A progressive anterior maxillary bone loss can be seen in cases of complete maxillary denture opposed by the distal extension RPD. A variety of similar situations when a maxillary partial denture with missing front teeth is functioning against an anterior fixed dentition or an implant-supported prosthesis (root-form, subperiosteal, ramus frame, transmandibular implant designs) can also eventually lead to the CS condition.²⁹ 

Based on pathogenesis of this syndrome, four possible treatment modalities can be conceptually applied to attenuate or correct a traumatic anterior hyperfunction and treat CS. They are:

1. a properly designed removable mandibular partial denture around stable, mildly super-erupted anterior teeth opposed by a complete maxillary denture with even distribution of occlusal stresses over hard/soft tissues and careful maintenance through the follow-up care with a goal to preserve posterior occlusion.^3,35 In some cases, mandibular anterior teeth may need to be treated with root canal and have their clinical crowns shortened to place opposing maxillary incisors in a proper position;
2. an extraction of anterior mandibular teeth with/without alveoloplasty and construction of functional complete upper and lower dentures with a stable posterior occlusion with punctilious follow-up care and maintenance protocol;
3. an implant treatment of existing dentition with or without extraction of teeth to re-establish solid posterior occlusion with an implant-assisted or supported maxillary or mandibular prostheses;
4. using advanced maxillary bone grafting techniques to rebuild the maxillary anterior alveolar ridge in concert with one of the previous three options. The first two treatment modalities are conventional pre-implant symptomatic restorative techniques. The last two seem to be a causative physiologic surgical-prosthetic rehabilitation of the stomatognathic system that can prevent continuous bone deterioration and related signs and symptoms in CS patients.

According to our classification, Class I combination syndrome patients with totally edentulous maxilla can be treated in many cases with an implant-retained or supported maxillary prostheses based on 2 to 4 splinted implants placed in posterior maxillary regions opposed by the mandibular bilateral distal extension RPD. This can help to redistribute the occlusal load to the posterior regions and correct the condition.

Class II and III patients with partially edentulous maxilla and salvageable posterior teeth may best be treated with a well-designed and maintained conventional RPD. An implant prosthesis can be an alternative treatment in these cases (Table). Patients with poor posterior maxillary teeth may need an extraction and immediate or delayed implant placement with or without sinus lift for implant-retained or implant-supported prostheses. Due to poor quality of the posterior maxillary bone (type 3 or 4), at least 2 implants of sufficient length should be attempted on each side. After osseointegration, they should be splinted to increase the resistance to occlusal forces. An implant-supported prosthesis may demonstrate a bone-preserving effect that is the opposite of a conventional denture treatment that promotes continuing ridge resorption.³⁶

A preservation of the health of natural dentition and its masticatory function are important keys to prevent progression of the CS. It is essential for dental practitioners (restorative and surgical) to identify initial symptoms of CS and initiate early corrective measures. An immediate or early replacement of lost teeth with dental implants can be one of the most effective treatment options that can circumvent the development of this syndrome. A multi-disciplinary approach is paramount to accomplish a complex task of comprehensive dental treatment of CS patients.

A proposed classification of combination syndrome may help to identify causes and forces of bone remodeling and assist in predicting stages of development of this condition, guiding a clinician towards an appropriate treatment protocol. Implant stomatognathic rehabilitation seems to be the most promising approach for these patients.

Table of classification of Combination Syndrome (CS)

Extension Table of classification of Combination Syndrome (CS)