Cameron Naismith Smith hit his victim because he had shown an interest in his then-girlfriend, the Magistrate’s Court heard.
Crown Advocate Lauren Taylor, prosecuting, said the victim still needed to receive dental treatment, and urged the court to delay imposing a compensation order until the true cost of the work was known.
Assistant Magistrate Peter Harris ordered Smith to pay an initial sum of £1,420 towards the treatment, and warned that a further compensation order would follow.
The judge added: “This was an unprovoked assault. It has caused permanent injury.
“Hopefully it can be remedied, but the impact will certainly be quite long lasting.”
Smith pleaded guilty to grave and criminal assault and was ordered to complete 130 hours of community service and a 12-month probation order.