Offenbacher 2006.

Methods	Study design: RCT (pilot) Location: USA Setting: 2 antenatal clinics (1 high risk) in Raleigh, NC, USA Recruitment period: January 2001 to November 2003
Participants	Inclusion criteria: initially pregnant women with a history of a previous preterm/low birth weight birth, but this was subsequently dropped due to very low eligibility rates. Pregnant women < 22 weeks gestation ≥ 18 years of age at time of scaling and root planing or supragingival polish, 2 or more sites measuring ≥ 5 mm probing depths plus periodontal attachment loss of 1 to 2 mm at 1 or more sites with probing depths ≥ 5 mm; ≥ 20 teeth Exclusion criteria: multiple births, a positive history of HIV, AIDS, diabetes (gestational diabetes was acceptable), any medical contraindication to periodontal probing (e.g. congenital heart disease), and use of phentermine and fenfluramine (phen‐fen) for weight loss; currently undergoing periodontal treatment, chronic regimen of aspirin or non‐steroidal anti‐inflammatory drugs, chronic use of medications that cause gingival enlargement such as phenytoin, cyclosporin‐A, or calcium channel antagonists, 5 or more teeth requiring extraction, rampant decay or any other oral condition that, in the clinician's judgement, would place the woman at unacceptable risk if treatment was delayed, prescribed or using chlorhexidine or other mouthrinses with known antiplaque or anti‐inflammatory effects Mean age (± standard deviation (years)): Group A = 26.8 ± 5.5, Group B = 25.7 ± 5.4 (P = not significant) Gestational age: < 22 weeks History of preterm delivery: Group A = 75, Group B = 88.2 (P = not stated) Number randomised: n = 109 Number evaluated: n = 67 (74 completed baseline examinations)
Interventions	A) Antenatal periodontal treatment ‐ Scaling and root planing and polishing + oral health instructions and a sonic power toothbrush and instructions for use (n = 56 (40)) B) Antenatal periodontal treatment ‐ Supragingival debridement + manual toothbrush with no instruction (n = 53 (34)): postnatal scaling and root planing therapy was provided ˜ 6 weeks postpartum with sonic toothbrushes and instruction in their use All participants were interviewed by the dental hygienist, however, it is not clear whether they also administered intervention
Outcomes	Preterm birth; gingival index (0 = normal gingiva; 1 = mild inflammation; 2 = moderate inflammation; 3 = severe inflammation); plaque index (0 = absence of plaque on clinical crown; 3 = soft deposits covering more than 2‐thirds of the crown); probing depth (6 sites per tooth on all teeth present in the mouth); recession (6 sites per tooth on all teeth present in the mouth or isolated teeth); bleeding on probing (for each quadrant ‐ 0 = absence of bleeding; 1 = bleeding present)
Funding	Study was principally supported by Philips Oral Healthcare
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "109 subjects were randomised" Comment: insufficient information
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not feasible
Blinding of obstetric outcome assessment (detection bias)	Unclear risk	Study was referred to as "examiner‐blinded". No further details stated
Incomplete outcome data (attrition bias) All outcomes	High risk	High attrition rate: 16 of the 56 women (29%) assigned to the intervention group and 19 of the 53 women assigned to the control group (36%) did not complete baseline periodontal examinations (due to moving or dropping out of the study). This includes 2 fetal deaths (not reported which group(s) these were from). A further 5 women in the intervention group and 2 in the control group did not have birth outcome data, leaving 35 women in the intervention group and 32 in the control group. Postpartum periodontal examinations were collected from 25 intervention and 28 control mothers
Selective reporting (reporting bias)	Low risk	Expected outcome reported
Other bias	High risk	"Randomization did not balance the primary exposure" of periodontal status