It is important to note that many of the international markets that we’re investing in are growing materially above the Company’s average rate. Overall, our investments in key markets around the world will enable us to compete more effectively today and in the years to come.
Let me reiterate the two key pillars of our successful strategy. To expand our outstanding portfolio of high-tech dental products through continuous innovation. We have invested over $250 million in the past six years in the pursuit of creating new and enhanced products and solutions to continue our world-class global sales and service infrastructure. We’re active in over 135 countries around the globe. We continue to execute on our strategy giving Sirona a clear competitive advantage and enabling us to deliver consistently strong organic.
I will now turn the call over to Simone, who will review our second quarter financials.
Simone BlankThank you, Jost. In the second quarter our revenues increased $17.1 million to $231.9 million, up 8% or up 11.1% on a constant currency basis. Our double-digit revenue growth was mainly driven by continued strong performance in international markets, which increased 9.2% or up 13.7% constant currency. Sales were particularly robust in the Asia Pacific region. In the United States revenues increased 4.9% compared in the first quarter of this fiscal year. Sirona’s operating income plus amortization increased 10.9% to $52.2 million. Moving on to a review of our business segment. Revenues in our CAD/CAM segments increased 11.1% to $85.6 million or up 13.7% on a constant currency basis. CAD/CAM revenues benefited from very strong growth in international market. We continue to get excellent feedback from the marketplace on our CEREC 4.0 software. Dentists appreciate the ease of use, the ability to design multiple restorations and the increased processing speed. In the second quarter we also successfully launched the inlab 4.0 software for all our customers. Our CAD/CAM segment margin was 70%, down 160 basis points compared to the prior-year period, but on the levels of the full fiscal year 2011. The decrease in the quarter was mainly driven by current promotion.