Within the limits of this case-controlled study, it can be concluded that lateral ridge augmentation procedures in atrophic alveolar ridges using bioresorbable matrix barriers without achieving primary flap closure or in the case of early exposures can still lead to clinically satisfying ridge width gain that allows for the placement of dental implants. However, exposures seem to limit the ridge width gain. Therefore, in esthetic challenging situations, efforts should be made to achieve primary wound closure and to avoid subsequent membrane exposure.