patient number was estimated from those item numbers used for diagnostic examination, while the study was limited to the first 23 months of the CDDS to minimise the likelihood of including patients returning after an initial course of care for maintenance therapy.

Table 1.  Medicare Item Numbers used for analysis grouped according to the type of service delivered (X- is 85- for general dental practitioners, 86- for specialist dental practitioners, and 87- for prosthetist delivered services).
Item No. SuffixTreatment Description
Patients Treated 
X-011, X-012, X-013, X-014, X-015Comprehensive, Periodic, and Limited (Emergency) Oral Examination, and Consultations
Diagnostic Services
X-022, X-025, X-031, X-035, X-036,
X-037, X-038, X-039, X-051
Intraoral, Extraoral, Temporomandibular Joint, Cephalometric, Panoramic, Hand-Wrist and Skull Tomographic Radiology, and Biopsies
Preventive and Periodontal Services
X-047, X-111, X-113, X-114, X-115,
X-117, X-121, X-123, X-131, X-141,
X-161, X-171, X-221, X-222, X-225,
X-231, X-232, X-233, X-234, X-235,
X-236, X-238, X-241, X-245
Caries Activity Testing, Scaling, Cleaning, Recontouring Restorations, Internal Bleaching, Remineralisation, Dietary Advice, Oral Hygiene Instruction, Fissure Sealing, Odontoplasty, Periodontal Recording, Root Planing and Curetage, Non-Surgical Periodontal Therapy, Soft Tissue and Bone Surgical Periodontal Therapy Including Grafts and Gingivectomy
Extractions 
X-311, X-314, X-316, X-322, X-323,
X-324, X-326
Simple, Sectional and Surgical Extractions Including Removal of Root Fragments and Bone
General Surgical Procedures
X-331, X-332, X-337, X-338, X-341,
X-343, X-344, X-345, X-371, X-373,
X-375, X-376, X-377, X-378, X-379, X-381, X-382, X-384, X-385, X-388, X-389, X-391, X-393, X-395
Bone and Soft Tissue Plastic Surgery including Grafts and Hyperplastic Tissue, Repositioning Muscle Attachment, Cysts and Tumours, Removal of Scars, Salivary Duct and Gland Surgery, Removal of Foreign Bodies, Cyst Marsupialisation, Surgical Exposure and Ligation of Teeth, Repositioning Teeth, Transplantation of Teeth or Tooth Bud, Isolation and Preservation of Neurovascular Tissue, and Surgery Involving the Maxillary Antrum
Acute Pain and Dental Emergencies
X-213, X-386, X-387, X-392, X-412, X-419, X-911, X-927, X-986Acute Periodontal Infection, Splinting Displaced Teeth, Drainage of Abscess, Endodontic Emergency, Palliative Care, Prescription
Chronic Pain Management 
X-165, X-394, X-926, X-965, X-966,
X-968, X-971, X-972, X-981
Desensitisation, Surgery for Osteomyelitis, Occlusal Splint and Adjustment, Physiotherapy, Splinting and Stabilisation
Endodontic Services 
X-414, X-417, X-431, X-432, X-433,
X-434, X-436, X-437, X-438, X-457
Pulpotomy, Peri-Radicular Surgery and Apicectomy, Apical Seal, Treatment of Perforation and Resorption
Direct Restorations (Amalgam and Adhesive)
X-511 to 5, X-521 to 5, X-531 to 5,
X-576
Posterior Amalgams, Posterior Adhesive and Anterior Adhesive Restorations with from 1 to 5 Surfaces, and Stainless Steel Crowns
Indirect Restorations (Crowns and Inlays)
X-541 to 5, X-551 to 5, X-613,
X-615, X-618
Indirect Inlays with 1 to 5 Surfaces, and Crowns (Metal, Porcelain, Veneered)
Bridge Pontics 
X-642, X-643Pontics for Bridges (For Analysis 2 Crowns are Assumed Needed Per Pontic)
Osseointegrated Implants 
X-661, X-664, X-666, X-671, X-672,
X-673, X-684, X-688
Implant Abbutments, Bars and Crowns Attached to Implants, Two and One Stage Implants
Orthodontic Services 
X-811, X-821, X-823, X-829, X-831Removable and Fixed Appliances, Partial and Full Banding
Dentures 
X-711, X-712, X-719, X-721, X-722,
X-727, X-728
Full Dentures, Partial Resin Dentures, and Partial Metal Framework Dentures
Denture Repairs 
X-741, X-743, X-744, X-745, X-746,
X-751, X-752, X-753, X-761, X-762,
X-763, X-764, X-765, X-767, X-768,
X-769
Adjustment, Relining, Remodelling, Cleaning and Polishing, Reattaching and Replacing Teeth and Clasps, Repairing Broken Base, and Adding Teeth
The item numbers selected for analysis provide information at the level of services per tooth (extractions, endodontic services, direct restorations, indirect restorations) or per patient (diagnostic services, preventive and periodontal services, general surgical procedures, acute pain and dental emergencies, chronic pain management, bridge pontics, osseointegrated implants, orthodontic services, dentures, and denture repairs). The range of dental services supported by the CDDS is extensive and permits comprehensive dental care of patients

