Decision #91/21 - Type: Workers Compensation


The worker is appealing the decision made by the Workers Compensation Board ("WCB") that they are not entitled to coverage for the proposed dental treatment. A videoconference hearing was held on July 13, 2021 to consider the worker's appeal.


Whether or not the worker is entitled to coverage for the proposed dental treatment.


The worker is entitled to coverage for the proposed dental treatment.


The worker was diagnosed with mesothelioma on November 23, 2012 and filed a Worker Incident Report with the WCB on December 6, 2012 reporting exposure to asbestos during their employment that resulted in that diagnosis. The WCB investigated and on January 10, 2013, accepted the worker’s claim for occupational exposure to asbestos.

The worker was treated with a series of six cycles of chemotherapy between February 2013 and June 2013. On July 26, 2013, the worker’s spouse contacted the WCB to advise the worker required dental treatment as some of their teeth had cracked and fallen out, which their treating dentist attributed to the recent chemotherapy.

On October 7, 2013, the WCB received a report from the worker’s treating dentist. The dentist advised the worker had been a long-term patient and during the time period the worker was undergoing chemotherapy, endured a great deal of discomfort due to lesions in their mouth. The dentist noted that proper maintenance of the worker’s teeth was difficult due to those lesions and resulted in tooth fractures. The treating dentist also provided a treatment plan for the worker’s dental work for the WCB to review.

On the same date, the worker’s WCB case manager requested a WCB dental consultant review the worker’s file. The WCB dental consultant requested further information from the worker’s dentist in the form of imaging records pre-dating the worker’s diagnosis. When the records were received, the worker’s WCB case manager again requested a review of the worker’s file by the WCB dental consultant. On November 12, 2013, the WCB advised the worker’s treating dentist responsibility for the proposed dental treatment was accepted.

Further dental treatment was proposed by the worker’s treating dentist on May 12, 2014 and June 4, 2014. The proposed treatment was reviewed by a WCB medical advisor on June 25, 2014 who concluded “…I am unable to establish a probable relationship between [the worker’s] dental conditions and systemic chemotherapies received.” A WCB dental consultant and the WCB’s Senior Medical Advisor reviewed the proposed treatment June 30, 2014. The Senior Medical Advisor provided an opinion that “The onset of dental fractures sometime prior to the first report to WCB on May 21, 2013 is not medically accounted for in relation to lessened oral health maintenance for the previous 3 months.” Further, the Advisor stated the WCB dental consultant reviewed the worker’s file and opined the “…dental issues as described in a September 30, 2013 report from the treating dentist have not been medically accounted for in relation to chemotherapy dating to early February 2013.” However, the Medical Advisor noted that as financial responsibility was accepted for the dental work on the worker’s teeth number 24 and 25, the WCB would continue to accept responsibility for the proposed treatment on those teeth but not for the additional proposed treatment on the worker’s other teeth.

On September 19, 2014, after further discussion with the worker’s treating dentist, the WCB dental consultant also approved the proposed treatment to the worker’s tooth number 23.

The worker’s treating dentist provided the WCB with additional proposed dental treatment on April 28, 2015 involving the worker’s tooth number 22. The WCB dental consultant reviewed the proposed treatment and on April 28, 2015, opined the requested treatment for tooth number 22 should not be approved. On May 27, 2015, the WCB advised the worker that it did not accept responsibility for the dental treatment to tooth number 22.

The worker requested reconsideration of the WCB’s decision to Review Office and on September 3, 2015, Review Office determined responsibility for the proposed dental treatment for tooth number 22 should be accepted.

The worker continued to attend for regular dental visits and on April 15, 2019, the treating dentist submitted a further proposed dental treatment, noting the treatment was required due to the worker’s systemic chemotherapy treatment. The WCB’s dental consultant reviewed the proposed treatment plan and imaging on April 17, 2019 and concluded the proposed treatment was not related to the worker’s compensable injury but could be accounted for “…in relation to the natural history of the worker’s pre-existing dental health…”. On April 23, 2019, the WCB advised the worker and the treating dentist that it would not accept responsibility for the proposed dental treatment.

