Note 10 - Segment and Geographic Data - Summary of Operations by Geographic Area (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Product sales, net	$ 2,700,902	$ 2,924,707
Dental Segment [Member]
Product sales, net	2,693,352	2,853,657
Medical Segment [Member]
Product sales, net	7,550	71,050
Domestic [Member]
Product sales, net	951,237	997,058
Domestic [Member] | Dental Segment [Member]
Product sales, net	943,687	988,908
Domestic [Member] | Medical Segment [Member]
Product sales, net	7,550	8,150
Rest of World [Member]
Product sales, net	1,389,701	1,421,249
Rest of World [Member] | Dental Segment [Member]
Product sales, net	1,389,701	1,358,349
Rest of World [Member] | Medical Segment [Member]
Product sales, net	0	62,900
CHINA
Product sales, net	359,964	506,400
CHINA | Dental Segment [Member]
Product sales, net	359,964	506,400
CHINA | Medical Segment [Member]
Product sales, net	0	0
Instruments [Member] | Domestic [Member]
Product sales, net	122,968	176,016
Instruments [Member] | Domestic [Member] | Dental Segment [Member]
Product sales, net	122,968	176,016
Instruments [Member] | Domestic [Member] | Medical Segment [Member]
Product sales, net	0	0
Instruments [Member] | Rest of World [Member]
Product sales, net	453,560	425,755
Instruments [Member] | Rest of World [Member] | Dental Segment [Member]
Product sales, net	453,560	383,255
Instruments [Member] | Rest of World [Member] | Medical Segment [Member]
Product sales, net	0	42,500
Instruments [Member] | CHINA
Product sales, net	0	150,000
Instruments [Member] | CHINA | Dental Segment [Member]
Product sales, net	0	150,000
Instruments [Member] | CHINA | Medical Segment [Member]
Product sales, net	0	0
Handpieces [Member] | Domestic [Member]
Product sales, net	803,409	803,134
Handpieces [Member] | Domestic [Member] | Dental Segment [Member]
Product sales, net	795,859	794,984
Handpieces [Member] | Domestic [Member] | Medical Segment [Member]
Product sales, net	7,550	8,150
Handpieces [Member] | Rest of World [Member]
Product sales, net	923,952	974,934
Handpieces [Member] | Rest of World [Member] | Dental Segment [Member]
Product sales, net	923,952	954,534
Handpieces [Member] | Rest of World [Member] | Medical Segment [Member]
Product sales, net	0	20,400
Handpieces [Member] | CHINA
Product sales, net	359,964	356,400
Handpieces [Member] | CHINA | Dental Segment [Member]
Product sales, net	359,964	356,400
Handpieces [Member] | CHINA | Medical Segment [Member]
Product sales, net	0	0
Accessories [Member] | Domestic [Member]
Product sales, net	24,860	17,908
Accessories [Member] | Domestic [Member] | Dental Segment [Member]
Product sales, net	24,860	17,908
Accessories [Member] | Domestic [Member] | Medical Segment [Member]
Product sales, net	0	0
Accessories [Member] | Rest of World [Member]
Product sales, net	12,189	20,560
Accessories [Member] | Rest of World [Member] | Dental Segment [Member]
Product sales, net	12,189	20,560
Accessories [Member] | Rest of World [Member] | Medical Segment [Member]
Product sales, net	0	0
Accessories [Member] | CHINA
Product sales, net	0	0
Accessories [Member] | CHINA | Dental Segment [Member]
Product sales, net	0	0
Accessories [Member] | CHINA | Medical Segment [Member]
Product sales, net	$ 0	$ 0