Statistical analysis

Statistical analysis assessed data from those who have accessed CDDS services with reference to the wider population who are eligible, but who may not have not used the scheme. The chi-square test was used to evaluate the statistical significance of differences in proportion between groups,28 and binomial analysis of proportion by approximation was applied in considering single statistics using the calculator available at http://faculty.vassar.edu/lowry/binomialX.html, assuming an expected proportion of 0.5. Confidence intervals (CI) are indicated at the 95% level and were calculated without correction for continuity.

Results

The distribution of CDDS patients across Australia

The total number of CDDS patients treated as well as the number of discrete treatments according to type is shown in Table 2. Of the Australian population, 1.8% accessed CDDS, although this varied between state jurisdictions ranging from a maximum of 3.6% of the New South Wales (NSW) population to 1.8% in Victoria; 1.4% in South Australia (SA); 0.57% in Queensland; 0.34% in the Australian Capital Territory (ACT); 0.28% in Tasmania; 0.08% in Western Australia (WA); and 0.07% in the Northern Territory (NT), with differences all statistically significant to p<0.001 with the exception of that between WA and NT. A separate table showing state-level data is available at the University of Sydney website (http://hdl.handle.net/2123/7744).

Table 2.  The number of CDDS supported patients and services according to treatment type.
 General dental practitioner servicesSpecialist servicesProsthetist servicesTotal services for all practitioners
  1. The majority of CDDS patients were seen by general dental practitioners only, although prosthetists and dental specialist practitioners also provided an appreciable number of services.

Patients treated
Services
95% CI
352,298
351,879–352,717
6,282
6,128–6,436
46,188
45,792–46,584
404,768-
Diagnostic services
Services
95% CI
568,015
566,682–569,348
9,122
8,935–9,309
 577,137
575,795–578,479
Preventive and periodontal services
Services
95% CI
581,224
579,879–582,569
8,456
8,276–8,636
 589,680
588,327–591,033
Extractions
Services
95% CI
305,281
304,253–306,309
6,587
6,428–6,746
 311,868
310,831–312,905
General surgical procedures
Services
95% CI
4,958
4,820–5,096
338
302–374
 5,296
5,153–5,439
Acute pain and dental emergencies
Services
95% CI
48,361
47,933–48,789
362
325–399
 48,723
48,294–49,152
Chronic pain management
Services
95% CI
23,677
23,377–23,977
388
349–427
 24,065
23,762–24,368
Endodontic Services
Services
95% CI
44,992
44,579–45,405
1,344
1,272–1,416
 46,336
45,917–46,755
Direct restorations (amalgam and adhesive)
Services
95% CI
916,834
915,262–918,406
1,631
1,552–1,710
 918,465
916,893–920,037
Indirect restorations (crowns and inlays)
Services
95% CI
193,261
192,427–194,095
293
259–327
 193,554
192,719–194,389
Bridge pontics
Services
95% CI
41,295
40,899–41,691
47
34–60
 41,342
40,946–41,738
Osseointegrated implants
Services
95% CI
2,657
2,556–2,758
1,559
1,482–1,636
 4,216
4,089–4,343
Orthodontic services
Services
95% CI
1,977
1,890–2,064
934
874–994
 2,911
2,805–3,017
Dentures
Services
95% CI
158,767
158,007–159,527
459
417–501
56,998
56,534–57,462
216,224
215,345–217,103
Denture repairs
Services
95% CI
62,960
62,473–63,447
239
209–269
25,281
24,971–25,591
88,480
87,905–89,055
Total number of individual procedures performed, per tooth – patient basis
Services
95% CI
2,954,259
2,953,610–2,954,908
31,759
31,412–32,106
 3,068,297