On May 6, 2019, the worker requested reconsideration of the WCB’s decision to Review Office. In their submission, the worker noted they saw their treating dentist on a regular basis during the time they were having the chemotherapy treatment and the dentist noted damage to their teeth and related it to that treatment. Review Office determined on June 12, 2019 that the worker was not entitled to coverage for the proposed dental treatments, relying upon the opinion of the WCB dental consultant that the proposed treatment was as a result of the natural history of the worker’s pre-existing dental health and could not establish a causal relationship between the chemotherapy treatment the worker underwent seven years previously. The worker’s treating dentist provided a further letter and supporting medical article in support of the worker’s appeal on September 17, 2019. On September 18, 2019, Review Office advised there would be no change to the earlier decision.

The worker filed an appeal with the Appeal Commission on March 5, 2021. A videoconference hearing was arranged for July 13, 2021.


Applicable Legislation and Policy

As the worker was employed by a federal government agency or department, their claim is adjudicated under the Government Employees Compensation Act (the "GECA"). Section 4(1) of the GECA provides that an employee who is caused personal injury by an accident arising out of and in the course of their employment is entitled to compensation.

"Accident" is defined in s 2 of the GECA to include "a wilful and an intentional act, not being the act of the employee, and a fortuitous event occasioned by a physical or natural cause." Section 4(2)(a) of the GECA provides that a federal government employee in Manitoba is to receive compensation at the same rate and under the same conditions as a worker who is covered under The Workers Compensation Act (the "Act").

The Appeal Commission and its panels are bound by the provisions of The Workers Compensation Act, regulations under that Act and the policies established by the WCB's Board of Directors.

The Act sets out the definition of an accident in s 1(1) as follows:

"accident" means a chance event occasioned by a physical or natural cause; and includes 

(a) a wilful and intentional act that is not the act of the worker, 

(b) any 

(i) event arising out of, and in the course of, employment, or 

(ii) thing that is done and the doing of which arises out of, and in the course of, employment, and 

(c) an occupational disease, 

and as a result of which a worker is injured….

When it is established that a worker has been injured as a result of an accident at work, a worker is entitled to benefits under s 4(1) of the Act. When the WCB determines that a worker requires medical aid as a result of an accident, compensation is payable under s 37 of the Act. Medical aid is provided for under s 27 of the Act which states that the WCB may provide a worker with such medical aid as the board considers necessary to cure and provide relief from an injury resulting from an accident.

The WCB has established Policy 44.120.10, Medical Aid (the “Medical Aid Policy”) which defines key terms and sets out general principles regarding a worker's entitlement to medical aid. This Policy confirms that medical aid includes dental treatment. The general principles that apply include the following:

• The Board is responsible for the supervision and control of medical aid funded under the Act or this policy. 

• The Board determines the appropriateness and necessity of medical aid provided to injured workers in respect of the compensable injury. 

• In determining the appropriateness and necessity of medical aid, the Board considers: 

o Recommendations from recognized healthcare providers; 

o Current scientific evidence about the effectiveness and safety of prescribed/recommended healthcare goods and services; 

o Standards developed by the WCB Healthcare Department. 


• The Board's objectives in funding medical aid are to promote a safe and early recovery and return to work, enable activities of daily living, and eliminate or minimize the impacts of a worker's injuries.

The WCB has also established Policy, Further Injuries Subsequent to a Compensable Injury (the “Further Injuries Policy”). This Policy sets out that a further injury occurring subsequent to a compensable injury is compensable: (i) when the cause of the further injury is predominantly attributable to the compensable injury; or (ii) when the further injury arises out of a situation over which the WCB exercises direct specific control; or (iii) when the further injury arises out of the delivery of treatment for the original compensable injury. The Administrative Guidelines to this Policy clarify that:

A subsequent accident or injury may be compensable if a relationship between the original compensable injury and the subsequent injury is established where: 

1. The original injury causes or significantly contributes to the subsequent injury.... 

2. The subsequent injury arises out of a situation over which the WCB exercises direct control.... 

3. The subsequent injury arises out of the delivery of treatment for the original injury (unless the treatment is not acceptable to the WCB) .... The WCB will not accept responsibility for a subsequent non-compensable injury where there is no causal relationship between the subsequent and the original injury....

