Table 2.

Assessment of risk of bias and heterogeneity within and across the included studies

Category	Ivanovski et al. [ 34 ]	Donos et al. 2011 [ 35 ]	Bryington et al. [ 36 ]	Thalji et al. [ 37 ]
Study design
Comparison	None (only SLActive)	SLA vs. SLActive	TiOBlast vs. Osseospeed	TiOBlast vs. Osseospeed
Setting	University	University	University	University
Population, inclusion criteria	9 healthy volunteers with no mandibular third molars, no contraindications for oral surgery; age 21 to 48, median 29 years	9 healthy volunteers with no mandibular third molars; age 21 to 48, median 29 years	6 women, 4 men; implant patients, systemically healthy (no HTN, diabetes, CVD); age 25 to 58, mean 36.2 years	9 women, 2 men; implant patients, systemically healthy; age 47 to 69, mean 60.2 years
Exclusion criteria	Smokers	Smokers	Smokers, pregnancy, periodontal/periapical disease, subjects taking bisphosphonates, hormone replacement therapy, corticosteroids	Smokers, uncontrolled diabetes, history of head/neck radiotherapy, taking corticosteroids, bisphosphonates
Comparability of groups	Unclear	Unclear	Unclear	Unclear
Potential confounders, e.g., post-op medication	Unclear	Unclear	Unclear	Unclear
Power calculation	No	No	No	No
Statistical correction	For multiple sampling	For multiple sampling	Unclear	For multiple sampling
Methods
Tissue analyzed	Peri-implant tissue	Peri-implant tissue	Implant-adherent cells	Implant-adherent cells
Genetic material analyzed	Total RNA	Total RNA	Total RNA	Total RNA
Success rate	Unclear	16/18 samples (88.8%)	7/10 subject samples (70%)	Unclear
Genotyping method	Microarray	Microarray	RT-PCR	Whole-genome microarray
Genotype counts	Yes	Yes	Yes	Yes
Blinding	Unclear	Unclear	Yes	Unclear
Reproducibility, validated genotyping accuracy	No	No	No	No

All studies were judged to be at a high risk of bias with substantial heterogeneity across studies.