The rate of CDDS uptake significantly increased towards the end of the study period (Figure 2). While the absolute percentage of state population using CDDS in the month of December 2009 in WA and NT remained much lower than all other states (0.006% and 0.008% respectively, p<0.001), there was increased use in Tasmania (0.02%), ACT (0.03%), Queensland (0.06%), Victoria (0.14%), and SA (0.15%) (p<0.05), and NSW residents had the highest percentage population use of CDDS per month at the end of the study period (0.21%) (p<0.001). Of note is a brief dip in CDDS use from April to June 2008.

Figure 2.

Graph showing the percentage of total state, territory or national population undergoing dental examination in the CDDS per month from November 2007 to December 2009. There was steadily increasing use of the CDDS, although uptake varied greatly between jurisdictions.

The age and gender of CDDS patients

Figure 3 illustrates the number of CDDS patients according to age group, gender and whether seen by prosthetists or dentists. More women were treated than men by both prosthetists and dentists (p<0.001), while dentists treated substantially more patients compared with prosthetists (p<0.001) (Table 2, Figure 3). Although most patients were over the age of 54 (p<0.001), and prosthetists treated an older cohort compared with dentists (p<0.001), 1,449 patients were under the age of 15.

Figure 3.

Histograms showing the number of patients treated by prosthetists as well as by general and specialist dental practitioners combined, according to age and sex. There was a slight female preponderance amongst patients in the CDDS, while patients seen by dentists were generally younger than those seen by prosthetists.

Patterns of service delivered under the CDDS

Similar patterns of treatment were seen across states and territories (data available at the University of Sydney website, http://hdl.handle.net/2123/7744). Of 7.580 average dental treatments per patient across Australia, the most common services were: direct restorations (2.269, 95% CI 2.265–2.273); preventive and periodontal services (1.457, 95% CI 1.455–1.462); diagnostic services (1.426, 95% CI 1.422–1.429); extractions (0.770, 95% CI 0.768–0.773); new dentures (0.534, 95% CI 0.532–0.536); and indirect restorations (0.478, 95% CI 0.476–0.480).

Among all restorations placed, there were proportionately more direct (82.6%, 95% CI 82.5–82.7) than indirect restorations (p<0.001) (Table 3). Comparing jurisdictions, however, while NSW (20.0%, 95% CI 19.9–20.1) and Tasmania (18.9%, 95% CI 17.6–20.2) had comparable rates of indirect restorations, these two states delivered proportionately more indirect restorations compared with other states and territories considered together (12.7%, 95% CI 12.6–12.8) (p<0.001, data available at the University of Sydney website, http://hdl.handle.net/2123/7744) where the proportion ranged from 16% in WA to 5% in NT. Separately, there were proportionately more crowns related to bridges in NSW and Victoria (43.9% of crowns, 95% CI 43.6–44.2), than in other states considered together (31.2% of crowns, 95% CI 30.5–31.9) (p<0.001, data available at the University of Sydney website, http://hdl.handle.net/2123/7744). Adhesive materials were used in the great majority of posterior restorations (92.1%, 95% CI 92.0–92.2) in preference to amalgam (p<0.001). Oral hygiene instruction was delivered to only 59,374 patients comprising 14.7% of all patients (95% CI 14.6–14.8). Most patients receiving dentures required partial (66.4%, 95% CI 66.2–66.6) as opposed to full dentures (p<0.001), while 68.0 % of full dentures (95% CI 67.6–68.4) and 45.2% of partial dentures (95% CI 44.9–45.5) were for the upper jaw (p<0.001). The great majority of partial dentures made had cast metal frameworks (81.4%, 95% CI 81.2–81.6) as opposed to resin bases (p<0.001).