Worker’s Position

The worker appeared in the hearing with their spouse as a support and was represented by their son, who provided an oral submission on behalf of the worker. The worker provided testimony through answers to questions posed by the panel members.

The worker’s position, as outlined by their representative, is that the dental work now required as outlined in the dental plan of April 10, 2019, is a result of and arose out of the chemotherapy treatment required for the worker’s compensable diagnosis of mesothelioma.

In answer to the Review Office decision of June 12, 2019, the worker’s representative noted the decision was based upon concerns regarding time lapse between chemotherapy treatment and the date of the request for dental care, as well as a lack of evidence of a causal link between chemotherapy and dental issues. The worker’s representative pointed to numerous reports in the worker’s file indicating the worker experienced ongoing dental issues, including jaw pain, tooth breakage and intra-oral lesions through the period of chemotherapy and noted that the lack of research on the effect of chemotherapy on oral health does not mean there are no such effects. The worker’s representative noted that although the WCB had previously stated that the lack of research means there is no evidence of a causal link between chemotherapy and oral health, the WCB has nonetheless also accepted the worker’s prior claims for dental repair as arising out of chemotherapy required to treat the compensable diagnosis of mesothelioma. Further, the worker’s representative pointed out the comments of the treating oncologist as to the growing evidence of a potential relationship between chemotherapy and microbial changes in the body that may also impact dental health.

The worker’s representative argued that a break in time, or lack of continuity of dental problems after the chemotherapy ended is not evidence of an absence of causality, and that there is no evidence supporting the WCB’s position that the dental impacts near in time to the chemotherapy are causally related to the chemotherapy but that the more recent dental issues are not related. If it is probable that any of the damage to any of the worker’s teeth is related to the chemotherapy, then it is also probable that all damage to the worker’s teeth is related, unless there is evidence of another cause.

Here there is no evidence of another cause for the damage. The worker’s representative stated there is no evidence the worker had pre-existing poor oral health, noting the worker’s dentist has confirmed the worker had no major dental issues prior to 2013. The worker confirmed to the panel that they continued with regular preventative dental care in the period since their chemotherapy concluded as well as addressing acute dental issues as required. The worker also described that tooth 13 broke while they were eating a breakfast of oatmeal, and they nearly swallowed the tooth in the process.

In sum, the worker’s position is that there is no evidence of any other cause for the dental issues identified in the treatment plan of April 10, 2019. Further, on the basis of opinions of the treating dentist and oncologist, as well as the WCB’s prior and continuing acceptance of a causal relationship between the worker’s chemotherapy and his dental concerns with teeth 22-25, the WCB should also accept responsibility for the treatment plan of April 10, 2019 as being related to and arising out of the compensable diagnosis.

Employer’s Position

The employer did not participate in the appeal.


The appeal arises in respect of a request for dental treatment that the worker believes is related to and caused by the treatment received for the compensable diagnosis of mesothelioma. For the worker’s appeal to succeed, the panel would have to determine that the medical aid (dental treatment) requested is required to cure and provide relief from the compensable injury or arises out of the delivery of treatment for that injury. The panel was able to make such findings for the reasons outlined below.

The panel reviewed and considered the file history with respect to the worker’s dental issues, noting that chart notes from the worker’s cancer treatment program indicate the worker had numerous dental issues arise in April 2013 and that in May 2013 the worker’s dentist advised that they would not address the dental concerns until after chemotherapy concluded. The treating dentist reported on September 30, 2013 that the worker had been a patient since 1965, seen regularly and noted the worker:

“...had no major problems orally until chemotherapy was instituted. During that period [they] endured a great deal of discomfort especially in [their] mandible and maxilla. As a result [they were] unable to masticate [their] food properly due to this pain, as well as from the oral lesions in [their] mouth. Consequently proper maintenance of [the worker’s] oral health was very difficult resulting in carious lesions and dental fractures.”

