Table 1 Summary of the included studies with main results

Yuen et al. 2009, USA [18]

253 (T1DM and T2DM); ≥18y/

20-Q; V

K

▪ OH~DM: 47%

▪ Adequate OH knowledge significantly associated with brushing (twice/day), flossing (once/day), and dental visit (twice/year) (P < 0.01)

▪ Receiving OH information significantly associated with adequate OH knowledge (P = 0.008)

b

P

▪ Brushing: 61.2%

▪ Flossing: 34.9%; never: 35.3%

▪ Dental visit: 58.6%

Tomar et al. 2000, USA [25]

N = 4570 (DM), 101,148 (NDM); ≥25 y/

4-Q; V

A

▪ Reasons behind not visiting dentists: perceived need to visit a dentist (37.2%), cost (28.6%), fear/anxiety (10.5%), and other reasons (23.7%)

a

P

▪ Dental visit: PWD 65.8% vs NDM 73.1% (P = 0.0000); result was consistent even after controlling confounders and other correlates: sex, age, race or ethnicity, educational attainment, income, and dental insurance coverage (OR 0.82, 95% CI 0.73–0.93)

Macek et al.,2008, USA [26]

N = 725 (DM), 7816 (NDM); ≥25 y

P

▪ Dental visit: 56.8% PWD vs 64.7% NDM; result remain consistent even after adjusting periodontitis status, age, sex, race/ethnicity, education, poverty status and dental insurance status

a

Moffet. 2010, USA [27]

N = 12,405 (DM)

Q: V

P

▪ Dental visit: 77% of patients (82% with dental insurance vs 61% without dental insurance (age sex adjusted OR 2.66, 95%CI 2.33–3.0).

a

Oh et al. 2012, USA [28]

N = 1209 (DM) 9140 (NDM); ≥45 y

P

▪ Dental visit: 72.7% PWD vs 83.5% NDM (95% CI: 82.6%–84.4%, p < .0001)

▪ Diabetes status adversely affected the rate of preventive dental care

▪ Adults from racial/ethnic minority background (OR = 0.51, 95% CI: 0.33–0.79) or lower educational attainment (OR = 0.64, 95% CI: 0.47–0.88) had lower odds of having received preventive dental care

a

Orlando, et al., 2010, USA [29]

N = 89 (T1DM);

12–19 y/

40-Q

K

▪ Perio~DM; 44%

▪ Health care providers advised PWD for dental check up (77%)

b

A

▪ Care of their OH was as important as taking care of medical health: 49%

▪ Plaque or tartar build up was a problem: 33%

P

▪ Dental visit: 95.4%; majority (86.5%) paid through insurance

Moore et al. 2000, USA [30]

N = 390 (T1DM), 203 age matched (NDM)

K

▪ OH would be better if not have diabetes: 18.2%

▪ Health care providers advised for oral hygiene and dental visit: 27.1%

b

A

▪ PWD rated their overall oral health lower than control subjects

▪ The cost of dental care was main reason for avoiding routine visit

P

▪ Brushing: 72.2% PWD vs 80.2% NDM

▪ Flossing: 33% vs 30%

▪ Dental visit: 68.9% vs 75.7%

Alves et al., 2009, Brazil [31]

N = 55 (T1DM), 55 age matched (NDM)

K

▪ None enrolled in an oral health educational program

▪ Informed to visit dentist by health professional: 65.5%

b

A

▪ Reasons for avoiding dental visit: difficulty in scheduling an appointment (36.1%) and high treatment costs (27.8%)

P

▪ Brushing: 92.7% PWD vs 76.4% NDM

▪ Flossing: 30.9% vs 18.2%

▪ Dental visit: 63.8% vs. 48.7%

Arunkumar et al. 2015. India [32]

N = 185 (T2DM)

K

▪ Perio~DM: 33%

▪ Informed about OH from physicians; none

b

Kejriwal et al.2014, India [33]

N = 300 (T2DM);18-65y/

20-Q; V

K

▪ Increased risk for oral diseases: 50%

▪ Informed about OH from physicians: 10%

b

A

▪ Preferred to see physicians for oral problem: 41%

P

▪ Brushing: 65%

▪ Dental visit (in 6 months): 27%

Sandberg, et al.2001, Sweden [34]

N = 102 (T2DM), 102 age, gender matched (NDM); 34-77y

K

▪ OH~DM: 27%

A

▪ Perceived satisfaction with teeth and mouth: satisfied (83.3%), dissatisfied (16.7%)

▪ Main reason for avoiding dental visits: belief that it was not necessary

b

P

▪ Brushing: ≥ 1times: 91.3%

▪ Dental visit: 85.1% PWD vs 95.1% NDM (P < 0.05)

Lee et al. 2009, South Korea [35]

N = 75 (T2DM)

A

▪ 62.7% perceived their OH status as poor with 37.3% perceived as good

b

P

▪ Brushing: 90.6%

▪ Dental visit (within 6 months): 45.3%

Sahril et al. 2014, Malaysia [36]

N = 4017 (T2DM);

≥18 y

K

▪ OH~DM: 35.5%

b

A

▪ Wanted dental referral: 59.9%

▪ Reasons not wanting a referral: perceived lack of necessity, absence of dental problems and perception that dental problems were not serious

P

▪ Dental visit: 16.7%; highest among: 18–19 y, lowest: ≥70 yrs

Aggarwal et al. 2012, India [37]

