Prospective observational study to determine optimal time to achieve osseointegration after dental implant installation in irradiated jaw bones in head neck cancer patients

After-surgery of head and neck cancers, patients have missing teeth that often leads in problems of eating, speech and compromised esthetics. Dental implants are titanium screws like fixtures which supports artificial teeth and useful to restore and rehabilitate the missing teeth and surrounding structure.

However, many of the head and neck cancer patients undergo radiation therapy after surgery. Radiotherapy results in problem in bone healing hence osseointegration gets delayed. (Osseointegration- defined as a direct structural and functional connection between living bone and placed implant). Usually, dental implant placement and the process of rehabilitation takes place after one year of radiotherapy to reduce the effect of radiation on healing. While sufficient literatures are available highlighting the need to delay dental implant placement by at least a year in radiated patients but there is no clinical proof that justifies any need to delay in the placement of artificial teeth on osseointegrated implants (termed as loading of implants). Conventionally, placement of artificial teeth in non-irradiated bones takes place at 3 months after implant placement. Empirically, artificial teeth is carried out at 6 months after dental implant surgery in irradiated jaw bones is mainly based on assumption that radiated bone regenerates at slower rate than non radiated jaw bones.

The objective of this research is to investigate if earlier osseointegration (less than 6 months) of dental implants is achievable in radiated bone. This would directly impact the speed of the rehabilitation process and thus, the quality of life of the patients.

During the study, at three months it will be started checking whether the implants that are placed are integrating to the bone in an expected way or there is any deviation from the normal. For that it is needed to measure the stability of the implant by using an instrument. This instrument measures Implant Stability Quotient (ISQ) i.e level of stability and integration of dental implants with the jaw bone. This ISQ measurement will be done immediately after placement of implants and at 3,6 months. This protocol will be followed for half of the placed implants in the jaw (those will be categorized as study implants), while the rest of the implants will be left undisturbed as it is done conventionally (those will be categorized as control implants) and ISQ will be measured after 6 months.

At the end of 6 months, a prosthesis will be placed in case all the implants have attained an ISQ comparable to the control implants or more than desired value (65±10).

The study will be conducted at Tata Memorial Hospital with the implant surgery aimed to be completed by 18 months.

0 to 12 Months: Patient screening, consenting, recruitment and dental implant placement. 06-18 Months: Prosthetic rehabilitation (placement of artificial teeth)

At present, there are lack of studies that justifies any need to delay the placement of prosthesis on osseointegrated implants (termed as loading of implants).This would directly impact the speed of rehabilitation process and thus, the quality of life of the patients. Hence we can give teeth / denture early to patient. It will also help the clinician to assess the impact of different factors (dose of radiation and type of bone) on the osseointegration of the dental implant.