In a June 25, 2014 file memorandum, a WCB dental advisor reviewed the evidence with respect to the impact of cancer therapies on teeth and gums and noted that a systematic review from 2010 found there to be a lack of clinical trials to evaluate the extent of dental disease associated with cancer therapy. On this basis, the dental advisor indicated they were “unable to establish a probable relationship between [the worker’s] dental conditions and systemic chemotherapies received.” Nonetheless, on September 22, 2014 another WCB dental advisor approved treatment for the worker’s tooth 23 arising out of the compensable injury, stating they would recommend this funding “but would not recommend accepting financial responsible (sic) for treatment directed at any additional teeth.”

On May 8, 2015, this dental advisor stated in a claim note with reference to the September 22, 2014 approval, that “Based on our conversation, understanding and agreement, it is my opinion that the requested dental treatment for tooth number 22 should not be approved for compensation.” The panel noted that there was no reference in this further opinion of the WCB dental advisor to the question of a causation, but only to the prior agreement with the worker’s dentist.

On August 31, 2015, the WCB dental consultant conducted a review of the worker’s entire WCB file and provided the following opinion:

“Prior to the worker’s chemotherapy treatment in May 2013, it was noted in the patient’s dental chart that [the worker] had poor oral hygiene. There was moderate plaque and calculus on [their] teeth with moderate hemorrhaging. There was also heavy food debris on [their] teeth and [their] gingival tissue were sensitive. It was noted that [the worker] does not floss. With this new information provided, on the balance of probabilities, it is possible the chemotherapy treatment with [the worker’s] oral environment could have accelerated the fracturing of teeth 23, 24 and 25.”

Similarly, Review Office found, in considering the worker’s request for dental treatment of tooth 22 that:

“We acknowledge that there was poor oral hygiene prior to the chemotherapy but the chart notes did not indicate the need for major dental work. The Review Office accepts and places weight on the dental advisor’s opinion that chemotherapy, along with the worker’s current oral health, could have caused further dental deterioration. The Review Officer determines that there is coverage for dental treatment for tooth 22. We find that, on a balance of probabilities, there is a relationship between the need for the dental treatment and the effects of the compensable injury (need for chemotherapy).”

The worker’s treating oncologist, in a progress note dated July 5, 2019, wrote that:

“...I am not aware of any direct link between administration of systemic chemotherapy and impact on dental health; however, there could be an impact in terms of micro-flora in the oral cavity, inflammation, etc which might be a contributing factor. Certainly there is an impact of radiotherapy on dental health which has been demonstrated because of its affect on salivary production.”

The oncologist wrote to the WCB on September 17, 2019 in support of the worker’s request for medical aid for dental treatment, providing a research paper that outlined the findings of a study of dental health of breast cancer patients who received chemotherapy. The oncologist noted:

“Speculation in the paper is that chemotherapy alters hormonal balance leading to xerostomia; also, that chemotherapy may alter microbial flora in the oral cavity and effects on the immune system. I would expect that these same effects of chemotherapy would affect patients treated for other malignancies and not be limited only to breast cancer patients.”

Noting that further clinical studies are required to verify the paper’s findings, the oncologist went on to comment on the worker’s case, stating:

“...the aging process usually has a significant effect on dental health which relates to cumulative trauma, gum disease and likely an element of reduced salivary production as an individual ages. [The worker] is one of the few long-term survivors of mesothelioma. [Their] gratifying length of survival and advancing age mean [the worker] is more at risk of dental disease and deterioration. I would have to conclude that the impact of systemic therapy, as described above, may also be relevant to [the worker’s] current dental condition.”

The worker testified to having ongoing issues of dry mouth, and that their treating dentist in 2018 prescribed a topical gel treatment for this issue, but that the treatment has not been effective.

