INTRODUCTION
Life is not merely being alive, but being well. In aged, dental health forms an integral part of overall health and oral rehabilitation entails the performance of all the procedures necessary to produce healthy, esthetic, well functioning and self-maintaining masticatory mechanism.
The connector is that part of a fixed partial denture or splint that joins the individual components (retainers or pontics) together. Rigid connector is cast, soldered or fused union between retainer and pontic where as non-rigid connector permits limited movements between otherwise independent members of the fixed partial denture prosthesis. [1] Non-rigid connectors are usually indicated to relieve stress or to accommodate mal-aligned fixed partial denture abutments. They are usually dove tail / tenon-mortise, loop connectors, split pontic or cross pin -wing connectors. Among these, loop connectors or spring cantilever designs are used when an existing diastema is to be maintained in a planned fixed prosthesis. [2] It consists of a loop on the lingual aspect of the prosthesis that connects adjacent retainer or pontics. Meticulous care in designing should be followed in order to facilitate adequate plaque control.
Precision attachments are wholly or partially machined accessories used for retention of removable prosthesis. Towards the end of the 19th century Parr, Peeso, Chayes, and other experts designed gadgets which were subsequently called as precision attachments. These devices allowed prostheses to combine the advantages of fixed and of removable restorations. [3] They retain and attach a removable bridge or partial denture on natural teeth or implants. Some serve as retainers for full dentures (overdentures) where few abutments remain. The main purpose of each precision attachment besides retention is its concealment within or under a restoration as an aesthetically better alternative to a visible clasp retainer. Precision attachments have been constructed into two halves, a matrix and a patrix, the halves being so arranged that they articulate with one another to form a precise but separable joint. [4] There are numerous attachments available. Among them Rhein 83 system are simple and offer spherical retention. The versatility of applications to many restoration solutions offered by the spherical retention is widely recognized in the treatment of the partially edentate and totally edentate patients. [5]
Here we describe a case report of oral rehabilitation using connectors and attachments.
CASE REPORT
A patient aged 55 years, came with a desire to replace his missing tooth [Figures 1 and 2]. Intraoral examination revealed partial edentulous spaces with few healing sockets which had a history of recent extraction. Patient also had history of pain and swelling in relation to mandibular right posteriors few months back which subsided on taking medications. Radiograph showed deep dental caries in relation to mandibular first molar along with deep cervical caries in relation to the premolars. Lower left second premolar also had deep dental caries involving the pulp. There were generalized diastema in maxillary anteriors and the patient wished to maintain the same. Diagnostic impression was made following through oral prophylaxis. Treatment was executed after complete healing of extraction sockets.
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Figure 1: Preoperative photograph
Figure 2: Preoperative photographs
All the teeth with deep dental caries involving the pulp were treated endodontically. The lower right third molar was severely tilted and needed a crown to support a bridge. Hence, single visit intentional root canal treatment was done. Existing occlusion was used as a guide and facilitated oral rehabilitation.
For maxillary arch, on the right side a long span 5 unit bridge replaced missing first and second molar. On the left side, to replace missing premolar and central incisor, a long span bridge taking support of canine, second premolar and first molar was fabricated. The central incisor was replaced by using a loop connector in order to maintain the diastemata. An additional loop also crossed the arch and rested on the cingulum of the adjacent central in order to get adequate support. [Figure 3] A small cantilever, of a size of premolar, extended from the first molar for extra occlusal contact against the opposite dentition. Small abrasion on the labial surface was corrected with micro filled composites.
Figure 3: Maxillary bridges with loop connector
For mandibular arch, right side was rehabilitated with fixed prostheses. Left side had distal extension and was rehabilitated with unilateral Rhein 83 spherical precision attachments. Elastic retentive caps on the intaglio surface, along with the denture flanges of the removable partial denture provided adequate retention and stability [Figures 4–7].
Figure 4: Rhein 83 extra coronal spherical attachment
Figure 5: Rhein 83 extra coronal spherical attachment
Figure 6: Rhein 83 extra coronal spherical attachment
Figure 7: Rhein 83 extra coronal spherical attachment
Patient was educated for proper oral hygiene and was scheduled for regular periodic recall visits. Thus healthy, esthetic, well functioning and self-maintaining masticatory mechanism was restored [Figures 8–10].
