wp_registered_widgets doesn’t contains my widgets

Founded here:
wp-includes/class-wp-widget.php #248

public function _register() {
    $settings = $this->get_settings();
    $empty = true;

    // When $settings is an array-like object, get an intrinsic array for use with array_keys().
    if ( $settings instanceof ArrayObject || $settings instanceof ArrayIterator ) {
        $settings = $settings->getArrayCopy();
    }

    if ( is_array( $settings ) ) {
        foreach ( array_keys( $settings ) as $number ) {
            if ( is_numeric( $number ) ) {
                $this->_set( $number );
                $this->_register_one( $number );
                $empty = false;
            }
        }
    }

    if ( $empty ) {
        // If there are none, we register the widget's existence with a generic template.
        $this->_set( 1 );
        $this->_register_one();
    }
}

The get_settings function retrieve the options for the widget saved in the wp_options table. I’ve in someway lost these informations into the database.