The treating dentist noted, in a letter to the WCB dated February 16, 2021 that there can be many long-term effects of chemotherapy including dental problems. The dentist goes on to comment that “Limiting coverage to specific tooth numbers in this case does not seem reasonable considering the amount of Chemotherapy [the worker] endured, increasing the potential for future issues.”

On the basis of the evidence before the panel, we accept the worker’s position that it is possible, that if the chemotherapy treatment the worker received caused damage to some of the worker’s teeth, as previously determined by the WCB, it could also have caused damage to other teeth, including specifically those impacted in 2019.

While there is some evidence of poor oral hygiene immediately prior to the worker’s compensable diagnosis in 2012, there is no evidence of any significant pre-existing dental condition. This was confirmed by the worker’s long-term treating dentist in the letter of September 30, 2013.

With respect to the dental treatment requested on April 10, 2019, Review Office found it could not account for the lapse of “seven years” between the worker’s chemotherapy treatment and further dental damage and found there was no continuity to the chemotherapy given the absence of “more continuous problems with the worker’s teeth in the years post-treatment”. Review Office also noted that this gap between the end of chemotherapy treatment and the request for further dental treatment negated a causal relationship between the treatment and the dental issues. But the panel noted the worker’s testimony that after the chemotherapy treatment, which concluded in June 2013, less than 6 years prior to the relevant treatment request, the worker experienced numerous dental and oral cavity issues, including lesions, dry mouth and fragile teeth. During this period, the worker continued to receive treatment arising out of damage that the WCB accepted as being related to and arising out of treatment for the worker’s compensable injury. And when the worker’s long-term dentist retired in 2018, the worker sought ongoing treatment from a new dentist who trialed a new treatment for the worker’s continuing dry mouth symptoms. The evidence does not support the Review Office findings as to a lack of continuity of dental concerns.

The panel also does not find the gap in time between requests for dental treatment from 2015 to 2019 to be a barrier to the worker seeking further medical aid benefits as arising out of the compensable injury. As noted above, the file record reveals, in fact, that the worker has continued to require dental treatment throughout this period and even since then, with the WCB accepting responsibility for further treatment to teeth 22 and 23 as recently as March 2021.

Further, there is no evidence before the panel to suggest that there is any limitation in terms of when the possible effects of chemotherapy on dental health may become evident. As noted, by the WCB dental advisor and by the treating oncologist, there is a lack of clinical study on these effects. The worker is described by the oncologist as “one of the few” long-term survivors of mesothelioma, suggesting as well that it might be challenging for researchers to conduct any long-term longitudinal clinical studies of this group.

Review Office also accepted the April 17, 2019 opinion of the WCB dental advisor, upon a further file review that “...the recommended dental treatment dated April 10, 2019 is not in relation to the Compensable Injury, but can be dentally accounted for in relation to the natural history of the worker’s pre-existing dental health rather than to the workplace accident.” The panel notes there was no specific evidence provided by the dental advisor as a rationale to support this opinion. The panel does note that the worker was 79 years of age in April 2019 when the request for treatment at issue was made and that the dental chart notes from 2012, prior to the worker’s diagnosis, revealed some concern with respect to the worker’s overall dental health, but that the worker’s treating dentist indicated there were no significant concerns.

We accept the February 25, 2021 opinion of the treating oncologist that the worker’s dental concerns are likely compounded by age and time, and by the worker’s overall dental health. In other words, causation is likely multifactorial, but on the basis of the totality of evidence, the panel accepts that but for the chemotherapy treatment for the compensable injury, which the WCB has previously accepted as the cause of damage to the worker’s other teeth, the worker would likely not require this dental work at this time.

For these reasons, the panel finds, on the standard of a balance of probabilities, that the worker is entitled to coverage for the proposed dental treatment. The worker’s appeal is therefore granted.

Panel Members

K. Dyck, Presiding Officer
J. Witiuk, Commissioner
M. Kernaghan, Commissioner

Recording Secretary, J. Lee

K. Dyck - Presiding Officer
(on behalf of the panel)

Signed at Winnipeg this 16th day of July, 2021