Table 3.  The average number of CDDS services per patient according to type of service delivered, expressed as both services per patient and the relative percentage of services per patient.
 Services per patient95% CIRelative % of services95% CI
  1. The average CDDS patient received a wide range of routine and advanced dental services consistent with a backlog of untreated dental disease.

Diagnostic services1.4261.423 – 1.42918.80218.758 – 18.846
Preventive and periodontal services1.4591.456 – 1.46219.23719.193 – 19.281
Extractions0.7700.767 – 0.77310.16210.128 – 10.196
General surgical procedures0.0130.012 – 0.0140.1750.170 – 0.180
Acute pain and dental emergencies0.1200.119 – 0.1211.5881.574 – 1.602
Chronic pain management0.0590.058 – 00600.7840.774 – 0.794
Endodontic services0.1140.113 – 0.1151.5101.496 – 1.524
Direct restorations (amalgam and adhesive)2.2692.265 – 2.27329.92729.876 – 29.978
Indirect restorations (crowns and inlays)0.4780.476 – 0.4806.3076.280 – 6.334
Bridge pontics0.1020.101 – 0.1031.3471.341 – 1.353
Osseointegrated implants0.0100.009 – 0.0110.1370.133 – 0.141
Orthodontic services0.0070.006 – 0.0080.0950.092 – 0.098
Dentures0.5340.532 – 0.5367.0457.016 – 7.074
Denture repairs0.2190.218 – 0.2222.8832.864 – 2.902
Total number of individual procedures performed on a per tooth – patient basis7.582100.000

The cost of CDDS services

Total expenditure from November 2007 to December 2009 was $731,907,788, with an average expenditure per patient of $1,808. Considering the percentage of total expenditure according to treatment type, denture services (33.88%, CI ± 0.01%) accounted for the largest proportion of cost, followed by crown and bridge (30.32%, CI ± 0.01%), direct restorative (16.33%, CI ± 0.01%), diagnostic (4.94%, CI ± 0.01%), oral surgical (4.76%, CI ± 0.01%), endodontic (3.66%, CI ± 0.01%), preventive (2.80%, CI ± 0.01%), periodontic (2.20%, CI ± 0.01%), general (0.76%, CI ± 0.01%), and orthodontic (0.35%, CI ± 0.01%) services.

Discussion

There are recent reports of patterns of private dental service in Australia,29–31 but these suffer from the necessary sampling limitations of mail surveys to busy clinicians. The data readily extracted on CDDS services, however, provides a patient sample size and level of detailed information on precise treatments delivered, which appears unprecedented for Australian private dental practice. The current study is only of clinicians and patients participating in the CDDS, so conclusions about patterns of private dental practice can not be readily made regarding wider practice beyond the scheme. Nonetheless, the current study does illustrate the potential power of Medicare records for analysis and practice monitoring, were the CDDS expanded to eventually include all citizens. Some over-estimation of patient numbers is likely in the current study, because many patients presenting to specialist dental clinicians will have also attended general dental surgeries. However, the comparatively small number of diagnostic examinations by specialists suggests the effect of this is negligible. Also, it is impossible to determine from the available statistics what proportion of patients presenting to prosthetists also attended general or specialist dental practitioners, but any ‘double counting’ effect of this is likely to be small because prosthetist patients comprised only 11% of total patients served. Most preventive services such as fluoride application, scaling teeth and oral hygiene instruction at least partly reverse existing disease and also prevent new lesions from arising. Separately, many operative dental procedures such as restorations and endodontic services simultaneously manage current disease and rehabilitate oral function. To facilitate numerical analysis in the current study, we have sought to avoid possible ambiguity by classifying treatment with primary regard to the operative service delivered, rather than with reference to the potentially preventive, disease management or rehabilitative overall clinical objectives. Unfortunately, data available through the Medicare Australia Website permits only determination of the mean number of services per patient, and not the specific proportion of patients who received any given treatment. We are, however, hopeful that the more detailed data needed to evaluate the distribution of services across the patient population may be made available by Medicare at some future time.