Figure 8: Final photograph
Figure 9: Final photograph
Figure 10: Orthopantomograph
DISCUSSION
Partial edentulism of an anterior region poses severe aesthetic problems and presence of diastema or an increased mesiodistal pontic space adds a woe to it. The dilemma in treating these cases involves whether to use all the pontic space or to maintain the space between the teeth. The former treatment option uses a conventional bridge with increased mesiodistal width of the retainers and the pontics which may not be acceptable for aesthetic reasons. If a single maxillary incisor is missing, cantilevered fixed bridge with loop connector to the adjacent strong abutment is a viable option to maintain maxillary anterior diastema. [6] In anterior region, lateral incisor is considered as the weakest abutment and canine as the strongest abutment tooth. [1] In this case adjacent tooth was lateral incisor hence it was excluded from the design and a modified spring cantilever bridge with canine as an abutment was used with a loop connector to maintain the diastema between the teeth. The disadvantage of a long spring cantilever bridge is that abutment tooth tends to move. A laboratory study reported that abutment teeth moved mesio-buccally and the elbow of the connecting bar moved off the palate indicating the presence of fulcrum along the anterior section of the bar. [7] To prevent this generally double abutments are used on same side but if one of the abutment is weak, as in this case the lateral incisor, it may result in uneven distribution of stress and fracture of the cement lute of the weakest retainer, resulting in leakage and caries and ultimately failure of the prosthesis. [6] To overcome the lever problem it was decided to modify the design and thus an adhesive retentive extension was used to take support and retention from the contra lateral maxillary central incisor. The pontic was provided with only centric occlusal contact. Any lateral or protrusive contacts were eliminated to minimize lateral forces on it.
Despite the fact that FPD is better tolerated by the patients in comparison to RPD, the later is still prevalent in partially dentate people. [8] Contemporary treatment in patients with distal extension ridges involves use of implants but in this patient removable dental prosthesis (RDP) in left side of mandibular arch was an apt option because of anatomic, as well as economic factors. Generally retention of RDP is obtained from clasp, telescopes, or some form of attachments. An intact caries-free tooth intended as a retentive abutment is best provided with a clasp or adhesive attachments. [9] A drawback of clasp retained RDP is that it is often associated with extensive treatment planning and design related complications. Rates of unsuccessful treatment for clasp retained cast RPDs range from 3% to 40% with mean being 26%. [10] Another major disadvantage of clasp retained RDP is that the visible component jeopardizes the esthetics. [11] Though survival rate of vital tooth as telescopic abutment in retaining RDP is 89%, root canal treatment increases the risk factor of abutment loss. [12] Hence, RDP fabricated with precision/semi precision attachments for retention and support are the best prosthesis available to dentistry where fixed restorations are contraindicated. [13] Precision attachment offers considerable advantages in dentistry because of their flexibility. The attachments used could be of intracoronal or extracoronal to the existing abutment teeth. [9] Extracoronal attachment is preferred over intra coronal attachments as the latter obviate the risk for over contouring of distal portion of the crown, which can result in periodontal breakdown as a result of increased plaque retention. [4] In this case, lower left premolar was endodontically treated hence considering the various aforementioned facts, the clasp, telescopic abutment or adhesive attachment was ruled out and extracoronal attachment was used. Another supportive article has charted out that in a treatment plan of anterior FDP and distal extension RDP, extracoronal attachment is preferred over a telescope attachment because of aesthetics and psychological reason. [9] It is a well known fact that the movement of RDP transmits force to the distal most abutment. [14] To minimize the stress on distal abutment, both the lower premolars were splinted by providing crowns on them as a study has suggested that most distal abutment splinted to the tooth anterior to the abutment significantly reduces the stress transmission to the supporting structures in these type of cases. [15] By following the philosophies of impression making of distal extension, stress transmission was further reduced. [16]
CONCLUSION
Treatment planning is crucial to success when considering any form of tooth replacement. Whichever treatment modality is finally selected, it should suit the needs of the patient, be carefully planned and skilfully executed. If the situation demands, the possibility of unconventional designs such as modified spring cantilever or precision attachments should be well explored and adopted to give the patient back his/her lost confidence and charming smile.
Source of Support:
Nil.
Conflict of Interest:
No.
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