N = 500 (T2DM); ≥35 y/

K

▪ OH~DM: 38.4%

▪ Never received a referral for dental care: 79.4%

b

A

▪ Avoiding dental visits due to unpleasant experience: 18.4%

P

▪ Brushing: 33.4%

▪ Dental visit: 75.6%; visited for regular dental checkups: 10.8%

Al Habashneh et al. 2010, Jordon [38]

N = 405 (DM); RR 81%

33-Q

K

▪ Perio~DM: 47.7%; source of information: diabetes nurse (43%), physicians (38%), dentist (30%),

b

A

▪ Did not pay attention to bleeding gums: 13.7%

▪ Rated their overall oral health as poor: 60%

P

▪ Brushing: 28.1%

▪ Dental visit (regular): 10%

Allen et al., 2008, Ireland [39]

N = 101 (DM)

31-79y/

20-Q; V

K

▪ Perio~DM: 33%; source of information: dentist (51%), diabetes care providers (32%)

b

A

▪ Would choose to save a painful posterior tooth: 32%

P

▪ Dental visit: 42.5%; not attended for > 5 yrs.: 34%

Badiah et al. 2012. Malaysia [40]

N = 102 (DM)

RR 93%/

10-Q; V

K

▪ Perio~DM: 26.5%

▪ Needs to be extra careful on oral health practices: 19.6%

▪ Those who were aware of the risk and the need for extra oral health practice were more among those who brushed at least twice a day and regular attendees

b

P

▪ Brushing: 80.4%

▪ Dental visit (1-2y): 33.3%

Bahammam .2015, Saudi Arabia [41]

N = 454 (T1DM & T2DM); RR-87%.

K

▪ Perio~DM: 46.7%

▪ Gum disease makes it harder to control diabetes: 21.8%

▪ Participants who had regular dental visits had significantly greater awareness of the Perio~DM link (P < 0.05)

b

P

▪ Brushing: 26.8%,

▪ Flossing: occasional: 23.2%; never:73.6%

▪ Dental visit: 12.6%

Bowyer et al. 2011, UK [42]

N = 229 (T1DM & T2DM); ≥ 25 y;

RR 37.2%

K

▪ Aware of mouth dryness: 43%

▪ Never received any OH advice: 69.1%

b

A

▪ Reasons for avoiding dental visit: cost (43.9%), lack of need (37.6%) and unpleasant visit (19.1%)

P

▪ Brushing: 67.2%

▪ Flossing: 15.3%

▪ Dental visit: 85.2%

Kamath,net al.2015, India [43]

N = 137 DM

RR 90.6%

K

▪ Perio~DM: 22.5%

c

P

▪ Brushing: 33.3%

▪ Dental visit: 27.5%

Mirza et al. 2007, Pakistan [44]

N = 240 (T1DM & T2DM)/

Q;V

K

▪ Aware about OH complications: 35.4%

▪ OH Knowledge was significantly related to brushing frequency (p = 0.005) as counselled patients brushed more frequently than uncounselled (53.4% vs 22.3%)

b

A

▪ Denied of DM~OH: 7.6%

▪ If advised about their predisposition to oral disease, willing to increase brushing frequency (45%) and consult a dentist (23%). Nevertheless, some (31.5%) were not reluctant to change

P

▪ Brushing: 24%

Sadeghi et al. 2014, Iran [45]

N = 200 (DM)

Q; V

K

▪ OH~DM: 36.5%; source of information: dentist (65%), physicians (35%)

b

P

▪ Brushing: 7%; no brushing: 49.5%

▪ Dental visits: 83%

Al Amassi et al.2017, Saudi Arabia [46]

N = 278 (DM); 18 -64y/

20-Q

K

▪ Perio~DM: 75.9%; source of information: media (31%), dentist (23%), physicians (21%)

▪ Controlling diabetes is important to minimize OH complications: 74.4%

▪ Patients with higher levels of education had greater awareness of the increased risk of OH problems and had better oral hygiene practices than those with lower levels of education (p < 0.05)

c

P

▪ Brushing: 19.1%

▪ Regular dental visit: 15.1%

Bangash et al. 2011, Pakistan [47]

300 (T1DM & T2DM)/

Q;V

K

▪ DM~OH: 64%; source of information: physicians (35%) and dentists (65%)

b

A

▪ Denied existence of a link OH~DM: 23%

▪ Would increase brushing frequency if told of their predisposition to oral disease: 30%

P

▪ Brushing: 86%

Ummadisetty et al. 2016, India [48]

N = 60 (DM),143 (NDM); 40-55y/

Q;V

K

▪ Perio~DM: 61.7%; source of information: physicians (36.6%) and dentist (30.69%)

▪ Physicians advised to visit a dentist: 46%

Eldarrat. 2011, UAE [49]

N = 100 (DM)

RR 50%

K

▪ Perio~DM: 60%

b

A

▪ Main reason of dental visit: due to pain/discomfort

P

▪ Brushing: 31%; did not brush daily: 19%

▪ Flossing: once a day: 11%; never: 66%

▪ Dental visit: 40%

Karikosk et al. 2002, Finland [50]

N = 336 (T2DM); 1 ≥ 18 y/

29-Q

A

▪ Main reason for not seeing a dentist: not having any problems (95%)

▪ Important for the diabetes nurse to also offer advice about dental care: 92%

b

P

▪ Brushing: 38%

▪ Dental visit: 63%

Kanjirath,P.P, 2011, USA [52]

N = 77 (DM) and 366 (NDM)

P

▪ Brushing: 31.5% PWD vs 49% NDM

▪ Flossing: 19.4% vs 26.7.%

▪ Dental visit: 86.7% vs 82.2%

b