It is interesting to observe patterns of uptake of the CDDS across state and territory jurisdictions. Because of government intentions to discontinue CDDS services, there has been no formal advertising to the target population with chronic systemic disease of their eligibility. We speculate that the much higher uptake in NSW relative to other states reflects the combined effect of local CDDS promotion by a NSW-based oral health advocacy group (The Association for the Promotion of Oral Health) via local community groups, as well as active advice from NSW Health to potentially eligible patients to seek CDDS services. There was a marked reduction in new CDDS patients in May and June 2008 across all state and territory jurisdictions, followed by a steep growth in uptake of the scheme. The brief fall in patient numbers seems due to Federal Government announcements and letters to health professionals, enrolled patients and the media that the CDDS was closing, although subsequent Senate action prevented this from happening. It has been argued that the CDDS does not benefit children,32 however, since comparatively few children suffer chronic systemic disease it is not surprising that the CDDS benefits mostly older people. It should be noted that children with chronic disease are also eligible for CDDS support and the current data indicate use of this scheme in such circumstances.

Data are consistent with a significant burden of untreated dental disease in CDDS patients, but in the absence of data on individual patients, it is impossible to be confident that services delivered were all appropriate to patient need. Indirect restorations including bridges do, at first sight, appear over-represented, and also account for a significant proportion of cost. Regulation of CDDS via a pre-approval process for crown and bridge services would seem reasonable to ensure these services are all clinically appropriate. Importantly, similar regulation has proven effective in dental services supported by the Department of Veteran's Affairs. Despite the high cost of indirect restorative procedures, we see that many teeth would be lost without such service and that any savings would be eroded by the further cost of replacement. In addition, we argue that exclusion of advanced dental service from this Medicare scheme would be inconsistent with the wider established principle that Medicare supports ‘all’ and not just ‘basic’ medical services.21

While it seems reasonable to question if all expenditure on indirect restorations is justified in terms of potential health outcomes, it is also clear that improving timely access to dental services offers significant health and cost benefits with regard to diabetes, vascular disease, infective endocarditis, aspiration pneumonia, and preventable hospitalisations.1–16 Also, it is common for those unable to afford private dental service to seek immediate relief from dental abscesses and cellulitis from antibiotics and analgesics prescribed by medical general practitioners. By subsidising attendance for these medical services, Medicare has long provided indirect dental support, and it is particularly unfortunate that antibiotic therapy alone is ineffective because only dental surgical intervention can remove the cause of dental infection (Figure 1). A less wasteful and more effective use of Medicare funds would be to support access to the necessary dental services, at least at the time of acute pain, but preferably before infection spreads to bone and soft tissues. We also have concern that the medical prescription of antibiotics unsupported by dental surgical intervention increases the community load of antibiotic-resistant organisms, hastening tread into the post-antibiotic era. Without access to more detailed Medicare data, it is not possible to properly evaluate the wider health and cost benefits of the CDDS, but further research in this area seems warranted.

Differences between states regarding the use of indirect restorations and bridges were marked in the current study, and may reflect differences in treatment needs and or cultures. Separately, in light of the longer clinical survival of amalgam as opposed to adhesive restorations,18,19 the proportionately much greater use of adhesive posterior restorations over amalgam suggests a clinically inappropriate imbalance between the use of these materials. Similarly, the data indicate only very limited use of oral hygiene instruction, which should ideally be an important component of any treatment plan for patients suffering significant dental disease.

An apparently excessive variation in treatment planning has been of concern for some time,33–36 although it is possible to reduce this with standardised training.37 The variability in treatment planning seen across state jurisdictions in the current study may reflect the lack of national standards for dental diagnosis and treatment planning, and we suggest that application of such standards to the CDDS would improve outcomes. Clear guidelines regarding the suitability or otherwise of crown and bridgework for given clinical settings would also likely greatly reduce the costs of the CDDS.

The average cost of CDDS services was significantly less than the maximum permitted per patient, so current arrangements appear sufficiently generous to fund services required. With progression of patients from acute through to maintenance service, the per-patient cost of CDDS is expected to reduce. Establishment of pre-approval for some services, together with inclusion in the CDDS of dental therapists and hygienists able to deliver more preventively orientated services at lower cost would help contain expense, were the program expanded to include the entire Australian population.

Competing interests

The second author is the chairman of the Association for the Promotion of Oral Health, which has advocated strongly for retention and improved regulation of the CDDS, as well as for expansion to eventually include the entire Australian population.

Ancillary